Physiology Entire Class info

Troponin C (TnC)

binds calcium

Sarcolemma

plasma membrane of a muscle fiber

phase 0

primarily driven by Na+ influx through the fast Na+ channels.

Kartagener Syndrome

primary ciliary dyskinesia, a dynein arm defect, male and female fertility, bronchiectasis, recurrent sinusitis, chronic ear infections, conductive hearing loss, and situs inversus

Sinus tachycardia

regular rhythm, above 100 beats/minute

Calsequestrin

calcium-binding protein within the sarcoplasmic reticulum which aids in storage of intracellular Ca2+

Osmolarity

concentration of osmotically active particles in a solution?

terminal cisternae

enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules.

Phase 1

follows the closure of the fast Na+ channels, and the downward deflection is driven by a net outward current driven by potassium efflux from the cell.

metabolic alkalosis

high pH, high HCO3

Thin Ascending limb

impermeable to water Passive transport: solute moves out of the thin ascending limb without water the tubular fluid becomes progressively hyposmotic Creates Corticopapillary Osmotic Gradient

Adrenal Sufficiency

increased ICF volume, decreased ECF volume, decreased osmolarity

mannitol

increased water excretion owing to the presence of a poorly reabsorbed substance in the lumen of the proximal tubule

Nephritic syndrome

inflammation of the glomerulus, Hypertension, Oliguria, Hematuria, Proteinuria

Pseudohypoparathyroidism

inherited defect in the tubular receptors - urinary phosphate and cAMP are decreased, hypocalcemia, hyperphosphatemia

Opiates, barbiturates, anesthetics, Lesions of the central nervous system, Central sleep apnea, Oxygen therapy

inhibition of the medullary respiratory center

61. A 70-year-old female comes to her doctor complaining of increased sensitivity to cold, constipation, fatigue, and dry hair. As part of her work up , her Doctor notices that her thyroid hormone levels are low. Although thyroid hormone is a lipid-soluble hormone, it differs from most lipid-soluble hormones Because it:

stored in large quantities

Allosteric regulation

involves the binding of the drug to a protein at a site other than the active site, which either increases or decreases the activity of that protein.

Proteolytic modification

is a form of posttranslational modification that involves the hydrolysis of peptide bonds of a protein by a protease (eg, cleavage of a zymogen) to form an active enzyme.

upregulation

is the increase in population of receptors on a cell surface •This is usually due to chronic blockage of the receptor or lack of stimulus •This will occur in denervation, chronic administration of antagonists

Renal artery

At which site is systolic blood pressure the highest? Select one: a. Renal artery b. Right atrium c. Renal vein d. Pulmonary artery e. Central vein f. Aorta

Thin descending limb

Passive transport: water moves out - passively reabsorbs H2O Impermeable to Na+ the tubular fluid becomes progressively hyperosmotic Urea secretion

GFR x plasma glucose

The filtered load of glucose

Ach- Na+ channels

What type of channels are at the motor end plate?

Antidiuretic hormone In general, peptide hormones are water soluble and are not highly bound by plasma proteins. Antidi- uretic hormone, a neurohypophysial peptide hormone, is virtually unbound by plasma proteins. In contrast, steroid and thyroid hormones are highly bound to plasma proteins.

Which of the following hormones is largely unbound to plasma proteins? Select one: a. Progesterone b. THyroxine (T4) c. Estradiol d. Cortisol e. Antidiuretic hormone

3 -Aminobutyric acid (GABA) 3-Aminobutyric acid (GABA) is an inhibitory neurotransmitter. Norepinephrine, glutamate, serotonin, and histamine are excitatory neurotransmitters.

Which of the following is an inhibitory neurotransmitter in the central nervous system (CNS)? Select one: a. Serotonin b. 3 -Aminobutyric acid (GABA) c. Histamine d. Norepinephrine e. Glutamate

Primary Hyperaldosteronism

- Increased secretion of aldosterone from adrenal gland - hypokalemia

83. The lung and chest wall compliance curve for a healthy individual are shown on the slide below Airway pressure Which of the following is the best estimate of the intrapleural pressure at the point on the graph marked by the dot in the center, if pressure inside the Whole respiratory system corresponding to this dot = 0?

-5 cm H2O

respiratory acidosis

low pH, high CO2

metabolic acidosis

low pH, low HCO3

decreases

A negative inotropic effect is one that __________ myocardial contractility.

Aspiration, Obstructive sleep apnea, Laryngospasm

Airway obstruction

Low arterial PCO% suppressing the activity of the medullary chemoreceptors THis patient would have increased alveolar ventila- tion, therefore resulting in a decrease in arterial PCO2. THe effect of this decrease in PCO2 would be an inhibi- tion of the chemosensitive area and a decrease in ventilation until PCO2 was back to normal. Breathing high O2 does not decrease nerve activity sufficient to decrease respiration. Response of peripheral chemore- ceptors to CO2 and pH are mild, and do not play a major role in the control of respiration.

An anesthetized male is breathing with no assistance. He is then artificially ventilated for 10 min at his normal tidal volume but at twice his normal frequency. He is ventilated with a gas mixture of 60% O2 and 40% N2.THe artificial ventilation is stopped and he fails to breathe for several minutes. THis apneic episode is due to which of the following? Select one: a. Low arterial PCO% suppressing the activity of the peripheral chemoreceptors b. Low arterial PCO% suppressing the activity of the medullary chemoreceptors c. High arterial PO% suppressing the activity of the peripheral chemoreceptors d. Decrease in arterial pH suppressing the activity of the peripheral chemoreceptors e. High arterial PCO% suppressing the activity of the medullary chemoreceptors

S2 heart sound

Closure of the semilunar valves (pulmonary and aortic)

spironolactone

Competitive aldosterone receptor antagonists ↓ Na+ reabsorption ↓ K+ secretion

muscle fiber

muscle cell

Ingestion of NaHCO3 Milk-alkali syndrome

Gain of HCO3 results in

118. Which of the following labeled curves best describes the variation in blood estradiol concentration during the menstrual cycle?

Graph D

95. Triiodothyronine [T3] is more potent than thyroxine [T4] for the treatment of hypothyroidism because of which of the following?

Greater receptor affinity

diabetes insipidus

Head injuries often interfere with proper release of ADH and patients may develop

Leakage channels

K+ - resting transmembrane voltage of the excitable membrane is what type of channel?

32. A 35-year-old man with controlled diabetes mellitus is enrolled in clinical study examining the difference between serum glucose levels and urine glucose levels in patients with type 2 diabetes mellitus. As part of this study, the patient eats a large carbohydrate-rich meal and then has serum and urine glucose levels measured. Although his serum glucose level begins to rise rapidly, glucose only becomes detectable in his urine several hours later. Glucose does not become immediately detectable in his urine because of what feature of the nephron?

Kinetics of sodium-dependent symporter in the proximal convoluted tubule

Vomiting Hyperaldosteronism

Loss of H+ results in

Rectal distension The rectum is empty of feces most of the time. When a mass movement forces feces into the rectum, the desire to defecate is initiated immediately. Reflex contraction of the rectum and relaxation of the internal anal sphincter follows. If a person is in a place where defecation is possible (like a bathroom), the external anal sphincter is consciously relaxed and the feces is expelled. It should be clear that mass movements do not cause duodenal peristalsis, gastric retropulsion, or hunger sensations.

Mass movements constitute an important intestinal event that lead to bowel movements. Mass movements cause which of the following? Select one: a. Hunger sensations b. Duodenal peristalsis c. Rectal distension d. Contraction of internal anal sphincter e. Gastric retropulsion

PAH

Measurement of renal plasma flow

23. A 40-year-old man has the cardiac phonogram shown. A normal tracing is also shown. Which of the following is the most likely diagnosis?

Mitral regurgitation

91. The diagram shows the force-velocity relationships for isotonic contractions of free muscle fibers. The variation in the three curves most likely results from differences in which of the following?

Myosin ATPase activity

Voltage-gated channels

Na+ channel - activation gate opened by depolarization; inactivation gate closed by depolarization is what type of channel?

19. A 38-year-old woman, gravida 2, para 2, is brought to the emergency department by her husband after an episode of unconsciousness. She delivered a healthy infant two weeks ago and the postpartum course was complicated by severe vaginal bleeding, for which she required 4 units of packed red blood cells. Since the blood transfusion, she has had decreased milk production and has felt fatigued. Her pulse is 118/min and blood pressure is 104/63 mm Hg. Her finger-stick glucose concentration is 34 mg/dL (low). Serum thyroid- stimulating hormone and thyroxine levels are low. Which of the following is the most likely cause of this patient's condition?

Pituitary ischemia

60. A 10-year-old boy is brought to the physician because of persistent bleeding after a tooth extraction. His mother reported that in the past, whenever he had A bloody nose, it would last longer than expected. She says that her daughter also has similar problems. She has never seen any blood in his urine or Stool; no episodes of swelling and bleeding into the knee joint. The boy is diagnosed von willebrand disease. Which of the following is most likely to be abnormal in this patient?

Platelet adhesion

cations

Positive charged ions?

Hyponatremia

no change in RMP and smaller action membrane potential

Gitelman syndrome

Reabsorption defect of NaCl in DCT - similarly to lifelong thiazide diuretic use

0.3% NaCl

Red blood cells from a healthy individual were placed in each of the following solutions and observations were made after 1 hour. Cells would have most likely have lysed when placed in: Select one: a. 0.9% NaCl b. 0.3% NaCl c. 2.5% NaCl d. 1.2% NaCl

sigmoidal shape due to positive cooperativity

Shifting the curve to the right - ↓ Hb affinity for O2 (facilitates unloading of O2 to tissue) Shifting the curve to the left - ↑ affinity - ↓ O2 unloading - renal hypoxia -> ↑ EPO synthesis

A THe forced vital capacity (FVC) is the vital capacity measured with a forced expiration. e forced expira- tory volume in one second (FEV1) is the amount of air that can be expelled from the lungs during the first second of a forced expiration. e FEV1/FVC for the normal individual (curve X) is 4 L/5 L 80% and 2 L/4 L 50% for the patient (curve Z). e FEV1/FVC ratio has diagnostic value for differentiating between nor- mal, obstructive, and constricted patterns of a forced expiration.

THe diagram above shows a forced expiration for a healthy person (curve X) and a person with a pulmonary disease (curve Z). What is the FEV1/FVC ratio (as a percent) in these individuals? Select one: a. A b. B c. C d. D e. E f. F

optimal length - 2.0μm and 2.2μm

The length at which the fiber generates the most active tension is called the?

conduction system disturbances, inferior wall MI, and digitalis toxicity

Third-degree heart block is caused by?

Blocks H+-K+-ATPase

Where does the drug omeprazole act?

Sinus arrhythmia

a change of the heart rate produced by the normal variation in the rate of phase 4 depolarization of the SA nodal pacemaker cells between inspiration and expiration?

Syncope (fainting)

a transient loss of consciousness caused by an inadequate blood flow to the brain.

thin filaments

actin

ADH

allows for reabsorption of water in the collecting ducts of the kidney

Hyperkalemia

an increase in extracellular potassium depolarizes the cell (RMP is less negative) and decreases the size of action potential

Permeability

the ease with which a solute diffuses through a membrane?

17a-Hydroxylase

the only congenital adrenal hyperplasia that manifests with decreased sex hormones, as 17a-hydroxylase is the enzyme needed for the pathway of sex steroid hormone synthesis.

Absolute refractory period

the period during which another action potential cannot be elicited, no matter how large the stimulus.

Diffusion potential •membrane is permeable to the ion •size depends on the size of the concentration gradient •sign depends on whether the diffusing ion is + or - charged

the potential difference generated across a membrane because of a concentration difference of an ion.

phase 3

the repolarization phase that is driven by potassium efflux, and corresponds to the T wave on a typical EKG tracing.

34. A 32-year-old woman comes to her physician, complaining of persistent abdominal pain that occurs after eating, particularly when she eats bread and other grain-based foods. The doctor orders a biopsy, which shows significant inflammation of the small intestine. Intestinal levels of which of the following proteins would be expected to increase?

trypsinogen

PAH clearance

used to measure renal plasma flow because it is filtered, not reabsorbed and almost completely secreted.

150 ml Physiologic dead space must be = anatomic dead space

what is anatomic dead space?

mitral regurgitation

•High left atrial pressure •Murmur: systolic, begins at S1 and continues to S2 pansystolic •↓ ESV, ↑ EDV , ↑ ventricular filling, ↑ SV, •No true isovolumetric phase •decompensated heart failure

58. A 52-year-old man has intermittent episodes of supraventricular tachycardia. During these episodes, he has a pulse of 190 to 200/min and systolic Blood pressure of 60 to 80 mm Hg. which of the following is the most likely cause of the hypotension?

Inadequate ventricular filling

prevent degradation of ACh

How does neostigmine affect the neuromuscular junction?

Action Potential Amplitude will be decreased

How is the action potential affected when there is rapid inactivation of the voltage-gated sodium channels

S4 heart sound

oscillations of the ventricles during atrial contraction •Recorded during atrial systole - ventricular diastole

Aquaporins -Opened constantly -introduction to membrane controlled by ADH

channel proteins that facilitate the passage of water?

HERG channels

Human-Ether-A-Go-Go Related Gene codes for a subunit of the delayed rectifying potassium channels in the heart. •Interference with these channels will prolong the cardiac action potential and potentially induce a life-threatening arrhythmia •Many drugs may block or otherwise interfere with these K channels

17a-Hydroxylase deficiency

characterized by deficits in glucocorticoid and sex steroid synthesisand increased mineralocorticoid synthesis.

Folate deficiency

Macrocytic anemia: MCV > 100 fL, ↓ RBC count & Htc , Macrocitosis (Megaloblastic RBC)

inulin clearance, creatinine

Measurement of Glomerular Filtration Rate

Low

(high/low) _____________ CARDIAC OUTPUT -> SNS activation + RAAS activation = ↑TPR + H2O and Na+ retention , increased ANP

Dantrolene

-Mechanism: prevents release of Ca2+ from the sarcoplasmic reticulum of skeletal muscle. -Use: malignant hyperthermia and neuroleptic malignant syndrome (a toxicity of antipsychotic drugs).

S3 heart sound

rapid ventricular filling phase •during transition between rapid filling and slow filling of ventricle - ventricular diastole

Secondary active transport

A 52-year-old man comes to the clinic to discuss his poorly controlled type 2 diabetes mellitus. His past medical history also includes hypercholesterolemia and peripheral vascular disease. His medications include metformin and lovastatin. His temperature is 37°C (98.6°F), pulse is 72/min, respirations are 14/min, and blood pressure is 136/78 mm Hg. Examination shows no abnormalities. He is started on a medication that blocks the reabsorption of glucose in the proximal convoluted tubule. This medication inhibits which of the following methods of transport across the cell membrane? Select one: a. Facilitated diffusion b. Primary active transport c. Simple diffusion d. Bulk transport e. Secondary active transport

-50° The mean electrical axis can be determined plot- ting the resultant voltage of the QRS for leads I, II, and III. e result is as is shown above and has a value of 50°.

A 60-year-old woman had the following EKG recorded at a local emergency room following an automobile accident. Her weight was 70 kg and her aortic blood pressure was 140/80 mm Hg. What is the mean electrical axis calculated from standard leads I, II, and III shown in her EKG? Select one: a. +100 b. -50° c. -12° d. +170 e. -90°

proximal convoluted tubule (PCT)

first section of the renal tubule that the blood flows through; reabsorption of water, ions, and all organic nutrients

350 mmol mannitol

A 62-year-old male presents to the emergency room with an acute onset of aphasia and hemiparesis. A computed tomography (CT) scan reveals an increase in intracranial fluid. Which of the following solutions will be most effective in reducing intracranial pressure following a large hemispheric stroke? Select one: a. 350 mmol mannitol b. 250 mmol glycerol c. 350 mmol urea d. 150 mmol sodium chloride e. 250 mmol glucose

aortic regurgitation

A 66-year-old male is referred to a cardiologist for evaluation. Physical examination reveals a diastolic murmur prominent over the left sternal border, a decrease in diastolic pressure, and an increase in pulse pressure. Which of the following is the most likely diagnosis? Select one: a. Pulmonic stenosis b. Aortic stenosis c. Pulmonary regurgitation d. Mitral valve prolapse e. Aortic regurgitation

50. A 57-year-old woman with a history of severe chronic asthma presents for a right heart catheterization to evaluate for pulmonary hypertension. A catheter Is inserted through her femoral vein and into her pulmonary artery to measure pulmonary vascular resistance. At what point in the respiratory cycle will Her pulmonary vascular resistance be lowest?

After expiration of a normal tidal volume

Compliance is change in volume/change in pressure. this calculates to 1000 ml/8 cm H2O equaling 125. 125 ml/cm H2O

A man inspires 1000 ml from a spirometer. the intrapleural pressure was = 4 cm H2O before inspiration and = 12 cm H2O the end of inspiration. What is the compliance of the lungs? Select one: a. 100 ml/cm H2 O b. 50 ml/cm H2O c. 150 ml/cm H2 O d. 250 ml/cm H2O e. 125 ml/cm H2O

lying between 30 and 90 degrees

A normal QRS axis is typically defined as?

Phase 0: L-type calcium channels open, causing depolarization. Phases 1 and 2 are absent. Phase 3: Potassium channels open, causing repolarization. These channels can be affected by a number of pharmacologic mechanisms. Phase 4: Funny channels with a slow leak of potassium out of the cell cause a transient depolarization toward threshold.

A number of channels are involved in the cardiac action potential in the AV node. Describe what happens in each phase

7.5 L/min Alveolar ventilation = Frequency x (VT - VD) = 15/min x (650 - 150) = 7.5 L/min

A patient has a dead space of 150 ml, functional residual capacity of 3 L, tidal volume of 650 ml, expiratory reserve volume of 1.5 L, a total lung capacity of 8 L, respiratory rate of 15 breaths/min. What is the alveolar ventilation? Select one: a. 6.0 L/min b. 9.0 L/min c. 5 L/min d. 7.5 L/min

motor unit

All the muscle fibers innervated by a single nerve fiber?

1:20

The graph below illustrates the pressure-volume curves for the arterial and venous systems. Which of the following is the approximate ratio of the arterial compliance to the venous compliance? Select one: a. 1:10 b. 15:1 c. 1:1 d. 10:1 e. 1:20

the muscle's ATPase activity (myosin molecule)

The velocity of shortening reflects the speed of cross-bridge cycling, determined by?

D When a person is anemic, there is a decrease in con- tent. e oxygen saturation of hemoglobin in the arterial blood and the arterial oxygen partial pressure are not affected by the hemoglobin concentration of the blood.

Which of the points on the following figures represent arterial blood in a severely anemic person? Select one: a. A b. B c. C d. D

S1 heart sound

closure of AV valves (mitral and tricuspid)

vitamin K deficiency

decreased synthesis of factors II, VII, IX, X, protein C, protein S. Warfarin inhibits vitamin K epoxide reductase. Neonates lack enteric bacteria, which produce vitamin K. Early administration of vitamin K overcomes neonatal deficiency/coagulopathy.

First- degree heart block

defined as a higher-than-normal PR interval (greater than 0.2 seconds) generally asymptomatic and is characterized by a PR interval > 200 msec

glucosuria

excretion or spilling of glucose in the urine: •In uncontrolled diabetes mellitus •pregnancy •congenital abnormalities of the SGLT

thick filaments

myosin, which binds and hydrolyzes ATP

symport eg: SGLT - glucose, galactose transport

solutes move in the same direction?

electrochemical equilibrium

the chemical and electrical driving forces that act on an ion are equal and opposite, and no more net diffusion of the ion occurs at which point?

extrinsic pathway the extrinsic pathway begins with the release of tissue thromboplastin in response to vascular injury or contact between traumatized extravascular tissue and blood. Tissue thromboplastin is composed of phos- pholipids from the membranes of tissue.

the coagulation pathway that begins with tissue thromboplastin is Select one: a. extrinsic pathway b. fibrin stabilization c. common pathway d. intrinsic pathway

increased preload

venous return is increased end-diastolic volume is increased

increased contractility

ventricle can develop greater tension and pressure during systole

40. The diagram shows an action potential for a skeletal muscle fiber recorded by an intracellular microelectrode inserted near the motor end plate. The threshold potential for this particular myocyte is most likely within which of the following voltage ranges?

-60 to -70

uncoordinated contraction of myofibrils

Decrease in T tubules will lead to?

47. Figure shows a gastric parietal cell with selected membrane transporters and channels. What do X, Y, and Z represent in figure?

A

IGF-1 The actions of insulin are mediated at the cellular level by binding of insulin to its receptor, followed by autophosphorylation of tyrosine residues on the insulin receptor. This generates a tyrosine kinase that participates in an intracellular signaling cascade. This is the same signaling pathway of IGF-1 (insulin growth factor-1), PDGF (platelet derived growth factor), and FGF (fibroblast growth factor). Inhibition of tyrosine kinase function would prevent downstream signaling and block the physiologic changes associated with the hormone, regardless of the amount of hormone present in the blood.

A researcher team is studying diabetes mellitus. The team is trying to understand the molecular pathways involved in insulin resistance. They create a strain of genetically altered mice with a mutated insulin receptor that is only partially activated upon ligand binding. Under normal cellular conditions, the insulin-receptor mediated signaling cascade is analogous to which of the following? Select one: a. BNP b. Erythropoietin c. ACTH d. Cortisol e. IGF-1

104. As part of the digestive process in the human, pancreatic proteases within the small intestine are normally actuated. Which of the following substances From the duodenal epithelium triggers this activation?

Enteropeptidase

Intrinsic pathway the prothrombin time, test of extrinsic pathway, is the time required for clot formation following addition of tissue thromboplastin. is is normal so no problem with extrinsic. Partial thromboplastin time is a test of the intrinsic pathway. is is longer than normal so there is a problem with the intrinsic pathway. Bleeding time tests platelets, and since this is normal there is no problem with the platelets.

A teenaged boy with numerous nosebleeds was referred to a physician for evaluation prior to a minor surgery. His prothrombin time (PT) was 11 sec (11-15 sec normal), partial thromboplastin time (PTT) was 58 sec (25-40 sec normal), and bleeding time was 6.5 min (2-7 min normal). Which of the following is most likely abnormal in this young man? Select one: a. Extrinsic pathway b. Intrinsic pathway c. Production of clotting factors by the liver d. Decreased platelet number e. Defective platelets

Prolactin inhibits secretion of gonadotropin-releasing hormone from the hypothalamus

A woman with a 2-year-old son comes to her physician because she has been unable to conceive a second child for more than a year. The woman is currently breastfeeding her son. Which of the following best explains the physiologic mechanism currently preventing her from getting pregnant? Select one: a. Prolactin inhibits secretion of gonadotropin-releasing hormone from the hypothalamus b. Prolactin inhibits secretion of estrogen from the ovaries c. Prolactin inhibits secretion of progesterone from the corpus luteum d. Prolactin inhibits secretion of follicle-stimulating hormone from the anterior pituitary gland e. Prolactin inhibits secretion of luteinizing hormone from the anterior pituitary gland

syndrome of inappropriate ADH (SIADH)

ADH are abnormally high, increase water reabsorption by the late distal tubule and collecting ducts, urine hyperosmotic, diluting the plasma osmolarity

Anion gap equation

AG = Na - (Cl + HCO3)

glucose clearance

AT NORMAL PLASMA CONCENTRATIONS GLUCOSE IS COMPLETELY REABSORBED IN PROXIMAL TUBULE BY Na/glucose COTRANSPORT DIABETES (~>160) --> GLUCOSURIA all transporters fully saturated at 350

121. A healthy 40-year-old woman inhales to total lung capacity and then exhales forcefully. The rate of expiratory airflow is highest at total lung capacity and Decreases linearly as exhalation continues. Which of the following is the most likely cause of the observed decrease in expiratory airflow?

Airway compression

D Duodenal ulcer patients have about 2 billion parietal cells and can secrete about 40 mEq H! per hour. Normal individuals have about 50% of these values. Plasma gastrin levels are related inversely to acid secretory capacity because of a feedback mechanism whereby antral acidification inhibits gastrin release. THus, plasma gastrin levels are reduced in duodenal ulcer patients. Maximal acid secretion and plasma gastrin levels are not diagnostic for duodenal ulcer disease because of significant overlap with the normal population among individuals in each group

An 84-year-old man with hematemesis and melena is diagnosed with a duodenal ulcer. A patient diagnosed with a duodenal ulcer is likely to exhibit which of the following? Select one: a. A b. B c. E d. D e. C

Relative refractory period

An action potential can be elicited during this period only if a larger than usual inward current is provided

increased cardiac output for a given end-diastolic volume An increase in contractility produces an increase in cardiac output for a given end-diastolic volume, or pressure. The Frank-Starling relationship demonstrates the matching of cardiac output (what leaves the heart) with venous return (what returns to the heart). An increase in contractility (positive inotropic effect) will shift the curve upward.

An increase in contractility is demonstrated on a Frank-Starling diagram by Select one: a. increased cardiac output for a given end-diastolic volume b. decreased cardiac output for a given end-diastolic volume c. increased cardiac output for a given end-systolic volume d. decreased cardiac output for a given end-systolic volume

Capillary wall hydraulic conductivity An increase in capillary wall permeability to water would increase capillary filtration rate, whereas increases in arteriolar resistance, plasma colloid osmotic pressure, and interstitial hydrostatic pressure would all decrease filtration rate. Plasma sodium concentration would have no effect on filtration.

An increase in which of the following tends to increase capillary filtration rate? Select one: a. Interstitial hydrostatic pressure b. Plasma sodium concentration c. Arteriolar resistance d. Plasma colloid osmotic pressure e. Capillary wall hydraulic conductivity

Lambert-Eaton myasthenic syndrome

Antibodies against presynaptic, voltage-gated Ca2+ channels - muscle weakness improves with muscle use

1 millimolar CaCl2 Osmolarity is the concentration of particles (osmolarity = g Å~ C). When two solutions are compared, that with the higher osmolarity is hyperosmotic. The 1mM CaCl2 solution (osmolarity = 3 mOsm/L) is hyperosmotic to 1 mM NaCl (osmolarity = 2 mOsm/L). The 1 mM glucose, 1.5 mM glucose, and 1 mM sucrose solutions are hyposmotic to 1 mM NaCl, whereas 1 mM KCl is isosmotic.

Assuming complete dissociation of all solutes, which of the following solutions would be hyperosmotic relative to 1 millimolar NaCl? Select one: a. 1.5 millimolar glucose b. 1 millimolar sucrose c. 1 millimolar glucose d. 1 millimolar CaCl2 e. 1 millimolar KCl

less than alveolar pressure Pleural pressure during inhalation is always less than alveolar or atmospheric

At the end of inhalation, with an open glottis, the pleural pressure is Select one: a. equal to atmospheric pressure b. greater than atmospheric pressure c. equal to alveolar pressure d. greater than alveolar pressure e. less than alveolar pressure

116. A 14-year-old boy has a 3-year history of type 1 diabetes mellitus. He injects himself with insulin twice daily. When he goes to summer camp, he stops Taking his insulin because he does not want to seem different from his peers. After 24 hours without his insulin dose, he develops abdominal pain and Vomiting and becomes disoriented and difficult to arouse. He is taken to the local hospital. On admission to the hospital, he is most likely to have an Increased serum glucose concentration adn which of the following findings in arterial blood?

B

119. During skeletal muscle contraction, the force exerted on the thin filaments by the cross-bridges must be greater than the force opposing shortening. Following contraction, the mechanisms that initiate force generation are turned off, and tension declines, allowing relaxation of the muscle fiber, which of The following processes most likely contributes to this relaxation after contraction?

Ca+ binding to calsequestrin

Cholinergic

Calcium entry is necessary to allow exocytosis of synaptic vesicles in what type of fibers?

decrease the intracellular [Ca2+].

Contractility is the ability to develop tension at a fixed muscle length. Factors that decrease contractility are those that ?

113. A 41-year-old woman at 31 weeks' gestation undergoes an amniocentesis because of uncontrolled hypertension. Amniotic fluid shows a decreased Lecithin-to-sphingomyelin ratio of 1.5:1 [N=3.1]. If the newborn is born at this, which of the following pulmonary findings is most likely to develop in The newborn during the first 48 hours after delivery?

Decreased functional residual capacity

Osmosis

Diffusion of water through a selectively permeable membrane

1. a 45-year-old man is diagnosed with a somatostatin producing tumor. Which of the following sets of physiological changes is most likely in this man?

E

45. A 52-year-old man is brought to the emergency department 30 minutes after the onset of chest pain and shortness of breath. He had played tennis all day, and he does not remember how much fluid he had consumed. His temperature is 36.7 C (98F) pulse is 122/min, respirations are 28/min, and blood pressure is 90/50 mm Hg. Physical examination shows dry skin and decreased capillary refill. An ECG and evaluation of cardiac enzymes shows no Abnormalities. Which of the following findings in the nephron best describes the tubular osmolality, compared with serum in this patient?

E

63. A left ventricular pressure-volume loop describing one cardiac cycle is shown. Mitral valve opening occurs at which of the following labeled points?

E

Binding of Ca++ to calmodulin Excitation-contraction coupling in skeletal muscle begins with an excitatory depolarization of the muscle fiber membrane (sarcolemma). This depolarization triggers the all-or-none opening of voltage-sensitive Na! channels and an action potential that travels deep into the muscle fiber via the T tubule network. At the Ttubule-sarcoplasmic reticulum "triad," the depolarization of the T tubule causes a conformational change in the dihydropyridine receptor and subsequently in the ryanodine receptor on the sarcoplasmic reticulum. Thelatter causes the release of Ca++ into the sarcoplasm and the binding of Ca++ to troponin C (not to calmodulin) on the actin filament.

Excitation-contraction coupling in skeletal muscle involves all of the following events EXCEPT one. Which one is this EXCEPTION? Select one: a. Depolarization of the transverse tubule (T tubule) membrane b. Increased Na+ conductance of sarcolemma c. ATP hydrolysis d. Conformational change in dihydropyridine receptor e. Binding of Ca++ to calmodulin

•Ischemia •Hypoxemia - a decrease in arterial PO2 •Hypoventilation •Diffusion defects •Ventilation defect •Perfusion defect •Right-to-left shunts •Hemoglobin (Hb)-related abnormalities •Mitochondrial causes

Hypoxia is decreased O2 delivery to the tissues-- examples of this

64. A 67-year-old woman with pernicious anemia has absent gastric parietal cells. An increase in which of the following is the most likely additional finding?

Gastrin in blood

ventricular septal defect

Holosystolic, harsh-sounding murmur Loudest at tricuspid area

Inhibit AChE

How do organophosphates affect the neuromuscular junction?

an isotonic contraction.

If the muscle generates more than 10 kg of force, then the weight moves as the muscle shortens -

an isometric contraction.

If the muscle is unable to generate more than 10 kg of force, then the muscle won't shorten -

300 mM urea Lysis of the patient's red blood cells (RBCs) was caused by entry of water and swelling of the cells to the point of rupture. Water would flow into the RBCs if the extracellular fluid became hypotonic (had a lower osmotic pressure) relative to the intracellular fluid. By definition, isotonic solutions do not cause water to flow into or out of cells because the osmotic pressure is the same on both sides of the cell membrane. Hypertonic solutions would cause shrinkage of the RBCs. 150 mM NaCl and 300 mM mannitol are isotonic. 350 mM mannitol and 150 mM CaCl3 are hypertonic. Because the reflection coefficient of urea is <1.0, 300 mM urea is hypotonic.

In a hospital error, a 60-year-old woman is infused with large volumes of a solution that causes lysis of her red blood cells (RBCs). The solution was most likely Select one: a. 150 mM NaCl b. 350 mM mannitol c. 300 mM mannitol d. 150 mM CaCl2 e. 300 mM urea

left sided heart failure

Inability to pump blood to the systemic circulation -> ↑ LV pressure -> ↑ LVEDP -> ↑ LA pressure -> ↑ pulmonary capillary pressure (Pc) -> pulmonary edema -> dyspnea Orthopnea, Paroxysmal nocturnal dyspnea, Pulmonary edema •Finally lead to ↑ pressure in RV -> ↑ pressure in RA -> ↑ pressure in systemic veins (↑ jugular venous pressure) -> pitting edema

51. A 26-year-old man is admitted to the intensive care unit because of bacterial sepsis. Laboratory studies show: Arterial blood gases [room air]: pH 7.2 PCO2 32 mm Hg [N=33-46] Po2 96 mm Hg [N=80-100] Serum HCO3- 12 mEq/L [n=22-28] Which of the following is the normal initial compensatory response to this pH?

Increased respiratory rate

46. A 25-year-old woman develops a headache, nausea, loss of appetite, and insomnia 8 hours after arriving at a ski resort at an altitude of 10,000 ft [3000m] . These symptoms resolve with acetazolamide, which she obtained from her physician before she left for her trip. Which of the following best describes The mechanism of action of acetazolamide in treating these symptoms?

Induction of metabolic acidosis, stimulating alveolar ventilation

39. A 53-year-old healthy man undergoes an exercise stress test, running on a treadmill until a maximum exertion is obtained. Which of the following statements correctly describes effects of autonomic nerve actually on the cardiovascular system in such a healthy subject?

Inhibition of parasympathetic nerves increases heart rate

123. After being given an infusion of mannitol [400mM], a healthy person is most likely to have which of the following changes in plasma osmolarity and Plasma ADH [vasopressin] concentration?

Line A

125. During an experiment of muscle contraction, intracellular calcium is decreased after a substance is administered to a muscle preparation obtained from An experimental animal. Which of the following best explains why contraction is inhibited in this case?

Myosin binding sites on actin remain covered by troponin C

90. Glycosides, like digoxin, exert a positive inotropic effect on heart muscle cells. Because of this activity they can be used clinically to increase contraction Of a failing heart. Which of the following proteins is important in the mechanism of action of digoxin on the cardiac muscle cell?

Na+/Ca2+ exchange protein

59. one-half hour after an uncomplicated vaginal delivery, a 30-year-old woman delivers the placenta but has continued heavy blood loss from vagina, Her pulse is 120/min, and blood pressure is 90/60 mm Hg. No cervical or perineal lacerations are noted. The uterus is soft, and contractions have Stopped. Medical treatment with which of the following agents is likely to be most helpful?

Oxytocin

atrial depolarization

P wave corresponds to what cardiac function?

124. A 33-year-old woman with hypertension is treated with a calcium-channel blocker that is known to slow conduction through the atrioventricular node. Which of the following components of an ECG will be affected most by this drug?

PR Interval

Iodide (I-) For iodide (I-) to be "organified" (incorporated into thyroid hor- mone), it must be oxidized to I2, which is accomplished by a peroxidase enzyme in the thyroid follicular cell membrane. Propylthiouracil inhibits peroxidase and, therefore, halts the synthesis of thyroid hormones.

Propylthiouracil can be used to reduce the synthesis of thyroid hormones in hyperthyroidism because it inhibits oxidation of Select one: a. Thyroid-stimulating hormone (TSH) b. Diiodotyrosine (DIT) c. Thyroxine (T4) d. Iodide (I-) e. Triiodothyronine (T3)

Bartter syndrome

Resorptive defect in thick ascending loop of Henle (affects Na+ /K+ /2Cl- cotransporter) - similarly to chronic loop diuretic use

Fixed splitting

Seen in ASD. ASD causes left-to-right shunt = increased RA and RV causing volumes causing increased flow through pulmonic valve such that, regardless of breath, pulmonic closure is greatly delayed.

myofilaments in each muscle fiber This increases the force that the muscle is able to generate and increases the mass of the muscle even though the number of muscle fibers is unchanged.

Strength training causes an increase in the number of?

E Fick's law of diffusion states that the rate of diffusion (D) of a gas through a biological membrane is proportional to P, A, and S, and inversely proportional to d and the square root of the MW of the gas (i.e., D ( P A S) / (d MW 2). e greater the pressure gradient there is a faster diffusion. e larger the cross-sectional area of the membrane, the higher will be the total number of molecules that can diffuse through the membrane. e higher the solubility of the gas, the higher will be the number of gas molecules available to diffuse for a given difference in pressure. When the distance of the diffusion pathway is shorter, it will take less time for the molecules to diffuse the entire distance. When the molecular weight of the gas molecule is decreased, the velocity of kinetic move- ment of the molecule will be higher, which also increases the rate of diffusion.

THe forces governing the diffusion of a gas through a biological membrane include the pressure difference across the membrane (&P), the cross-sectional area of the membrane (A), the solubility of the gas (S), the distance of diffusion (d), and the molecular weight of the gas (MW). Which of the following changes increases the diffusion of a gas through a biological membrane? Select one: a. A b. B c. C d. D e. E

impulse conduction through the AV node

The PR segment corresponds to what cardiac function?

ventricular depolarization

The QRS complex corresponds to what cardiac function?

ventricular repolarization

The T wave corresponds to what cardiac function?

medulla

The _________ produces the catecholamines, epinephrine and norepinephrine, which are amine hormones. Overproduction of catecholamines would manifest with hypertension, headaches, palpitations, flushing, and sweating.

capsule

The __________ of the nephron does not produce any hormones

Carrier-mediated transport

What type of transport has the following characteristics? •Stereospecificity •Saturation •Competition

Pneumotaxic center The pneumotaxic center transmits signals to the dorsal respiratory group that "switch off" inspiratory signals, thus controlling the duration of the filling phase of the lung cycle. is has a secondary effect of increasing the rate of breathing, because limitation of inspiration also shortens expiration and the entire period of respiration.

The basic rhythm of respiration is generated by neurons located in the medulla. Which of the following limits the duration of inspiration and increases respiratory rate? Select one: a. Ventral respiratory group b. Pneumotaxic center c. Apneustic center d. Dorsal respiratory group e. Nucleus of the tractus solitarius

Function of its postsynaptic receptor the function of a transmitter agent is solely depen- dent on the postsynaptic receptor to which it binds.

The excitatory or inhibitory action of a neurotransmitter is determined by which of the following? Select one: a. Function of its postsynaptic receptor b. Shape of the synaptic vesicle in which it is contained c. Distance between the pre- and post-synaptic membranes d. Molecular composition

Renal plasma flow If a substance is completely cleared from the plasma, the clearance rate of that substance would equal the total renal plasma flow. In other words, the total amount of substance delivered to the kidneys in the blood (renal plasma flow concentration of sub- stance in the blood) would equal the amount of that substance excreted in the urine. Complete renal clear- ance of a substance would require both glomerular filtration and tubular secretion of that substance.

The maximum clearance rate possible for a substance that is totally cleared from the plasma is equal to whichof the following? Select one: a. Urinary excretion rate of that substance b. Renal plasma flow c. GFR d. Filtration fraction e. Filtered load of that substance

Sodium When the permeability of a particular ion is increased, the membrane potential moves toward the equilibrium potential for that ion. The equi- librium potentials for chloride (-80 mV) and potassium (-92 mV) are close to the resting membrane potential, so increases in their permeability have little effect on the resting membrane potential. The equilibrium potential for sodium (+60 mV) is very far from the resting membrane potential. Thus, increasing the permeability for sodium causes a large depolarization.

The membrane potential will depolarize by the greatest amount if the membrane permeability increases for which of the following? Select one: a. Sodium and potassium b. Sodium c. Potassium and chloride d. Potassium e. Chloride

Ca2+

The table shows the concentrations of four ions across the plasma membrane of a model cell. Refer to this table when answering the following four questions If the membrane potential of this cell is -80 millivolts, the driving force is greatest for which ion? Select one: a. Na+ b. Cl- c. Ca2+ d. K+

increased after load

Ventricular pressure must rise to a greater-than-normal

Hypertrophy of individual muscle fibers Prolonged or repeated maximal contraction results in a concomitant increase in the synthesis of contractile proteins and an increase in muscle mass. This increase in mass, or hypertrophy, is observed at the level of individual muscle fibers.

Weightlifting can result in a dramatic increase in skeletal muscle mass. This increase in muscle mass is primarily attributable to which of the following? Select one: a. Fusion of sarcomeres between adjacent myofibrils b. Increase in skeletal muscle blood supply c. Increase in the number of motor neurons d. Increase in the number of neuromuscular junctions e. Hypertrophy of individual muscle fibers

Endocrine, Paracrine, Local nervous system, Autonomic nervous system

What has control of Smooth Muscle Contraction ?

J= PA(Ca-Cb)

What is the equation use to establish the net rate of diffusion across the membrane?

Hyperkalemia - no Action Potential - no muscle contraction- Muscle Weakness there are insufficient available Na+ channels to carry inward current - the upstroke of the action potential cannot occur

When cells are held in the depolarization phase or are depolarized very slowly, the inactivation gates on sodium channels automatically close, and there is no sodium current what is the result? Why?

left arm By convention, the left arm is the positive elec- trode for lead I of an EKG

When recording lead I on an EKG, the right arm is the negative electrode, and the positive electrode is the Select one: a. left leg b. right arm + left leg c. right leg d. left arm e. left arm + left leg

left leg

When recording lead II on an EKG, the positive electrode is the Select one: a. right arm + left leg b. left arm c. right leg d. left leg e. left arm + left leg

prolactin the major target tissue for prolactin is the breast, where it stimulates the secretion of milk. e other anterior pituitary hormones (adrenocorticotropic hor- mone, thyroid-stimulating hormone, follicle-stimulating hormone, and luteinizing hormone) stimulate hormones from endocrine glands.

Which of the following anterior pituitary hormones plays a major role in the regulation of a nonendocrine target gland? Select one: a. Follicle-stimulating hormone b. Prolactin c. Luteinizing hormone d. thyroid-stimulating hormone e. Adrenocorticotropic hormone

Somnolence Somnolence is a common feature of hypothyroid- ism. Palpitations, increased respiratory rate, increased cardiac output, and weight loss are all associated with hyperthyroidism

Which of the following findings is most likely in a patient who has myxedema? Select one: a. Somnolence b. Weight loss c. Increased cardiac output d. Palpitations e. Increased respiratory rate

Amino acids and glucose Both amino acids and glucose stimulate insulin secretion. Further, amino acids strongly potentiate the glucose stimulus for insulin secretion. Somatostatin inhibits insulin secretion.

Which of the following is most likely to produce the greatest increase in insulin secretion? Select one: a. Glucose and somatostatin b. Amino acids c. Amino acids and somatostatin d. Amino acids and glucose

A The proximal tubule normally absorbs approxi- mately 65% of the filtered water, with much smaller percentages being reabsorbed in the descending loop of Henle and in the distal and collecting tubules. e ascending limb of the loop of Henle is relatively imper- meable to water and therefore reabsorbs very little water.

Which part of the nephron normally reabsorbs the most water? Select one: a. A b. B c. C d. D e. E

89. The following blood gas values are measured in a resting patient: Arterial PO2 96 mm Hg [N] Arterial PCO2 40 mm Hg [N] Arterial O2 content 12.0 vol% [N=20] Mixed venous O2 content 8 vol% [N=15] These values are most consistent with which of the following?

anemia

Atrial flutter

•"sawtooth" appearance of the flutter waves

Mitral valve prolapse

•Benign, asymptomatic •mid-systolic click and late systolic murmur

Changes in PGC

•a low level of angiotensin II has a large constrictor effect on efferent arterioles, leading to a decrease in RPF and an increase in GFR •A high level of ATII in people with renal stenosis hypertension constricts efferent arteriole and keeps GFR high enough Changes in πGC are produced by changes in plasma protein concentration. Changes in PBS can be produced by obstructing urine flow (ureteral stone or constriction of a ureter)

Hyperkalaemia

•abnormally tall, tented T wave •potassium is responsible for repolarization of cardiac cells

Huntington disease

•associated with GABA deficiency in the projections from the striatum to the globus pallidus. •lack of GABA-dependent inhibition of neural pathways. •The mutation is on chromosome 4 and is dominant in inheritance, with 100% penetrance •disorder caused by trinucleotide repeat expansions >40 CAG repeats •The mutated huntingtin protein forms insoluble plaques with cross-beta structure •Huntington disease manifests with the triad of movement disorder: •chorea, •behavioral abnormalities (aggressiveness, apathy or depression), •dementia.

Atrial fibrillation

•erratic baseline with no discrete P waves •Irregularly irregular heartbeat

aortic stenosis

•increases afterload •↓ SV, ↑ ESV , ↑ Left ventricular systolic pressure •Murmur: systolic; begins after S1 with a crescendo-decrescendo in intensity •Compensatory concentric hypertrophy develops •diastolic dysfunction •angina, exertional syncope, congestive heart failure

ADH effects

•increases the water permeability of the principal cells •increases the activity of the Na+-K+-2Cl− cotransporter of the thick ascending limb - Corticopapillary Osmotic Gradient •increases urea permeability in the inner medullary collecting ducts - Corticopapillary Osmotic Gradient

Sinus Arrhythmia

•rhythm is irregular and corresponds to the respiratory cycle

Polycythemia

↑ RBC count, Htc and Hb concentration (Hypoxic erythropoietic drive - Secondary Polycythemia, Polycythemia vera)

Liddle syndrome

↑ activity of Na+ channel, ↑ Na+ reabsorption in collecting tubules - similarly to hyperaldosteronism, but aldosterone is nearly undetectable

cystic fibrosis CFTR- Cystic fibrosis transmembrane conductance regulator

-Mutation in the CFTR gene -autosomal recessive -Inability to transport chloride across epithelial cells leads to decreased secretion of chloride and increased reabsorption of sodium and water, resulting in production of thick sticky secretions in lungs and increased susceptibility to infections. characteristics of which disease?

54. Physiologists are investigating renal autoregulatory mechanisms in an animal species that closely mimics human physiology. During one of their Experiment, renal blood flow and glomerular filtration rate are measured in an anesthetized animal in response to changes in mean arterial pressure. The data they obtain is shown on the graph below. Assuming a hematocrit of .50, what is the best estimate of the filtration fraction when the mean arterial pressure is 120 mm Hg?

0.2

66. Static pressure-volume relationships for the lung and chest wall of a 30-year-old man are shown in the graph. Which of the following is the volume Remaining in his lungs at the end of a normal expiration [in L]?

2

84. Female pseudohermaphroditism is most often due to a deficiency of which of the following enzymes involved in cortisol biosynthesis?

21-hydroxylase

21. A 12-year-old boy had slowly progressive renal failure for the past 2 years. He is short and pale. Blood pressure is 150/92mm Hg. Serum calcium concentration is decreased and serum phosphate, urea nitrogen (BUN), and creatinine concentrations are increased. X-rays of the bones show subperiosteal erosions of the phalanges, osteopenia, and coarsening trabeculae. Which of the following sets of laboratory findings in serum is most likely in this patient?

E

•↑ Oil/water partition coefficient = ↑ permeability •↓ Radius (size) of the solute = ↑ permeability •↓ Membrane thickness = ↑ permeability

How do the following affect membrane permeability? •↑ Oil/water partition coefficient •↓ Radius (size) of the solute •↓ Membrane thickness

Osmolarity= g x C

How do you calculate osmolarity?

Negative ion X will enter the cell if it is a cation (+) Positive ion X will leave the cell if it is a cation (+)

How does an ion move under physiological conditions?

8. During an experiment, the following data were obtained from an anesthetized dog: Mean glomerular capillary hydrostatic pressure = 45 mm Hg Mean bowman space hydrostatic pressure = 12 mm Hg Mean glomerular capillary oncotic pressure = 23 mm Hg Mean bowman space oncotic pressure = 0 mm Hg Coefficient of filtration = 3.3 [mL/min]/mm Hg Renal blood flow = 200 mL/min Hematocrit = 40% Which of the following best represents the glomerular filtration rate [in mL/min] in this animal?

30

24. A 25-year-old man has a respiratory frequency of 10/min, a tidal volume of 550mL and deadspace of 150. Which of the following is his alveolar ventilation (in L/min)?

4.0

4. A 21-year-old woman has a mechanical aortic valve implanted after resolution of severe subacute bacterial endocarditis. She begins systemic Anticoagulation with warfarin. Warfarin prevents cerebrovascular embolism by inhibition of which of the following?

carboxylation of coagulation factors

80. A 41-year-old male suffering from unstable angina is undergoing cardiac testing. At rest, his heart rate is 70 beats per minute. His left ventricular end-Diastolic volume is estimated to be 150 mL, while his end systolic volume is 80 mL. What is his estimated cardiac output?

4900/mL/min

38. Motility recordings in a patient with signs of bacterial overgrowth of the small intestine indicate an abnormal pattern of motility in the fasting state that is characterized by a lack of the normal periodic bursts of gastric and intestinal contractions. This patient is likely to demonstrate abnormal secretion of which of the following hormones?

Motilin

Gastrocolic reflex The gastrocolic reflex occurs when distension of the stomach (gastro) stimulates mass movements in the colon (colic). All of the gut reflexes are named with the anatomical origin of the reflex as the prefix followed by the name of the gut segment in which the outcome of the reflex is observed, that is, the gastrocolic reflex begins in the stomach and ends in the colon. The duodenocolic reflex has a similar function to the gastrocolic reflex. When the duodenum is distended, nervous signals are transmitted to the colon, which stimulates mass movements. The enterogastric reflex occurs when signals originating in the intestines inhibit gastric motility and gastric secretion. The intestino- intestinal reflex occurs when overdistension or injury to a bowel segment signals the bowel to relax. The rectosphincteric reflex, also called the defecation reflex, is initiated when feces enters the rectum andstimulates the urge to defecate.

54-year-old woman eats a healthy meal. Approximately 20 min later the woman feels the urge to defecate. Which of the following reflexes results in the urge to defecate when the stomach is stretched? Select one: a. Rectosphincteric b. Gastrocolic reflex c. Intestino-intestinal reflex d. Enterogastric reflex e. Duodenocolic reflex

B Both the lung and thoracic cage are elastic. Under normal conditions, the elastic tendency of the lungs to collapse is exactly balanced by the elastic tendency of the thoracic cage to expand. When air is introduced into the pleural space, the pleural pressure becomes equal to atmospheric pressure—the chest wall springs outward and the lungs collapse.

A 34-year-old male sustains a bullet wound to the chest that causes a pneumothorax. Which of the following best describes the changes in lung volume and thoracic volume in this man, compared to normal? Select one: a. A b. B c. C d. D e. E f. F

Hemophilia A

most common type of hemophilia (83% of all cases) due to a deficiency of factor VIII

4.5 The forced vital capacity (FVC) is equal to the difference between the total lung capacity (TLC) and the residual volume (RV). THe TLC and RV are the points of intersection between the abscissa and flow-volume curve, that is, TLC = 5.5 L and RV = 1.0 L. THerefore, FVC = 5.5 - 1.0 = 4.5L.

A 45-year-old man inhaled as much air as possible and then expired with a maximum eff ort until no more air could be expired. TH is produced the maximum expiratory flow-volume curve shown in the following diagram. What is the forced vital capacity of this man (in liters)? Select one: a. 3.5 b. 2.5 c. 5.5 d. 1.5 e. 4.5

69. The figure below shows a lead II electrocardiogram from a normal 30-year-old female at rest. If a beta-adrenergic antagonist such as isoproterenol is Administered intravenously to this woman, what will be her resulting heart rate in beats per minute?

90

120. A 35-year-old woman is brought to the emergency department by her husband because she passed out while washing dishes. The patient says she Began to feel weak and dizzy but does not remember anything else. While the nursing staff is checking her vital signs and drawing blood, the husband Tells the physician that the patient has bulimia nervosa and that she has been binging more frequently over the past 3 weeks. He suspects that she has Been vomiting. Which of the following patterns of abnormal laboratory test results most likely indicates recurrent vomiting in this patient?

A

30. A 60-year-old comes to the physician because of a 6-month history of progressive shortness of breath. He has smoked 2 packs of cigarettes daily for 40 years. His respirations are 22/min. Physical examination shows hyperresonance to percussion. Laboratory studies show hypoxia and hypercapnia. His gas exchange rate is 15% of that of a healthy individual. A CT scan of the chest shows numerous obstructed small bronchioles with air trapping. In alveoli beyond the obstructions which of the following points on the graph shown best represents the relationship between PO2 and PCO2 if the patient is breathing room at sea level?

A

112. The following pulmonary pressures [in mmHg] were measured in an animal Hydrostatic capillary pressure 12 Oncotic capillary pressure 20 Hydrostatic interstitial pressure 5 Oncontic interstitial pressure 15 The filtration coefficient of the pulmonary microvasculature is 1 mL/min/100 g tissue/mm Hg pressure. And the reflection coefficient for protein 1. Which of the following best represents the magnitude and direction of fluid flux in this animal?

A 2 capillary to interstitial space

H The oxygen carrying capacity of the blood is reduced in an anemic person, but the arterial PO2 and oxygen saturation of hemoglobin are both normal. e decrease in arterial oxygen content is compensated for by an increase in the extraction of oxygen from hemoglobin, which reduces the Po2 of the venous blood. e unload- ing of oxygen at the tissue level is enhanced by increased levels of 2,3 diphophosphoglycerate (2,3 DPG) in an anemic patient because 2,3 DPG causes a right-shift of the oxygen-hemoglobin dissociation curve.

A 34-year-old woman is anemic with a blood hemoglobin concentration of 7.1 g/dL. Which of the following sets of changes has occurred in this woman, compared to normal? Select one: a. A b. B c. C d. D e. E f. F g. G h. H i. I

Glucose-dependent insulinotropic peptide (GLIP) GLIP is the only gastrointestinal hormone released by all three major foodstuffs (fats, proteins, and carbohydrates). The presence of fat and protein in the small intestine stimulates the release of CCK, but carbohydrates do not stimulate its release. The presence of protein in the antrum of the stomach stimulates therelease of gastrin, but fat and carbohydrates do not stimulate its release. Fat has a minor effect to stimulatethe release of motilin and secretin, but neither hormone is released by the presence of protein or carbohydrate in the gastrointestinal tract.

A 10-year-old boy consumes a cheeseburger, fries, and chocolate shake. The meal stimulates the release of several gastrointestinal hormones. The presence of fat, carbohydrate, or protein in the duodenum stimulates the release of which of the following hormones from the duodenal mucosa? Select one: a. Secretin b. Cholecystokinin (CCK) c. Glucose-dependent insulinotropic peptide (GLIP) d. Motilin e. Gastrin

increase in nerve cell potassium conductance caused by membrane depolarization Electrically excitable gates are those that respond to a change in membrane potential. The most notable electrically excitable gates are those on the sodium and potassium channels that produce the nerve action potential. The potassium channel gate is opened by depolarization. Ven- tricular muscle SR releases its calcium in response to an increase in intra- cellular calcium. The gates opened by ACh are chemically excitable gates. In rods, sodium channels are closed when cGMP is hydrolyzed. Electrically excitable gates do not regulate the active transport of glucose.

A 13-year-old boy on the junior high wrestling team experiences attacks of proximal muscle weakness that last from 30 minutes to as long as 4 hours following exercise and fasting. The trainer attributed it to the symptoms of fatigue, but his mother recalled having similar symptoms when she was dieting. Genetic testing revealed an inherited channelopathy. Electrically excitable gates are normally involved in which of the following? Select one: a. The depolarization of the end-plate membrane by acetylcholine b. Release of calcium from ventricular muscle sarcoplasmic reticulum c. Increase in nerve cell potassium conductance caused by membrane depolarization d. Transport of glucose into cells by a sodium-dependent, secondary active transport system e. Hyperpolarization of rods by light

Ejecting blood at a reduced rate

A 14-year-old boy is in cardiac arrest after being hit with a baseball in the chest above the left ventricle. This devastating occurrence, called commotio cordis, is very rare, since the impact must occur during the ascending phase of the T wave. Which of the following events is also occurring at this time? Select one: a. Opening the mitral valve b. Rapidly filling the left ventricle c. Slowly filling the left ventricle d. Ejecting blood at a reduced rate e. Increasing left ventricular pressure

Motilin Motilin is the gastroin- testinal peptide hormone associated with the initiation of migrating motor complexes during the interdigestive period. The hormone stimulates increased contractions by a direct action on smooth muscle and by activa- tion of excitatory enteric nerves. Erythromycin belongs to the group of macrolide antibiotics and also shows an ability to excite motilin-like recep- tors on enteric nerves and smooth muscle. As a result, a common side effect of the antibiotic is abdominal cramping and diarrhea.

A 17-year-old male who is being treated with the macrolide antibiotic erythromycin complains of nausea, intestinal cramping, and diarrhea. The side effects are the result of the antibiotic binding to receptors on GI tract enteric nerves and smooth-muscle cells that recognize which gastrointestinal hormone? Select one: a. Cholecystokinin b. Motilin c. Secretin d. Gastrin e. Enterogastrone

Gastrin only Gastrin has a critical role to stimulate mucosal growth throughout the gastrointestinal system.

A 19-year-old man is fed intravenously for several weeks following a severe automobile accident. The intravenous feeding leads to atrophy of the gastrointestinal mucosa most likely because the blood level of which of the following hormones is reduced? Select one: a. Cholecystokinin only b. Gastrin and cholecystokinin c. Gastrin and secretin d. Secretin only e. Gastrin only f. Secretin and cholecystokinin

C A Pseudomonas infection can increase the capillary permeability in the lungs and elsewhere in the body, which leads to excess loss of plasma proteins into the interstitial spaces. is leakage of plasma proteins from the vasculature caused the plasma colloid osmotic pressure to decrease from a normal value of about 28 mm Hg to 19 mm Hg. e capillary hydrostatic pressure remained at a normal value of 7 mm Hg, but it can sometimes increase to higher levels, exacerbating the formation of edema. e interstitial fluid hydro- static pressure has increased from a normal value of about 5 mm Hg to 1 mm Hg, which tends to decrease fluid loss from the capillaries. Excess fluid in the inter- stitial spaces (edema) causes lymph flow to increase.

A 19-year-old man suff ers a full-thickness burn over 60% of his body surface area. A systemic Pseudomonas aeruginosa infection occurs and severe pulmonary edema follows 7 days later. Data collected from the patient follow: plasma colloid osmotic pressure, 19 mm Hg; pulmonary capillary hydrostatic pressure, 7 mm Hg; and interstitial fluid hydrostatic pressure, 1 mm Hg. Which of the following sets of changes has occurred in the lungs of this patient as a result of the burn and subsequent infection? Select one: a. A b. B c. C d. D e. E

Brush border lactase deficiency Patients with a lactase deficiency cannot digest milk products containing lactose (milk sugar). The operons of gut bacteria quickly switch over to lactose metabolism, which results in fermentation that produces copious amounts of gas (a mixture of hydrogen, carbon dioxide, and methane). This gas, in turn, may cause a range of abdominal symptoms, including stomach cramps, bloating, and flatulence. "e gas is absorbed by blood (especially in the colon), and exhaled from the lungs.

A 19-year-old woman visits her physician because of nausea, diarrhea, light headedness, and flatulence. The physician administers 50 g of oral lactose at time zero, and measures breath hydrogen every 30 min for 3 hr using a hand-held monitor. The results are shown. Which of the following best describes this patient's condition? Select one: a. Increased pancreatic lactase b. Brush border lactase deficiency c. No digestive abnormality d. Brush border lactase excess e. Decreased pancreatic lactase

A The arterial baroreceptors are activated in response to a fall in arterial pressure. During hemorrhage, the fall in arterial pressure at the level of the baroreceptors results in enhanced sympathetic outflow from the va- somotor center and a decrease in parasympathetic nerve activity. e increase in sympathetic nerve activ- ity leads to constriction of peripheral blood vessels, increased total peripheral resistance, and a return of blood pressure toward normal. e decrease in para- sympathetic nerve activity and sympathetic outflow would result in an increase in heart rate.

A 22-year-old man enters the hospital emergency room after severing a major artery in a motorcycle accident. It is estimated that he has lost approximately 700 ml of blood. His blood pressure is 90/55 mm Hg. Which of the following sets of changes would be expected in response to hemorrhage in this man? Select one: a. B b. D c. A d. H e. C f. G g. F h. E

0.50 mm Hg/ml/min Vascular resistance = arterial pressure - venous pressure / blood flow. In this example, arterial pressure is 130 mm Hg, venous pressure is 5 mm Hg, and blood flow is 250 ml/min. THus, vascular resistance 125 / 250, or 0.50 mm Hg/ml/min.

A 22-year-old man has a muscle blood flow of 250 ml/ min and a hematocrit of 50. He has a mean arterial pressure of 130 mm Hg, a muscle venous pressure of 5 mm Hg, and a heart rate of 80 beats/min. Which of the following is the approximate vascular resistance in the muscle of this man? Select one: a. 1.00 mm Hg/ml/min b. 0.20 mm Hg/ml/min c. 0.50 mm Hg/ml/min d. 2.50 mm Hg/ml/min e. 0.10 mm Hg/ml/min

-The amount of sodium entering the nerve with each action potential increases -The membrane potential becomes more positive In order for propagation of an action potential to occur, the depolarization produced by one action poten- tial must depolarize the adjacent patch of excitable membrane to the threshold level. In demyelinating diseases, such as multiple sclerosis, too much charge leaks from the membrane and as a result, not enough charge is available to bring the next patch of membrane to threshold. Increasing the duration of the action potential increases the amount of charge enter- ing the cell and therefore increases the probability that the next patch of excitable membrane will be depolarized to threshold. Increasing the dura- tion of the refractory period will not affect the amount of charge entering the cell. Depolarizing the membrane and increasing potassium conduc- tance will make it more difficult to produce an action potential. If mem- brane capacitance is increased, the amount of charge required to excite the next patch of membrane will be increased.

A 19-year-old woman with a history of diplopia and paresthesia is diagnosed with multiple sclerosis (MS). MS is a demyelinating disease characterized by a failure of nerve conduction. Immersion of an affected limb in a cold bath restores nerve conduction in many of these patients. The explanation often cited for this effect is that cold increases the duration of the action potential. Which of the following best explains why increasing the duration of the action potential can restore nerve conduction in patients with MS? Select one: a. The amount of sodium entering the nerve with each action potential increases b. The potassium conductance of the membrane is increased c. The capacitance of the nerve fiber membrane is increased d. The membrane potential becomes more positive e. The duration of the refractory period is increased

Factor VIII A young man with bleeding disorders and a history of bleeding disorders in the males of his family would lead one to suspect hemophilia A, a deficiency of factor VIII.

A 2-year-old boy bruises easily and has previously had bleeding gums. ! e maternal grandfather has a bleeding disorder. His physical examination shows several small bruises on the legs. Of which coagulation factor would you suspect this patient to be deficient? Select one: a. Factor VIII b. Factor X c. Prothrombin activator d. Factor II

Point B

A 20-year-old man presents to the emergency room with a laceration in his left leg. He fell from his bike while mountain biking. There is a 4-centimeter laceration on his left shin. The wound is sterilized. Prior to suturing, lidocaine is injected into subcutaneous tissue surrounding the laceration. Lidocaine will prevent normal ion function at which point in the action potential below? Select one: a. D b. A c. C d. B

C A reduction in plasma protein concentration to 3.6 g/dL would increase the capillary filtration rate, thereby raising interstitial fluid volume and interstitial fluid hydrostatic pressure. e increased interstitial fluid pressure would, in turn, increase the lymph flow rate and reduce the interstitial fluid protein concentra- tion ("washout" of interstitial fluid protein).

A 20-year-old woman arrives at your offi ce complaining of rapid weight gain and marked fluid retention. Her blood pressure is 105/65 mm Hg, her plasma protein concentration is 3.6g/dL (normal = 7.0), and she has no detectable protein in her urine. Which of the following changes would you expect to find, compared with normal? Select one: a. A b. B c. C d. D e. E

Type B only Since the plasma contains antibodies the wrong plasma could contain antibodies against the B antigen. therefore, he could receive B plasma (containing anti-A antibodies) or AB (containing neither anti-A or anti-B antibodies.)

A 21-year-old female, blood type B, is undergoing surgery. Her platelet count is 75,000/!l. She will need platelet infusions before and during surgery. Which of the following blood types would be used to collect platelets that are compatible with the patient? Select one: a. Types B and O b. Type A only c. Type O only d. Type B only e. Types A, B, and AB only f. Types A and B g. Types A and B only

2 The intersection of cardiac output and venous return curves represents the equilibrium function of the heart. In a normal person, exercise will cause an increase in both cardiac output and venous return leading to a new equilibrium at point 2. This patient is a healthy athlete with a provided equilibrium at point 1. During exercise, increased contractility (+ inotropy) leads to increased stroke volume and heart rate resulting in increased cardiac output. This is represented by a shift of the cardiac output curve up and to the left. Illustration A shows the annotated completion of Figure A. Notice that the positive inotropy curve in green and the positive venous return curve in red represent the physiological increase in blood flow during exercise. Incorrect Answers: Answer 1: This is the resting state for a healthy individual. The cardiovascular system undergoes changes during exercise in healthy individuals as explained in the discussion. Answer 3: This state represents an increase in TPR and a decrease in overall cardiac output. This can be seen in the acute stages of massive hemorrhage with decompensated shock physiology. Answer 4: This state represents negative inotropy. This can happen with narcotics that increase venous capacitance, decreasing mean circulatory filling pressure, and decreasing venous return. Answer 5: This is the x-intercept of the graph and represents mean circulatory filling pressure

A 21-year-old male comes into the physician for a yearly physical. He is a swimmer with no significant past medical history. His baseline cardiac output and venous return curves are shown in Figure A. Assuming that he starts at position 1, which of the following points would most likely represent his cardiac output and venous return curves during one of his swim practices? Select one: a. 2 b. 1 c. 4 d. 5 e. 3

Somatostatin

A 21-year-old male presents to his family physician with loss of vision in his right eye. On exam, he is noted to have a large tongue and coarse facial features. He states that he has grown over a foot in the past year and is now 7 feet 2 inches tall. Laboratory work shows that he has an impaired glucose tolerance, elevated serum IGF-1, and a failure to suppress serum growth hormone following an oral glucose tolerance test. The medication most commonly used to control this patient's condition is an analogue of which hormone? Select one: a. Glucagon b. Somatostatin c. Thyroid-stimulating hormone (TSH) d. Insulin e. Estrogen

D It is important for the blood to be distributed to those segments of the lungs where the alveoli are best oxygenated. When the oxygen tension of the alveoli decreases below normal, the adjacent blood vessels con- strict causing their resistance to increase as much as fivefold at extremely low oxygen levels. is is opposite to the effect observed in systemic vessels, which dilate in response to low oxygen (i.e., resistance decreases).

A 32-year-old man drives to the top of Pikes Peak where the oxygen tension is 85 mm Hg. Which of the following best describes the effects of a hypoxic environment on the pulmonary and systemic vascular resistances? Select one: a. A b. B c. C d. D e. E f. F g. G h. H i. I

Hyperpolarization of the resting membrane potential The resting membrane potential is especially sensitive to changes in extracellular potassium concentration because the cell membrane is essentially permeable to potassium. Recall that the resting membrane potential of a cell is closest to the equilibrium potential (Nernst potential) of the ion with the highest membrane conductance (permeability). Also, recall that the equilibrium potential for potassium is negative because the concentration of potassium is higher inside the cell compared with outside the cell (thus potassium ions tend to diffuse out of the cell, and this removal of positive charges from the cell interior leads to a net negative charge inside the cell). When the extracellular concentration of potassium is decreased, the transmembrane potassium ion gradient is increased, which causes the potassium equilibrium potential to become more negative. When the potassium equilibrium potential becomes more negative, the membrane potential becomes more negative, or hyperpolarized. The net driving force for an ion is the difference between the membrane potential of the cell and the equilibrium potential of the ion. For example, if the membrane potential were -90 mV and the potassium equilibrium potential were -94 mV, the net driving force for potassium ions (choice A) would be 4 mV. Decreasing the extracellular potassium concentration will decrease (hyperpolarize) the membrane potential, but the decrease in membrane potential will not be as great as the decrease in potassium equilibrium potential (since potassium conductance is not infinitely high). Therefore, the net driving force for potassium will increase slightly. Again, the membrane potential is more negative (hyperpolarized), not less negative (depolarized) (choice B) Decreasing extracellular potassium concentration would tend to decrease (not increase; choice D) intracellular potassium concentration. Again, the potassium equilibrium potential becomes more negative (not less negative; choice E) when the extracellular potassium concentration decreases

A 22-year-old woman decides to lose weight on a diet suggested by an anorexic friend. She loses about 30 pounds in 45 days, but her serum potassium falls to a level of 2.1 mEq/L (normal: 3.5-5.0 mmol/L). Which of the following changes is most likely to occur in this young woman? Select one: a. Potassium equilibrium potential is less negative b. Hyperpolarization of the resting membrane potential c. Increased intracellular potassium concentration d. Depolarization of the resting membrane potential e. A decreased net driving force for potassium from cells

Increased central venous pressure Net filtration from systemic capillaries is dependent on the Starling forces and capillary permeability. The equation is Net filtration = Kf [(Pcapillary - Ptissue) - (πcapillary - πtissue)], where Kf is the filtration coefficient of the membrane, and is directly proportional to capillary permeability, Pcapillary and Ptissue are the hydrostatic pressures in the capillary and tissue (interstitial space), respectively, and πcapillary and πtissue are the osmotic (colloid oncotic) pressures in the capillary and interstitial space, respectively. Increasing central venous pressure increases the capillary hydrostatic pressure (Pcapillary), which increases the filtration of fluid from the systemic capillaries, leading to edema. All of the other choices will cause a decrease in filtration.

A 22-year-old woman is hospitalized with a history of respiratory distress, fever, and fatigue. ST segment and T wave abnormalities suggest myocarditis, which is attributed to an acute viral origin. Over the next several days, significant peripheral edema develops. The edema is most likely caused by which of the following? Select one: a. Increased plasma protein concentration b. Decreased capillary permeability c. Decreased arterial pressure d. Increased lymphatic flow e. Increased central venous pressure

Valsalva maneuver This patient has a tall, slender physique and a family history of a father who died at age 53 from an aortic dissection. Her appearance and family history suggest Marfan syndrome. [Other findings that would be suggestive of Marfan syndrome include arachnodactyly (long and slender fingers, shown in the image) and ocular lens dislocation. Marfan syndrome is associated with a high prevalence of mitral valve prolapse (MVP) is classically described as a midsystolic click followed by a crescendo-decrescendo murmur heard best at the apex. Maneuvers that decrease venous return (eg, Valsalva maneuver, standing) and volume of the left ventricle worsen the prolapse. When these maneuvers are performed, the crescendo-decrescendo murmur heard in MVP increases in intensity and duration, and the midsystolic click occurs earlier. Aortic insufficiency (AI) is another valvular lesion that may occur in patients with Marfan syndrome, secondary to aortic root dilatation. AI would manifest with a diastolic decrescendo murmur that is louder on expiration and accentuated by hand grip.] Inspiration increases venous return to the right atrium and would potentially decrease murmur intensity. Lying down increases venous return to the right atrium and could decrease the murmur. The Müller maneuver involves asking the patient to inhale against a closed mouth and nose, and it can be used to detect collapsed upper airways. Rapid squatting heightens preload by increasing the return of blood to the heart and boosts afterload via constriction of peripheral vessels. This decreases the MVP murmur.

A 22-year-old woman who is a medical student presents to a physician as a new patient. During the initial visit, the student notes that she has no health complaints. The patient's family history includes a healthy mother and brother, but her father died at age 53 from an aortic dissection. Physical examination indicates that the patient is 187.96 cm (6'2") tall, and weighs 61 kg (135 lb). Physical examination reveals chest asymmetry. Pulse is 64/min and a blood pressure is 115/70 mm Hg. An auscultation presents a midsystolic click followed by a crescendo-decrescendo murmur heard best at the apex Which of the following physical maneuvers can the patient perform to accentuate the cardiac auscultation findings? Select one: a. Inspiration b. Rapid squatting c. Valsalva maneuver d. Lying down e. Müller maneuver

Anemia The magnitude of the cardiac output is regulated to maintain an adequate blood pressure and to deliver an adequate supply of oxygen to the tissues. In anemia, a greater cardiac output is required to supply oxygen to the tissues because the oxygen-carrying capacity of the blood is reduced. The reduced blood viscos- ity increases the velocity and thus the turbulence of the blood flow, which makes systolic murmurs common in anemic patients. In aortic regurgitation, the stroke volume will be increased, but a portion of the blood ejected by the heart will return to the heart during diastole. Thus, the output delivered to the tissues does not increase despite the fact that the blood ejected by the heart has increased. In hypertension, third-degree heart block, and cardiac tamponade (decreased filling of the heart due to accumulation of fluid within the pericardium), cardiac output will be normal or reduced.

A 23-year-old female presents with fatigue and is found to have a systolic murmur and higher than normal cardiac output. The differential diagnosis based on these findings includes which of the following? Select one: a. Anemia b. Aortic regurgitation c. Hypertension d. Mitral valve prolapse e. Mitral stenosis

Intracellular volume

A 23-year-old man is brought to the Emergency Department after collapsing during basketball practice. On admission he is lethargic and appears confused. His coach reports that it was hot in the gym and he was drinking a lot of water during practice. An increase in which of the following is the most likely cause of his symptoms? Select one: a. Plasma volume b. Intracellular tonicity c. Extracellular tonicity d. Extracellular volume e. Intracellular volume

E All of the GI hormones are released following a meal and all have physiological effects.

A 23-year-old medical student consumes a cheeseburger, fries, and chocolate shake. Which of the following hormones produce physiological effects at some point over the next several hours? Select one: a. B b. D c. C d. E e. A

C Because the blood that perfuses the pulmonary capillaries is venous blood returning to the lungs (i.e., mixed venous blood) from the systemic circula- tion, it is the gases in this blood with which the alveo- lar gases equilibrate. erefore, when an airway is blocked, the alveolar air equilibrates with the mixed venous blood and the partial pressures of the gases in both the blood and alveolar air become identical.

A 23-year-old medical student has mixed venous oxygen and carbon dioxide tensions of 40 mm Hg and 45 mm Hg, respectively. A group of alveoli are not ventilated in this student because mucus blocks a local airway. What are the alveolar oxygen and carbon dioxide tensions distal to the mucus block (in mm Hg)? Select one: a. A b. B c. C d. D e. E

Cardiac output is higher than normal Distributive shock is char- acterized by a decreased peripheral resistance and a high cardiac output. The decrease in peripheral resistance is so great that mean blood pressure falls below normal. Hypovolemic shock is caused by a decrease in circulat- ing blood volume and pressure. In both types of shock, the baroreceptor reflex increases ventricular contractility and heart rate. Also, in both types of shock, blood is shunted away from the kidney, decreasing renal blood flow and glomerular filtration. As a result, plasma creatinine levels rise.

A 37-year-old patient is brought to the Emergency Department in shock. Which of the following is a reason to direct treatment toward destributive shock rather than hypovolumic shock? Select one: a. Ventricular contractility is greater than normal b. Heart rate is greater than normal c. Serum creatinine is elevated d. Total peripheral resistance is greater than normal e. Cardiac output is higher than normal

Duodenum Inflammation of the duodenum may lead to increased acid output, hypocalcemia, and microcytic anemia. Increased basal and maxi- mal acid outputs may result from excessive stimulation of the parietal cell (e.g., hypergastrinemia) or reduced inhibitory feedback (i.e., reduced effect of enterogastrone and the enterogastric reflex). The latter may occur when the proximal small intestine is inflamed. Although calcium is absorbed along the entire length of the small intestine, it is absorbed primarily in the duodenum. Similarly, iron is absorbed primarily in the duodenum. Microcytic anemia is the result of reduced stores of iron, the most common anemia. Glucose-6-phosphatase deficiency is the most common metabolic disorder of red blood cells, and is also associated with a microcytic anemia, as is a-thalassemia.

A 23-year-old woman complains of abdominal cramps and bloating that are relieved by defecation. Subsequent clinical evaluation reveals an increased maximal acid output, decreased serum calcium and iron concentrations, and microcytic anemia. Inflammation in which area of the GI tract best explains these findings? Select one: a. Ileum b. Duodenum c. Colon d. Jejunum e. Stomach

A decreased glomerular filtration rate Urea is synthesized primarily in the liver. Its excretion is depen- dent on its concentration in plasma and the glomerular filtration rate (GFR) in the kidney. Approximately 50 to 60% of filtered plasma urea is passively reab- sorbed in the proximal tubule at normal GFR. In renal insufficiency, in which GFR is decreased, less urea is filtered and therefore less urea is excreted. The decreased excretion of urea results in an increase in its plasma concentration.

A 24-year-old man with a history of renal insufficiency is admitted to the hospital after taking a large amount of ibuprofen. His BUN is 150 mg/dL. This patient's high serum urea nitrogen was most likely caused by which of the following? Select one: a. An increased synthesis of urea by the liver b. An increased reabsorption of urea by the proximal tubules c. A decreased glomerular filtration rate d. A decreased secretion of urea by the distal tubules e. An increased renal blood flow

A In patent ductus arteriosus, a large quantity of the blood pumped into the aorta by the left ventricle immediately flows backward into the pulmonary artery and then into the lung and left atrium. e shunting of blood from the aorta results in a low diastolic pressure, while the increased inflow of blood into the left atrium and ventricle increases stroke volume and systolic pressure. e combined increase in systolic pressure and decrease in diastolic pressure results in an increase in pulse pressure.

A 24-year-old woman delivers a 6-lb, 8-oz female baby. The newborn is diagnosed as having patent ductus arteriosus. Which of the following sets of changes would be expected in this baby? Select one: a. A b. G c. E d. H e. F f. D g. B h. C

Delayed closing of the pulmonic valve The second heart sound (S2) is associated with the closing of the aortic and pulmonic valves. The aortic valve normally closes slightly before the pulmonic valve, resulting in a splitting of the second heart sound into two components. During inspiration, the closing of the pulmonic valve is delayed, resulting in a prolongation of the interval between the two components of the second heart sound. During inspiration, the preload on the right heart is increased, resulting in a larger stroke volume, which causes the delay in the closing of the pulmonic valve. Closure of the mitral valve and tricuspid valves are associated with the first heart sound (S1). Heart rate is higher during inspiration than during expiration.

A 24-year-old woman undergoes an annual physical examination for participation on the varsity track team at her college. While auscultating her heart sounds, the sports medicine physician instructs the woman to take in a deep inspiration. During this maneuver, he detects splitting of the second heart sound. Which of the following is the mechanism underlying this finding? Select one: a. A decrease in heart rate b. An increased left ventricular stroke volume c. Delayed opening of the mitral valve d. Delayed closing of the aortic valve e. Delayed closing of the pulmonic valve

Decreased bile salt pool size Steatorrhea is defined as excess loss of fat in the stool. Numerous pathophysiological situations can cause the loss of excess fat in the stool including a decrease in bile acid pool size, inactivation or decreased intraluminal concentration of pancreatic lipase in the small intestine, and decreased intestinal absorptive surface area. A decrease in bile acid pool size results in an increased delivery of fats into the colon, which in turn inhibits fat absorption and promotes water secretion.

A 26-year-old male presents to the emergency room with a 48-hour bout of diarrhea with steatorrhea. Which of the following best accounts for the appearance of excess fat in the stool? Select one: a. Decreased bile salt pool size b. Decreased secretion of intrinsic factor c. Decreased gastric acid secretion d. Delayed gastric emptying e. Decreased gastric accommodation

Electroneutral NaCl transport Diarrhea is the abnormal passage of fluid or semisolid stool with increased fre- quency. The general approach to the primary evaluation of patients with diarrhea is differentiating between an infectious versus noninfectious etiol- ogy. Although sodium is absorbed from the small intestine by several mechanisms, bacterial toxins specifically inhibit neutral NaCl absorption. In addition, the toxins augment diarrhea by increasing salt and water secre- tion by intestinal crypt cells. Oral rehydration involves utilizing the sodium-glucose-coupled cotransport pathway.

A 27-year-old female comes to the emergency room because of a 2-day bout of profuse watery diarrhea. Physical examination reveals dry lips and oropharynx. The patient is diagnosed with acute secretory diarrhea and dehydration, likely due to Escherichia coli. Which of the following sodium reabsorptive pathways is inhibited by the enterotoxin? Select one: a. Sodium-bile salt cotransport b. Electroneutral NaCl transport c. Electrogenic sodium diffusion d. Sodium-hydrogen countertransport e. Sodium-glucose-coupled cotransport

C Achalasia is a condition in which the lower esophageal sphincter (LES) fails to relax during swallowing. As a result, food swallowed into the esophagus then fails to pass from the esophagus into the stomach. Trace C shows a high, positive pressure that fails to decrease after swallowing, which is indicative of achalasia.Trace A shows a normal pressure tracing at the level of the LES reflecting typical receptive relaxation in response to the food bolus. Trace E is similar to trace C, but the pressures are subatmospheric. Subatmospheric pressures occur only in the esophagus where it passes through the chest cavity.

A 33-year-old man comes to the physician because his chest hurts when he eats, especially when he eats meat. He also belches excessively and has heartburn. His wife complains about bad breath. X-ray shows a dilated esophagus. Which one of the pressure tracings was most likely taken at the lower esophageal sphincter of this patient before and after swallowing (indicated by arrow)? The dashed line represents a pressure of 0 mm Hg. Select one: a. C b. D c. A d. E e. B

Contractile activity is initiated in response to bowel wall distention Contractile activity in the small intestine is initiated in response to distention of the bowel wall. Three types of smooth muscle contractions contribute to small intestinal motility—peristalsis, segmental contractions, and tonic contrac- tions. A fourth type of contraction, peristaltic rushes, are very intense peri- staltic waves that may occur in intestinal obstruction. The basal electrical rhythm (BER) are the spontaneous rhythmic fluctuations in membrane potential in the smooth muscle along the GI tract. The BER itself rarely causes muscle contraction, but contractions only occur during the depo- larizing phase of BERs, which function to coordinate the various types of contractile activity. The BER is initiated by the interstitial cells of Cajal, which, in the small intestine, are located in the outer circular muscle layer near the myenteric plexus. There are an average of ~12 BER cycles/min in the duodenum and proximal jejunum and 8/min in the distal ileum. During fasting between periods of digestion, cycles of motor activity, called migrat- ing motor complexes (MMC), migrate from the stomach to the distal ileum. The MMCs immediately stop with ingestion of food. After vagotomy, contractile activity becomes irregular and chaotic.

A 27-year-old female medical student with irritable bowel syndrome (IBS) has an alteration in intestinal motility resulting in fluctuating constipation and diarrhea. Her condition has worsened in the past month as the date she has scheduled for her licensure examination approaches. Which of the following statements about small intestinal motility is correct? Select one: a. Contractile activity is initiated in response to bowel wall distention b. Migrating motor complexes occur during the digestive period c. Vagotomy abolishes contractile activity during the digestive period d. Peristalsis is the only contractile activity that occurs during feeding e. Contractile frequency is constant from duodenum to terminal ileum

2.0 the expiratory reserve volume (ERV) is the maxi- mum extra volume of air that can be expired by force- ful expiration after the end of a normal tidal expira- tion. ERV is equal to the difference between the functional residual capacity (FRC, 3 L) and the residual volume (RV, 1 L). Although neither FRC nor RV can be determined from a spirogram alone, the relative differ- ences between these two volumes can still be deter- mined from a spirogram and thus can be used to calculate ERV.

A 27-year-old man is breathing quietly. He then inhales as much air as possible and exhales as much air as he can, producing the spirogram shown in the previous figure. What is his expiratory reserve volume (in liters)? Select one: a. 3.0 b. 3.5 c. 2.0 d. 2.5 e. 4.0

Polymorphonuclear cells

A 29-year-old man presents to the doctor's office with cough, fever, malaise and chills. A bacterial pneumonia is diagnosed and the patients is prescribed antibiotics. Which of the following cells will most likely be responsible for phagocytosis of the bacterial pathogens causing this patient's pneumonia? Select one: a. Lymphocytes b. Mast cells c. Polymorphonuclear cells d. Eosinophils e. Platelets

Megaloblastic Anemia Anemia - Deficiency of blood Hb due to ↓ RBC count (too rapid loss or/and too slow production) or ↓ Hb quantity in the RBC Results in ↓ oxygen-carrying capacity of the blood → hypoxia → vasodilation ↑ in pulse and respiratory rates (effort to supply sufficient oxygen to tissues) ↓ exercise & cold tolerancePale skin (↓ red colored HbO) ↑ fatigue and lassitude (lack of energy) ↓ blood viscosity → ↓ peripheral resistance → ↑ blood flow, venous return and CO and work load on the heart •Deficiency of vitamin B12, folic acid or IF (i.e., atrophic gastric mucosa, pernicious anemia) - megaloblastic anemia •Maturation failure •→ ↓ rate of erythroblasts proliferation •→ production of large precursor cells - megaloblasts and larger irregular oval erythrocytes - macrocytes fully saturated with Hb - macrocytic (megaloblastic) anemia •→ ↑ fragility of the plasma membrane → ↓ life span → anemia.

A 30 years old male is brought to the hospital with history of gastrectomy. His skin appears lemon-yellow.Investigations reveal hemoglobin 10 g/dl, odd shaped RBCs and Serum Vitamin B12 is low. He is likely to be suffering from: Select one: a. Microcitic anemia b. Aplastic Anemia c. Blood Loss Anemia d. Megaloblastic Anemia e. Hemolytic Anemia

c In Conn's syndrome, large amounts of aldosterone are secreted. Because aldosterone causes sodium re- tention, hypertension is a common finding in patients with this condition. However, the degree of sodium retention is modest, as is the resultant increase in ex- tracellular fluid volume. is occurs because the rise in arterial pressure offsets the sodium-retaining effects of aldosterone, limiting sodium retention and permitting daily sodium balance to be achieved.

A 30-year-old man has Conn's syndrome. Which of the following sets of physiological changes is most likely to occur in this patient compared with a healthy person? Select one: a. E b. D c. C d. B e. A

Decreased Brunner gland mucus production chronic stress leads to increase in sympathetic tone and decreased secretion of all GI substances, including mucus

A 30-year-old soldier in an active combat zone in Afghanistan comes to his doctor because of abdominal pain that is relieved by eating but then gets worse 2-3 hours afterward. He also complains of abdominal pain at night. Endoscopy reveals the presence of multiple duodenal ulcers. Which of the following changes may have increased this patient's risk for developing duodenal ulcers? Select one: a. Decreased pancreatic bicarbonate secretion b. Increased gastric acid secretion c. Increased gastrin levels d. Increased pepsinogen secretion e. Decreased Brunner gland mucus production

Increased insulin secretion Steroids with potent glucocorticoid activity tend to increase plasma glucose concentration. As a result, insulin secretion is stimulated. Increased glucocorti- coid activity also diminishes muscle protein. Because of feedback, cortisone administration leads to a de- crease in adrenocorticotropic hormone secretion and, therefore, a decrease in plasma cortisol concentration.

A 30-year-old woman is administered cortisone for the treatment of an autoimmune disease. Which of the following is most likely to occur? Select one: a. Increased insulin secretion b. Increased cortisol secretion c. Increased muscle mass d. Hypoglycemia between meals e. Increased adrenocorticotropic hormone secretion

150 mg/min The filtered load of glucose in this example is determined as follows: GFR (150 ml/min) x plasma glucose (300 mg/dL) = 450 mg/min. the transport maximum for glucose in this example is 300 mg/min. erefore, the maximum rate of glucose reabsorption is 300 mg/min. e urinary glucose excretion is equal to the filtered load (450 mg/min) minus the tubular reabsorption of glucose (300 mg/min), or 150 mg/min.

A 32-year-old man complains of frequent urination. He is overweight (280 lb, 5 ft 10 in tall), and after measuring the 24-hr creatinine clearance, you estimate his GFR to be 150 ml/min. His plasma glucose is 300 mg/dL. Assuming that his renal transport maximum for glucose is normal, as shown in the figure above, what would be this patient's approximate rate of urinary glucose excretion? Select one: a. 300 mg/min b. 225 mg/min c. 100 mg/min d. 0 mg/min e. 150 mg/min

Alkalinization of the antrum Alkalinization of the antrum releases the gastrin-containing cells from the inhibitory influ- ences of somatostatin and increases acid secretion. Acidification of the antrum promotes the release of somatostatin from D cells in the gastroin- testinal mucosa, which inhibits gastrin release and gastric acid secretion. Acidification of the duodenum elicits inhibitory neural and hormonal reflexes that also inhibit acid output. Administration of a histamine antag- onist reduces acid secretion by decreasing the stimulatory effect of histamine.

A 35-year-old male smoker presents with burning epigastric pain that is most pronounced on an empty stomach. A paroxysmal rise in serum gastrin in response to intravenous secretin further supports a diagnosis of Zollinger-Ellison syndrome. Normally, basal acid output is increased by which of the following? Select one: a. Administration of an H2-receptor antagonist b. Vagotomy c. Acidification of the antrum d. Alkalinization of the antrum e. Acidification of the duodenum

Atrial septal defect This patient presents with a stroke in the left parietal lobe and widely patent carotid arteries. Auscultation reveals a midsystolic murmur with a widely-split and fixed S2.. He most likely has an atrial septal defect (ASD). This pathology allowed a paradoxical embolus from the right side of the heart to pass into the left side, and then embolize in the left middle cerebral artery. The embolus is only able to pass from right to left atria when there is a transient reversal of the left to right flow that normally occurs with an ASD. This transient reversal occurs during coughs, bearing down for bowel movements, or anything that replicates the Valsalva maneuver. In normal physiology, inspiration leads to increased blood in the right ventricle, causing delay in the closure of the pulmonic valve. Expiration decreases blood in the right ventricle, leading to earlier closure of the pulmonic valve. However, with an ASD, a certain amount of blood passes from the left atrium to the right atrium on every beat. This decreases the variation in pulmonary vasculature on respiration, causing a wide and "fixed" S2 heard on auscultation.Aortic valve vegetation occurs in the setting of infection of the aortic valve. Atrial fibrillation could cause a left atrial thrombus. Patent ductus arteriosus is characterized by a machine-like continuous murmur. Pulmonary stenosis produces a systolic ejection murmur at the left second intercostal space, but does not present with fixed-splitting. A ventricular septal defect is often symptomatic from a young age; this patient has no history of heart malformations of any kind.

A 35-year-old man comes the emergency department with a 1-hour history of difficulty speaking and weakness in his right arm. MRI of the head and neck confirms a stroke in the left parietal lobe and widely patent carotid arteries. There is no history or ECG changes suggestive of atrial fibrillation. His wife, who brought him to the hospital, reports that he returned this morning from a business trip in Europe. When she picked him up from the airport, he was completely fine. Auscultation of the chest reveals the a midsystolic murmur with a widely-split and fixed S2Which of the following best accounts for this patient's stroke? Select one: a. Pulmonary stenosis b. Patent ductus arteriosus c. Ventricular septal defect d. Atrial septal defect e. Aortic valve vegetation f. Left atrial thrombus

E Pulse pressure is the difference between systolic pressure and diastolic pressure. e two major factors that affect pulse pressure are the stroke volume output of the heart and the compliance of the arterial tree. An increase in stroke volume increases systolic and pulse pressure, while an increase in compliance of the arterial tree decreases pulse pressure. Moderate aortic valve stenosis results in a decrease in stroke volume, which leads to a decrease in systolic pressure and pulse pressure.

A 35-year-old woman visits her family practice physician for an examination. She has a mean arterial blood pressure of 105 mm Hg and a heart rate of 74 beats/ min. Further tests by a cardiologist reveal that the patient has moderate aortic valve stenosis. Which of the following sets of changes would be expected in this patient? Select one: a. D b. A c. E d. C e. F f. G g. B h. H

A The difference between systolic pressure and diastolic pressure is the pulse pressure. e two major factors that affect pulse pressure are the stroke volume output of the heart and the compliance of the arterial tree. In patients with moderate aortic regurgitation (due to incomplete closure of aortic valve), the blood that is pumped into the aorta immediately flows back into the left ventricle. e backflow of blood into the left ventricle increases stroke volume and systolic pressure. e rapid backflow of blood also results in a decrease in diastolic pressure. us, patients with moderate aortic regurgitation have high systolic pressure, low diastolic pressure, and high pulse pressure.

A 35-year-old woman visits her family practitioner for an examination. She has a blood pressure of 160/75 mm Hg and a heart rate of 74 beats/min. Further tests by a cardiologist reveal that the patient has moderate aortic regurgitation. Which of the following sets of changes would be expected in this patient? Select one: a. D b. A c. B d. G e. E f. F g. C h. H

Colon Loss of gastric juice results in hypokalemic, metabolic alkalosis. Excessive loss of fluid from the gastrointestinal tract can lead to dehydra- tion and, depending on the origin of the fluid loss, electrolyte and acid- base disturbances. The hydrogen ion and potassium ion concentration of gastric juice exceeds that of the plasma. As a result, excess fluid loss leads to metabolic alkalosis accompanied by hypokalemia. Because the pancreas, liver, ileum, and colon secrete bicarbonate, excessive loss leads to meta- bolic acidosis. In addition, the colon secretes potassium. Thus, the acidosis is accompanied by hypokalemia.

A 37-year-old male presents with dehydration and hypokalemic metabolic acidosis. This acid-base and electrolyte disorder can occur with excess fluid loss from which of the following organs? Select one: a. Pancreas b. Colon c. Stomach d. Liver e. Ileum

Pancreatic enzyme secretion Inflammation or removal of the upper small intestine leads to a decrease in pancreatic and hepatobiliary function. The proximal small intestine contains a number of "receptors" that monitor the physical (volume) and chemical (pH, fat con- tent, caloric density, osmolality) composition of the chyme emptied from the stomach. Stimulation of these receptors releases secretin, which acts on pancreatic ductal cells to increase HCO3- secretion, as well as cholecys- tokinin, which acts on pancreatic acinar cells to increase pancreatic enzyme secretion (lipases, amylases, and proteases). Stimulation of proximal small intestine receptors also activates neural reflexes, which initiate pancreatic enzyme and bicarbonate secretion, stimulate gallbladder emptying, and provide feedback for inhibitory regulation of gastric function (enterogas- trone, enterogastric reflex). Removal of these reflexes decreases pancreatic secretion and gallbladder emptying and increases gastric emptying and acid output.

A 37-year-old male with AIDS presents with a fever, anorexia, weight loss, and GI bleeding. Physical examination reveals a palpable abdominal mass. Endoscopy and biopsy reveal a small-bowel malignancy, indicating surgical resection. Removal of proximal segments of the small intestine would most likely result in a decrease in which of the following? Select one: a. Gastric emptying of liquids b. Gastric emptying of solids c. Basal acid output d. Pancreatic enzyme secretion e. Maximal acid output

infusion of isotonic NaCl .9%

osmolarity stays the same, ecf volume expands

inhibits prolactin release from the anterior pituitary Bromocriptine is a dopamine agonist. The secretion of prolactin by the anterior pituitary is tonically inhibited by the secretion of dopamine from the hypothalamus. Thus, a dopamine agonist acts just like dopamine—it inhibits prolactin secretion from the anterior pituitary.

A 38-year-old man who has galactorrhea is found to have a prolactinoma. His physician treats him with bromocriptine, which eliminates the galactorrhea. The basis for the therapeutic action of bromocriptine is that it Select one: a. enhances the action of prolactin on the breast b. inhibits prolactin release from the hypothalamus c. antagonizes the action of prolactin on the breast d. inhibits prolactin release from the anterior pituitary e. enhances the action of dopamine on the anterior pituitary

Parathyroid hormone Between 85 and 90% of the filtered phosphate is reabsorbed in the proxi- mal tubule by a sodium-dependent secondary active transport system. The transporter is electrically neutral, requiring two Na+ molecules for every HPO42− molecule that it transports. The transporter is inhibited by parathy- roid hormone (PTH). The decreased reabsorption of phosphate results in an increased clearance from the plasma. PTH is released from the parathy- roid gland in response to lowered plasma Ca2+ concentrations. In addition to inhibiting the reabsorption of phosphate from the proximal tubule, PTH increases the reabsorption of Ca2+ from the loop of Henle.

A 39-year-old man presents with severe writhing back pain, hematuria, and nausea. An intravenous pyelogram (IVP) confirms a diagnosis of renal calculi. The presence of strongly opaque stones on the plain film issuggestive of calcium oxalate stones, which have an increased incidence with hypophosphatemia. The renal clearance of phosphate is increased by which of the following hormones? Select one: a. Vasopressin b. Norepinephrine c. Aldosterone d. Angiotensin e. Parathyroid hormone

Aortic valve regurgitation the blowing murmurs of relatively high pitch are usually the murmurs associated with valvular insufficiency.the key pieces of data to identify this murmur are the systolic and diastolic pressures. Aortic valve regurgitation typically has a high pulse pressure, which is the systolic - the diastolic pressure, and in this case is 100 mm Hg. Also note that the diastolic pressure decreases to very low values of 40 mm Hg as the blood leaks back into the left ventricle.

A 40-year-old woman has been diagnosed with a heart murmur. A "blowing" murmur of relatively high pitch is heard maximally over the left ventricle. " e chest x-ray shows an enlarged heart. Arterial pressure in the aorta is 140/40 mm Hg. What is the diagnosis? Select one: a. Aortic valve stenosis b. Tricuspid valve regurgitation c. Aortic valve regurgitation d. Mitral valve stenosis e. Pulmonary valve stenosis

Hemolytic anemia this patient has decreased production of red blood cells as confirmed by the anemia (low number, Hb, and Hct), yet the red blood cells being produced have a normal size, MCV 90. erefore, the patient does not have spherocytosis (small red cells) or vitamin B12 deficiency (large red cells). the normal WBC count and the increased reticulocyte count suggest that the bone marrow is functioning. the increased reticu- locyte count means that a large number of red cells are being produced. ese laboratory values support an anemia due to some type of blood loss; in this case an anemia due to hemolysis.

A 40-year-old woman visits the clinic complaining of fatigue. She had recently been treated for an infection. Her laboratory values are RBC 1.8 x 106 /ml, Hb 5.2 g/dL, hematocrit (Hct) 15, WBC 7.6 x 103 /l, platelet count 320,000/ml, mean corpuscular volume (MCV) 92 fL, and reticulocyte count 24%. What is the most likely explanationfor this presentation? Select one: a. B12 deficiency b. Aplastic anemia c. Hereditary spherocytosis d. Hemolytic anemia

Increased maximal acid output Inflammation of the proxi- mal small intestine results in a decrease in the feedback regulation of gastric function by reducing the input of the enterogastric reflex and enterogas- trone to gastric emptying and gastric acid secretion. Absent inhibitory input, basal and maximal acid output are increased, and the gastric emptying of liquids and solids is increased.

A 42-year-old airline pilot presents to his family physician with a chief complaint of midepigastric pain that is relieved by antacids or eating. Endoscopic evaluation reveals the presence of a duodenal ulcer. Based on the diagnosis, which of the following also would be expected? Select one: a. Decreased basal acid output b. Increased frequency of antral contractions c. Decreased orad stomach compliance d. Decreased gastric emptying of liquids e. Increased maximal acid output

Gastrin Zollinger-Ellison (ZE) has a triad of peptic ulcer disease, gastric acid hypersecretion, and an elevated gastrin level. In ZE, a pancreatic acinar cell adenoma (gastrinoma) is the site for the synthesis and secretion of large amounts of gastrin. Unlike gastrin released from the antrum in response to normal physiological stimuli, the pancreatic release of gastrin from the pancreas is not under physiological control, that is, intestinal feedback and gastric pH. ZE can be part of a multiple endocrine tumor (MEN I). Proton pump inhibitors (omeprazole, lansoprazole) are the treatment of choice for peptic ulcer disease in ZE, and have decreased the need for total gastrectomy.

A 42-year-old male is referred to a gastroenterologist for evaluation of refractory peptic ulcer disease. Subsequent endoscopic and laboratory data are suggestive of Zollinger-Ellison syndrome. The increased basal acid output and maximal acid output of the patient is best explained by an increase in the plasma concentration of which of the following? Select one: a. Somatostatin b. Histamine c. Secretin d. Gastrin-releasing peptide e. Gastrin

Third-degree heart block

A 55-year-old male reports several recent episodes of syncope. An electrocardiogram is performed. Which of the following arrhythmias is most commonly associated with syncope? Select one: a. First-degree heart block b. Tachycardia c. Sinus arrhythmia d. Third-degree heart block e. Second-degree heart block

Gastrin Increases in basal and maximal acid output are suggestive of inflammation or removal of the proximal small intestine. Intestinal receptors monitor the composition of chyme and elicit feedback mechanisms that regulate gastric acid secretion and gastric emptying. Absence of feedback leads to an increased presence of excitatory mediators of gastric function. Gastrin is the primary stimulus of meal- induced acid secretion by the parietal cells. Somatostatin (paracrine), secretin (endocrine), and enterogastrone (endocrine) inhibit gastric acid secretion by the parietal cells. Histamine is an excitatory paracrine media- tor of parietal cell acid secretion.

A 42-year-old salesman presents with the chief complaint of intermittent midepigastric pain that is relieved by antacids or eating. Gastric analysis reveals that basal and maximal acid output exceed normal values. The gastric acid hypersecretion can be explained by an increase in the plasma concentration of which of the following? Select one: a. Histamine b. Secretin c. Somatostatin d. Gastrin e. Enterogastrone

Decreased intestinal surface area Gluten-sensitivity enteropathy is characterized by an autoimmune-induced decrease in the absorptive surface area of the small intestine. In addition to a decrease in the area available for absorption of nutrients, minerals, electrolytes and water, the membrane transporters of the remaining villous tip cells are impaired or absent.

A 43-year-old female presents with chief complaints of bulky and frequent diarrhea and weight loss. She experiences recurrent episodes of abdominal distension terminated by passage of stools. Laboratory data reveals a microcytic anemia, decreased serum calcium, and decreased serum albumin. After additional tests she is diagnosed with glutensensitive enteropathy. Her generalized decrease in intestinal absorption can be attributed to which of the following? Select one: a. Decreased intestinal surface area b. Decreased intestinal motility c. Decreased gastric emptying d. Increased migrating motor complexes e. Increased enterohepatic circulation of bile

C About 20% of persons older than 65 years have gallstones (cholelithiasis) in the United States, and 1 million newly diagnosed cases of gallstones are reported each year. Gallstones are the most common cause of biliary obstruction. Regardless of the cause of gallstones, serum bilirubin values (especially direct or conjugated) are usually elevated. Indirect or unconjugated bilirubin values are usually normal or only slightly elevated. Only answer C shows a high level of direct bilirubin (conjugated bilirubin) compared to the level of indirect bilirubin (unconjugated bilirubin).

A 43-year-old obese woman with a history of gallstones is admitted to the emergency department because of excruciating pain in the upper right quadrant. The woman is jaundiced and x-ray suggests obstruction of the common bile duct. Which of the following values of direct and indirect bilirubin are most likely to be present in the plasma of this woman (in milligrams per deciliter)? Select one: a. C b. E c. B d. D e. A

IL-3

A 44-year-old woman is being treated for cancer and develops neutropenia. The physician is considering administration of a growth factor to stimulate leucopoiesis. First, he decides to test the level of a naturally occurring cytokine necessary to stimulate all bone marrow cell lines. Which of the following choices should he test for? Select one: a. IL-4 b. IL-5 c. IL-7 d. IL-1 e. erythropietin f. IL-6 g. IL-3 h. IL-2

Secretin ZES is typically caused by a gastrin-secreting tumor that is located in the pancreas, duodenal wall, or in lymph nodes. "e most simple and reliable test for ZES is secretin injection. Secretin inhibits antral gastrin, but it simulates gastrin secretion in patients with ZES (gastrinoma). Two units of secretin per kilogram body weight are injected intravenously. Serum gastrin levels are measured at various times for 30 min after injection. An increase in serum gastrin of more than 200 ng/mL is diagnostic for ZES. "e physiological mechanism of the secretin test remains unclear; however, it is the most important diagnostic test to exclude other conditions associated with increased acid secretion. CCK, GLIP, motilin, and pentagastrin have minimal effects on gastrin secretion and are not diagnostic for gastrinoma.

A 45-year-old man adds lots of high-fiber wheat and bran foods to his diet to reduce his cholesterol. He loses 30 lb on the new diet, but has undesirable side effects such as stomach cramps, flatulence, and diarrhea. His gastroenterologist diagnoses a syndrome called gluten-enteropathy or celiac sprue. Which of the following is decreased in this man? Select one: a. Glucose-dependent insulinotropic peptide (GLIP b. Secretin c. Motilin d. Pentagastrin e. Cholecystokinin (CCK)

Absorption of nutrients Celiac sprue is a chronic disease of the digestive tract that interferes with the absorption of nutrients from food. " e mucosal lesions seen on upper GI biopsy are the result of an abnormal, genetically determined, cell-mediated immune response to gliadin, a constituent of the gluten found in wheat. A similar response occurs to comparable proteins found in rye and barley. Gluten is not found in oats, rice, and maize. When aff ected individuals ingest gluten, the mucosa of their small intestine is damaged by an immunologically mediated inflammatory response, resulting in malabsorption and maldigestion at the brush border. Digestion of fat is normal in celiac sprue because the pancreas which secretes lipase still functions normally. Because celiac sprue causes malabsorption it should be clear that the stool content of carbohydrates, fat, and nitrogen is increased.

A 45-year-old man adds lots of high-fiber wheat and bran foods to his diet to reduce his cholesterol. He loses 30 lb on the new diet, but has undesirable side effects such as stomach cramps, flatulence, and diarrhea. His gastroenterologist diagnoses a syndrome called gluten-enteropathy or celiac sprue. Which of the following is decreased in this man? Select one: a. Stool nitrogen b. Stool carbohydrates c. Absorption of nutrients d. Digestion of fat e. Stool fat

B Alveolar air normally equilibrates with the mixed venous blood that perfuses them so that the gas com- position of alveolar air and pulmonary capillary blood are identical. When a group of alveoli are not perfused, the composition of the alveolar air becomes equal to the inspired gas composition, which has an oxygen tension of 149 mm Hg and carbon dioxide tension of about 0 mm Hg

A 45-year-old man at sea level has an inspired oxygen tension of 149 mm Hg, nitrogen tension of 563 mm Hg, and water vapor pressure of 47 mm Hg. A small tumor pushes against a pulmonary blood vessel that completely blocks the blood flow to a small group of alveoli. What are the oxygen and carbon dioxide tensions of the alveoli that are not perfused (in mm Hg)? Select one: a. A b. B c. C d. D e. E

Back-leak of hydrogen ions Hydrogen ions leak into the mucosa when it is damaged. As the hydrogen ions accumulate in the mucosa, the intracellular buff ers become saturated, and the pH of the cells decreases resulting in injury and cell death. " e hydrogen ions also damage mast cells causing them to secrete excess amounts of histamine. " e histamine exacerbates the condition by damaging blood capillaries within the mucosa. " e result is focal ischemia, hypoxia, and vascular stasis. " e mucosal lesion is a forerunner of gastric ulcer. Mucus secretion helps to strengthen the gastric mucosal barrier because mucus impedes the leakage of hydrogen ions into the mucosa. Various proton pump inhibitors are used as a treatment modality for gastric ulcer because these can decrease the secretion of hydrogen ions (protons). " e tight junctions between cells within the mucosa help to prevent the back-leak of hydrogen ions. Vagotomy was once used to treat gastric ulcer disease because severing or crushing the vagus nerve decreases gastric acid secretion.

A 45-year-old man presents with abdominal pain and hematemesis. An abdominal exam was relatively benign, and abdominal x-rays were suggestive of a perforated viscus. Endoscopy revealed a chronically perforated gastric ulcer, through which the liver was visible. Which of the following is a forerunner to gastric ulcer formation? Select one: a. Proton pump inhibition b. Mucus secretion c. Tight junctions between cells d. Vagotomy e. Back-leak of hydrogen ions

End-stage renal disease this patient is anemic, but the RBCs being pro- duced are normal (note normal MCV). e overall production of the RBCs is decreased (reticulocyte count is low). WBCs and platelets are normal, suggest- ing a normal bone marrow. Folic acid and iron deficiency anemia would result in a lower RBC MCV. Hemolytic anemia would result in an increase reticulocyte count. e elevated blood pressure provides evidence of renal disease. is patient has end-stage renal disease and decreased erythropoietin production.

A 45-year-old woman developed fatigue in July and had blood counts that were reported to be normal. She washospitalized because of a very severe headache in December, and was found to have a blood pressure of 175/90. Her laboratory values were as follows: hemoglobin (8.3 g/dL), RBC count (2.2 x 106 /ml), Hct (23%), MCV (89 fL), WBCs (5100/! l), platelets (262 x 103 /ml), and reticulocyte count 0.8%. What is the diagnosis for this patient? Select one: a. Iron deficiency b. End-stage renal disease c. Folic acid deficiency d. Hemolytic anemia

Hypothyroidism due to an abnormality in the hypothalamus Lethargy and myxedema are signs of hypothy- roidism. Low plasma levels of thyroid-stimulating hormone indicate that the abnormality is in either the hypothalamus or the pituitary gland. Because the pituitary was responsive to the administration of thyrotropin-releasing hormone (TRH), this suggests that pituitary function is normal and that the hypo- thalamus is producing insufficient amounts of TRH.

A 46-year-old man has "puffy" skin and is lethargic. His plasma thyroid-stimulating hormone concentration is low and increases markedly when he is given thyrotropin-releasing hormone. Which of the following is the most likely diagnosis? Select one: a. Hyperthyroidism due to a thyroid tumor b. Hypothyroidism due to an abnormality in the thyroid c. Hypothyroidism due to an abnormality in the hypothalamus d. Hyperthyroidism due to an abnormality in the hypothalamus e. Hypothyroidism due to an abnormality in the pituitary

A higher-than-normal flow of hypotonic urine The presence of a mass in the posterior pituitary, coupled with the presen- tation of thirst and nocturia, suggest that the patient has a central diabetes insipidus with inadequate pituitary secretion of antidiuretic hormone (ADH). As a result of decreased ADH, the urine will have a low tonicity. On MRI, the absence of the normal bright spot in the region of the posterior pituitary further supports the diagnosis.

A 46-year-old man presents to his physician with a 12-week history of frontal headaches. A computed tomography (CT) of the brain shows a mass in the posterior pituitary, and the posterior pituitary "bright spot" is absent on MRI. The patient also complains of increased thirst and waking up frequently during the night. Which of the following best describes his urine? Select one: a. A normal flow of hypertonic urine b. A higher-than-normal flow of hypotonic urine c. A lower-than-normal flow of hypotonic urine d. A higher-than-normal flow of hypertonic urine e. A lower-than-normal flow of hypertonic urine

primary overproduction of ACTH (Cushing's disease) This woman has the classic symptoms of a primary elevation of adrenocorticotropic hormone (ACTH) [Cushing's disease]. Elevation of ACTH stimulates overproduction of glucocorticoids and androgens. Treatment with pharmacologic doses of glucocorticoids would produce similar symptoms, except that circulating levels of ACTH would be low because of negative feedback suppression at both the hypothalamic [corticotropin-releasing hormone (CRH)] and anterior pituitary (ACTH) levels. Addison's disease is caused by primary adrenocortical insufficiency. Although a patient with Addison's disease would have increased levels of ACTH (because of the loss of negative feedback inhibition), the symptoms would be of glucocorticoid deficit, not excess. Hypophysectomy would remove the source of ACTH. A pheochromocytoma is a tumor of the adrenal medulla that secretes catecholamines.

A 46-year-old woman has hirsutism, hyperglycemia, obesity, muscle wasting, and increased circulating levels of adrenocorticotropic hormone (ACTH). The most likely cause of her symptoms is Select one: a. treatment with exogenous glucocorticoids b. hypophysectomy c. pheochromocytoma d. primary overproduction of ACTH (Cushing's disease) e. primary adrenocortical insufficiency (Addison's disease)

A decreased pulse pressure In aortic stenosis, the resistance of the aortic valve increases, making it more difficult for blood to be ejected from the heart. Because a pressure drop occurs across the stenotic aortic valve, the ventricular pressure is much larger than the aortic pressure. Although stroke volume typically decreases leading to a decrease in pulse pressure, a normal cardiac output and arter- ial pressure can still be maintained by increasing heart rate. However, the increased afterload will lead to a decreased ejection fraction and increased cardiac oxygen consumption.

A 47-year-old female is brought to the Emergency Department because she fainted at the gym during her daily aerobic workout. A prominent systolic murmur is heard and a presumptive diagnosis of aortic stenosis is made. Which of the following is consistent with that diagnosis? Select one: a. A decreased left ventricular diastolic pressure b. An increased ejection fraction c. A decreased cardiac oxygen consumption d. An increased arterial pressure e. A decreased pulse pressure

Iron is transported in the blood bound to transferrin Iron is transported in the blood bound to the b globulin, transferrin. Excess iron is stored in all cells, but especially in hepatocytes where it combines with apoferritin. The stored form is called ferritin. The rate of iron absorption is extremely slow, with a maximum of only a few milligrams per day. Iron is absorbed pri- marily in the ferrous form. Therefore, ferrous iron compounds, rather than ferric compounds, are effective in treating iron deficiency.

A 47-year-old woman with hypermenorrhea develops an iron-deficiency anemia requiring iron supplements. Which of the following statements is correct regarding iron digestion and absorption? Select one: a. Iron is absorbed rapidly from the small intestine b. About 100 mg of iron is absorbed per day c. Iron is transported in the blood bound to transferrin d. Iron is transported into enterocytes by a ferroportin transporter on the apical membrane e. In general, iron must be oxidized from the ferrous to the ferric state for efficient absorption

Phase 0, which is primarily characterized by sodium influx

A 48-year-old female comes into the ER with chest pain. An electrocardiogram (EKG) shows a heart beat of this individual in Image A. The QR segment best correlates with what part of the action potential of the ventricular myocyte shown in Image B? Select one: a. Phase 0, which is primarily characterized by potassium efflux b. Phase 1, which is primarily characterized by potassium and chloride efflux c. Phase 1, which is primarily characterized by calcium efflux d. Phase 3, which is primarily characterized by potassium efflux e. Phase 0, which is primarily characterized by sodium influx

increased insulin resistance

A 48-year-old man comes to his physician because of a gradual onset of weakness, accompanied by what he sees as a decrease in muscle mass and an increase in abdominal obesity during the past 2 years. Although his diet and daily routine have not changed, he felt that he was "wasting away." Stimulation with growth hormone-releasing hormone-arginine yielded a subnormal rise in growth hormone levels. A diagnosis was made and the patient began treatment. After a few months, the patient's muscle mass returned to normal, and he noticed improved strength and a thinner waistline. During a routine physical and workup, the patient's fasting glucose levels are found to be elevated. However, the patient has no prior history of diabetes. Which of the following is the most likely cause of this patient's abnormal fasting glucose level? Select one: a. Increased 1,25-dihydroxycholecalciferol level b. Loss of GLUT4 receptors c. Decreased insulin level d. Increased somatostatin level e. Increased insulin resistance

D Vitamin B12 is absorbed primarily by the ileum.

A 48-year-old man consumes a healthy meal. At which of the following locations is vitamin B12 most likely to be absorbed? Select one: a. D b. B c. A d. E e. C

1/16

A 48-year-old man presents to the emergency department with chest pain that radiates to his jaw and left shoulder. Angina pectoris is suspected, and he is sent for an angiogram. The test reveals an atherosclerotic coronary artery that is 50% occluded. The maximal blood flow through this artery is reduced by Select one: a. 1/16 b. 1/2 c. 1/8 d. 1/32 e. 1/4

A The frequency of slow waves is fixed in various parts of the gut. "e maximum frequency of smooth muscle contractions cannot exceed the slow wave frequency. The slow wave frequency averages about 3 per minute in the stomach, 12 per minute in the duodenum, 10 per minute in the jejunum, and 8 per minute in the ileum. Therefore, the duodenum is most likely to have the highest frequency of smooth muscle contractions

A 48-year-old woman consumes a healthy meal. At which location are smooth muscle contractions most likely to have the highest frequency in the diagrams shown? Select one: a. B b. C c. A d. E e. D

Orad stomach accommodation Orad stomach accommodation depends exclusively on an intact vagovagal reflex. Vagal innervation of the gastrointestinal tract extends from the esophagus to the level of the transverse colon. Preganglionic fibers from cell bodies in the medulla synapse with ganglion cells located in the enteric nervous system. Distention-induced contraction of gastrointestinal smooth muscle devel- ops as the result of long (vago-vagal) and local (enteric nerves) reflexes. The importance of long versus local reflex pathways varies along the gut. Secondary esophageal peristalsis, intestinal segmentation, and migrating motor complexes are unaffected by vagotomy, whereas caudad stomach peristalsis is decreased but not abolished by vagotomy.

A 49-year-old man undergoes vagotomy for his peptic ulcer disease. As a result, which of the following gastrointestinal motor activities will be affected most? Select one: a. Distention-induced intestinal segmentation b. Secondary esophageal peristalsis c. Migrating motor complexes d. Caudad stomach peristalsis e. Orad stomach accommodation

Abnormal sweat chloride test An abnormal sweat chloride test is an expected diagnostic feature of cystic fibrosis. The chloride channel is thought to be regulated by the cystic fibrosis transmembrane regulator (CFTR) protein, which is defective in cystic fibrosis. A low C3 complement level (choice B) may cause severe infections. The nitroblue tetrazolium (NBT) dye test (choice C) is an in vitro test for a respiratory burst in neutrophils. Allergic type I hypersensitivity (choice D) conditions are characterized by an increase immunoglobulin E antibodies associated with bronchial asthma. The finding of gram-positive diplococci in the sputum (choice E) is associated with Streptococcus pneumoniae infection.

A 5-year-old boy has a history of growth retardation; pulmonary infections; and bulky, oily, malodorous stools.Which of the following test results would be expected in this patient? Select one: a. Abnormal sweat chloride test b. Abnormal nitroblue tetrazolium (NBT) dye test c. Positive wheel and flare reaction with antigen scratch testing d. Sputum with gram-positive diplococci e. Low C3 complement level

Decreased secretion of antidiuretic hormone from the pituitary gland An inappropriately high rate of antidiuretic hor- mone (ADH) secretion from the lung promotes excess water reabsorption, which tends to produce concen- trated urine and a decrease in plasma osmolality. Low plasma osmolality suppresses both thirst and ADH secretion from the pituitary gland

A 55-year-old man has developed the syndrome of inappropriate antidiuretic hormone secretion due to carcinoma of the lung. Which of the following physiological responses would be expected? Select one: a. Inappropriately low urine osmolality (relative to plasma osmolality) b. Increased plasma osmolality c. Decreased secretion of antidiuretic hormone from the pituitary gland d. Increased thirst

Decreasing the interval between contractions When the interval between skeletal muscle contractions is small, the force produced by the two successive contractions will summate. The shorter the interval between the contractions, the greater the summation will be. Maximum summation is called tetanus. Decreasing extracellular Ca2+ will increase the excitability of skeletal muscle fibers but does not have a direct effect on contractile force. Increasing the Mg2+ concentration will decrease skeletal muscle excitability. Increasing the preload beyond 2.2 mm decreases the overlap between thick and thin filaments and therefore decreases the force of contraction. Increasing the activity of acetylcholine esterase enhances the hydrolysis of ACh and therefore decreases the likelihood that muscle contraction will be initiated.

A 5-year-old boy presents with abnormal running, jumping, and hopping. His parents have observed that he uses his arms to climb up his legs when rising from the floor. The pediatrician suspects Duchenne muscular dystrophy, and electromyography confirms a myopathy. The amount of force produced by a skeletal muscle can be increased by which of the following? Select one: a. Decreasing extracellular Ca2+ b. Increasing the activity of acetylcholine esterase c. Increasing the preload beyond 2.2 mm d. Increasing extracellular Mg2+ e. Decreasing the interval between contractions

Aortic valve stenosis this patient has a QRS axis of -45°, indicating a leftward axis shift. In other words, the left side of the heart is enlarged. In aortic valve stenosis the left side of the heart is enlarged because of the extra tension the left ventricular walls must exert to expel blood out the aorta. "erefore, these symptoms fit with a patient with aortic stenosis. In pulmonary valve stenosis, the right side of the heart hypertrophies, and in mitral valve stenosis there is no left ventricular hypertrophy. In tricuspid valve regurgitation the right side of the heart enlarges, and in tricuspid valve stenosis no ventricular hypertrophy occurs.

A 50-year-old female patient at UMC has been diagnosed with a heart murmur. A murmur of relatively low pitch is heard maximally over the second intercostal space to the right of the sternum. The chest x-ray shows an enlarged heart. " e mean QRS axis of the EKG is -45°. The diagnosis is Select one: a. Mitral valve stenosis b. Tricuspid valve regurgitation c. Tricuspid valve stenosis d. Aortic valve stenosis e. Pulmonary valve stenosis

E

A 50-year-old male patient with liver cancer is in advanced-stage hepatic failure. What effect will this have on his capillary colloid osmotic pressure, his interstitial hydrostatic pressure, and the net filtration in his systemic capillaries? Select one: a. A b. B c. C d. D e. E f. F

point U

A 50-year-old man visits his physician for an annual exam. He complains of mild breathlessness on exertion. Upon cardiac auscultation the physician detects an S3 heart sound. At which point on the cardiac cyclediagram does the S3 heart sound occur? Select one: a. R b. U c. P d. T e. Q f. S

Myogenic properties of LES smooth muscle The lower esophageal sphincter is a high-pressure zone that exists between the esophageal body and the gastric fundus. The high pressure limits reflux of gastric contents into the esophageal body. Although excitatory vagal input contributes to the high-pressure zone, the principal determinant is intrinsic (myogenic) properties of the circular smooth muscle of the sphincter. Excess acid in the esophagus creates the pain sensation referred to as heartburn.

A 53-year-old male complains of a mild chronic cough and heartburn. Esophageal manometric and endoscopic evaluation reveal a hypotensive lower esophageal sphincter (LES) pressure and mild gastroesophageal reflux. Which of the following is the primary genesis of LES pressure in adults? Select one: a. Circulating gastrin b. Tonic excitatory parasympathetic nerve input to the smooth muscle c. Local production of nitric oxide by enteric nerves d. Myogenic properties of LES smooth muscle e. Tonic excitatory sympathetic nerve input to the smooth muscle

Increased serum gastrin Secretin inhibits gastrin release from the antrum of the stomach, but it stimulates gastrin secretion from a gastrinoma. "us, patients with a gastrinoma have increased serum gastrin levels within 30 min after secretin administration; whereas secretin decreases serum gastrin levels in normal subjects. Secretin injection is the most simple and reliable test for gastrinoma; however, the physiological mechanism of the secretin test is poorly understood. Secretin normally inhibits gastric acid secretion, but it could conceivably increase acid secretion in patients with gastrinoma because of the increase in gastrin secretion that occurs. Secretin can inhibit gastric emptying when pharmacological doses are given, but this is not diagnostic for gastrinoma. Secretin has a normal physiological effect to stimulate pancreatic HCO3" secretion, which is independent of gastrinoma.

A 53-year-old man with a recurrent history of ulcer disease associated with diarrhea and a strong family history of duodenal ulcer disease is suspected of having Zollinger-Ellison syndrome (gastrinoma). Secretin (2 units/kg) was given as a rapid intravenous injection to test for gastrinoma. Which of the following results would support the existence of gastrinoma following secretin administration? Select one: a. Inhibition of gastric emptying b. Decreased serum gastrin c. Inhibition of gastric acid secretion d. Increased serum gastrin e. Stimulation of pancreatic HCO3- secretion

Anemia The third heart sound (S3) is associated with rapid ventricular filling of the left ventricle. S3 is commonly heard in children and young adults and is also heard in conditions when rapid filling of the ventricle is abnormally high, for example, in anemia or mitral regurgitation. It can also occur in dilated car- diomyopathy, restrictive cardiomyopathy, or cardiac tamponade when the compliance of the left ventricle is reduced. An increased heart rate reduces the duration of diastole, and thus tends to decrease ventricular filling.

A 55-year-old female presents for her annual physical examination. Upon auscultation, a third heart sound is heard. The differential diagnosis of this finding includes which of the following? Select one: a. Aortic regurgitation b. Anemia c. Mitral stenosis d. Tachycardia e. Right bundle branch block

300 mg/min The kidneys excrete little or no glucose as long as the filtered load of glucose (the product of the GFR and the plasma glucose concentration) does not exceed the tubular transport maximum for glucose. Once the filtered load of glucose rises above the transport maximum, the excess glucose filtered is not reabsorbed and passes into the urine. erefore, the urinary excretion rate of glucose can be calculated as the filtered load of glucose minus the transport maximum. In this example, the filtered load of glu- cose is the GFR (150 ml/ min) multiplied by the plasma glucose concentration (400 mg/100 ml, or 4 mg/ml) which is equal to 600 mg/min. Since the transport maximum is only 300 mg/min, the rate of glucose excretion would be 600 minus 300 mg/min, or 300 mg/min.

A 55-year-old overweight male patient complains of frequent urination and his blood pressure is 165/98 mm Hg. Based on 24-hour creatinine clearance, you estimate his GFR to be 150 ml/min. His plasma glucose is 400 mg/100 ml. Assuming that his renal transport maximum for glucose is normal, as shown in the figure, what would be the approximate rate of urinary glucose excretion for this patient? Select one: a. 0 mg/min b. 300 mg/min c. 150 mg/min d. 225 mg/min e. 100 mg/min

Levels of ACh at the muscle end-plates Myasthenia gravis is an autoimmune disease in which antibodies damage postsynaptic nicotinic acetylcholinereceptors. This damage prevents the firing of an action potential in the postsynaptic membrane.Tensilon is a readily reversible acetylcholinesterase inhibitor that increases acetylcholine levels in the neuromuscular junction, thereby increasing the strength of muscle contraction.

A 55-year-old woman visits her physician because of double vision, eyelid droop, difficulty chewing and swallowing, and general weakness in her limbs. All these symptoms are made worse with exercise and occur more frequently late in the day. The physician suspects myasthenia gravis and orders a Tensilon test. The test is positive. The increased muscle strength observed during the Tensilon test is due to an increase in which of the following? Select one: a. Number of ACh receptors on the muscle end-plates b. Synthesis of norepinephrine c. Amount of acetylcholine (ACh) released from the motor nerves d. Levels of ACh at the muscle end-plates

Increased left atrial pressure Increased rather than decreased left atrial pressure would be seen in a patient with mitral stenosis as a result of a pressure gradient it creates between the left ventricle and the left atrium. An overall decrease in left ventricular pressure would not be seen in a patient with mitral valve stenosis. The decrease only occurs relative to the left atrium. Increased left ventricular pressure would be seen in patients with aortic stenosis. Increased right atrial pressure occurs in response to pulmonic valve stenosis or tricuspid valve stenosis.

A 56-year-old man comes to his primary care physician for a check-up for the first time in 3 years. His medical history is significant for hypercholesterolemia and type 2 diabetes mellitus, as well as for an acute illness at the age of 9 years. The childhood illness involved a high fever, pleuritic chest pain, migrating joint pain, and a pink, nonpruritic rash on his torso. His vital signs include a blood pressure of 135/85 mm Hg and heart rate of 70. Auscultation of his heart reveals a low-pitched diastolic rumble heard best at the apex. No abnormal findings are detected by echocardiography. Of the following, which is the most likely change in pressure that would be seen in this patient? Select one: a. Decreased left atrial pressure b. Decreased left ventricular pressure c. Increased right atrial pressure d. Increased left atrial pressure e. Increased left ventricular pressure

Hypersegmented Neutrophils

A 56-year-old man with a history of Crohn's Disease presents to the doctor's office for follow up after a recent surgery removing a portion of his terminal ileum. The patient complains of mild symptoms of weakness and parasthesias. The physician decides to perform a blood smear. Which of the following changes is expected to be seen on the smear that would be consistent with the patient's symptoms? Select one: a. Normocytic anemia b. Microcytic anemia c. Hypersegmented Neutrophils d. Thrombocytopenia e. Hypochromasia

Na+ channels are closed by depolarization Elevated serum K+ concentration causes depolarization of the K+ equilibrium potential, and therefore depolarization of the resting membrane potential in skeletal muscle. Sustained depolarization closes the inactivation gates on Na+ channels and prevents the occurrence of action potentials in the muscle.

A 56-year-old woman with severe muscle weakness is hospitalized. The only abnormality in her laboratory values is an elevated serum K+ concentration. The elevated serum K+ causes muscle weakness because Select one: a. Na+ channels are opened by depolarization b. K+ channels are opened by depolarization c. the Na+ equilibrium potential is hyperpolarized d. the resting membrane potential is hyperpolarized e. Na+ channels are closed by depolarization f. K+ channels are closed by depolarization g. the K+ equilibrium potential is hyperpolarized

Increased water content of the feces Removal of the terminal ileum can lead to diarrhea and steatorrhea. The terminal ileum contains specialized cells responsible for the absorption of primary and secondary bile salts by active transport. Bile salts are necessary for adequate digestion and absorption of fat. In the absence of the terminal ileum there will be an increase in the amounts of bile acids and fatty acids delivered to the colon. Fats and bile salts in the colon increase the water content of the feces by promoting the influx (secretion) of water into the lumen of the colon.

A 57-year-old female undergoes resection of the terminal ileum as part of treatment for her chronic inflammatory bowel disease. Removal of the terminal ileum will most likely result in which of the following? Select one: a. Decreased glucose absorption b. Increased bile acid concentration in the enterohepatic circulation c. Increased water content of the feces d. Decreased fat absorption e. Increased fat absorption

An increased left atrial pressure Atrial fibrillation is an arrhythmia in which the electrical activity of the atrium becomes disorga- nized and therefore unable to produce a coordinated atrial contraction. The absence of an atrial pulse reduces the emptying of the atria during diastole and results in an enlarged left atrium and increased left atrial pressure. The venous A wave represents atrial contraction and disappears due to the absence of an atrial beat. Decreased filling of the heart results in a decrease in stroke volume. Heart rate increases because the continuous electrical activity of the atria ini- tiates a high rate of ventricular activity. Systemic blood pressure typically falls because of inadequate filling of the ventricles and the resulting decrease in stroke volume.

A 57-year-old male complains of an irregular heart beat that he notices is relieved by pressing on his eyeball. An electrocardiogram reveals atrial fibrillation. Which of the following is most likely to accompany this condition? Select one: a. An increased mean arterial blood pressure b. An increased venous A wave c. An increased left atrial pressure d. An increased stroke volume e. A decreased heart rate

Bile salts The terminal ileum contains specialized cells responsible for the absorption of primary and secondary bile salts by active transport. Bile salts are necessary for adequate digestion and absorption of fat. Resection of the ileum prevents the absorp- tion of bile acids, which leads to steatorhea. In addition, diarrhea results because the unabsorbed bile acids enter the colon where they increase adenylate cyclase activity, thus promoting the secretion of water into the lumen of the colon causing an increase in the water content of the feces. Distal small bowel resection causes a greater degree of malabsorption than removal of the same length of proximal bowel.

A 57-year-old man undergoes resection of the distal 100 cm of the terminal ileum as part of treatment for Crohn's disease. The patient likely will develop malabsorption of which of the following? Select one: a. Protein b. Bile salts c. Lactose d. Iron e. Folate

B Point A corresponds to the opening of the mitral valve at the beginning of diastole the line from A to C shows the increase in ventricular volume during diastole Point C marks the beginning of systole as left ventricular pressure becomes greater than left atrial pressure, causing the mitral valve to close. This closure (in conjunction with the closure of the tricuspid valve) represents S1. The line from point C to D corresponds to isovolumetric contraction, during which both the mitral and aortic valves remain closed as the left ventricular pressure increases. At point D the left ventricular pressure becomes greater than the aortic pressure and the aortic valve opens. Between points D and F, the left ventricular pressure continues to increase as the ventricle continues to contract and blood is ejected from the left ventricle into the aorta. At point F the aortic valve closes when the left ventricle begins to relax and the left ventricular pressure becomes less than aortic pressure. This closure (in conjunction with the closure of the pulmonic valve) represents S2. The line from point F to point A represents the isovolumetric relaxation that occurs after the end of ventricular systole. When the left ventricular pressure becomes less than the pressure in the left atrium, the mitral valve opens, thus beginning a new loop of the cardiac cycle (diastole plus systole). Point B corresponds to the point near the end of diastole when S4 may be heard. An S4 (which occurs when a stiff ventricle causes turbulent flow in the atria), commonly follows the "atrial kick" (forceful atrial systole, a cause of the S4). It is not normally present in adults. Its presence suggests a decrease in ventricular compliance, such as occurs in ventricular hypertrophy resulting from chronic hypertension. S4 is thought to result from vibration of a stiff, noncompliant ventricular wall as blood is rapidly ejected into the ventricle.

A 58-year-old man with a past medical history of hypertension goes to his physician for a routine visit. On physical examination the physician is able to detect an S4 heart sound, and refers the patient to a cardiologist. After a thorough work-up, he is found to have left ventricular hypertrophy. The image below plots left ventricular pressure versus left ventricular volume for a single cardiac cycle.This patient's S4 heart sound heard on auscultation would best correspond to which of the following points? Select one: a. A b. F c. D d. C e. B f. E

Enterochromaffin-like cells

A 59-year-old male comes to his doctor because he is concerned about his health. He says that he has unintentionally lost about 15 pounds in the last few months, feels like he is more tired and pale, and also is concerned that his tongue has become unusually red. A peripheral blood smear shows a macrocytic anemia. Methylmalonic acid and homocysteine levels are elevated, and evaluation of stomach secretions shows a lack of intrinsic factor. Endoscopy shows atrophy of the stomach, but a biopsy would show increased levels of which of the following cells? Select one: a. I cells b. Chief cells c. G cells d. Surface foveolar cells e. Enterochromaffin-like cells

Mobitz type II heart block

A 59-year-old man presents to emergency department after two episodes of loss of consciousness without an apparent cause. His wife, who witnessed the episodes, states that before each episode, he became slightly pale, suddenly fell to the ground, and remained unresponsive for about one minute. He did not move or shake, and his breathing continued normally. The patient has a history of hypertension, coronary artery disease, and an anterior myocardial infarction six months ago that required a stent placement. He takes hydrochlorothiazide, lisinopril, metoprolol, and aspirin. He has no family history of neurologic or cardiovascular diseases. The medical workup includes basic laboratory testing and an electrocardiogram, which is shown Which of the following conditions is represented by the electrocardiogram? Select one: a. Sinus bradycardia b. Mobitz type I heart block c. First degree heart block d. Mobitz type II heart block e. Third degree heart block

Factor VIII Hemophilias are hereditary bleeding disorders caused by lack of clotting factorsHemophilia A - most common type (83% of all cases) due to a deficiency of factor VIIIHemophilia B - results from a deficiency of factor IXHemophilia C - mild type, caused by a deficiency of factor XISymptoms include prolonged bleeding and painful and disabled jointsHemophilia A and B are sex linked (X chromosome)Usually occurs in males Females are hemophilia carriers. Only under rare circumstances females actually suffer from hemophilia

A 6 year old boy bruises easily and has previously bleeding gums. The maternal grandfather also has a bleeding disorder. You suspect the deficiency of Select one: a. Factor X b. Factor II c. Factor VIII d. Prothrombin activator e. Factor XIII

B A person with atherosclerosis would be expected to have decreased arterial compliance. e decrease in arterial compliance would lead to an increase in sys- tolic pressure and pulse pressure.

A 60-year-old man visits his family practitioner for an annual examination. He has a mean blood pressure of 130 mm Hg and a heart rate of 78 beats/min. His plasma cholesterol level is in the upper 25th percentile, and he is diagnosed as having atherosclerosis. Which of the following sets of changes would be expected in this patient? Select one: a. H b. A c. B d. E e. F f. C g. D h. G

Third-degree A-V heart block By definition, first-degree A-V heart block occurs when the P-R interval exceeds a value of 0.20 sec, but without any dropped QRS waves. In the following figure, the P-R interval is about 0.30 sec, which is con- siderably prolonged. However, there are no dropped QRS waves. During second-degree A-V block or third- degree A-V block, QRS waves are dropped.

A 60-year-old man weighing 220 lb had the following EKG, which shows the standard lead II. What is his diagnosis? Select one: a. First-degree A-V heart block b. Atrial flutter c. Second-degree A-V heart block d. A-V nodal rhythm e. Tird-degree A-V heart block

Ventricular rate of contraction is 140 beats/min Atrial fibrillation has a rapid irregular heart rate. e P waves are missing or are very weak. e atria exhibit circus movements, and often are very enlarged, causing the atrial fibrillation.

A 60-year-old woman has been diagnosed with atrial fibrillation. Which of the following statements best describe this condition? Select one: a. P waves of the EKG are pronounced b. Atria are smaller than normal c. Ventricular contractions occur at regular intervals d. Ventricular rate of contraction is 140 beats/min e. QRS waves are more pronounced than norma

Left bundle branch block The patient has a left axis deviation because of the large negative deflection of the R wave in lead III. Also, her T wave was inverted in lead I, which means that it is in the opposite direction of the QRS complex. is is characteristic of bundle branch block. Also, the QRS complex had a width of 0.20 sec, a very prolonged QRS complex. A QRS complex that has a width greater than 0.12 sec is normally caused by a conduction block. All these factors indicate that this patient has a left bundle branch block.

A 60-year-old woman has lost some ability to perform normal household tasks and is not feeling well. An EKG shows a QRS complex with a width of 0.20 sec, the T wave is inverted in lead I, and the R wave has a large negative deflection in lead III. Which of the following is the likely diagnosis? Select one: a. Right bundle branch block b. Left ventricular hypertrophy c. Pulmonary valve stenosis d. Left bundle branch block e. Right ventricular hypertrophy

Atrial fibrillation First-, second-, and third-degree heart blocks as well as atrial paroxysmal tachycardia all have P waves in the EKG. However, there are usually no evident P waves during atrial fibrillation, and the heart rate is irregular. erefore, this EKG is characteristic of atrial fibrillation.

A 60-year-old woman sees her physician for her annual physical examination. !e physician orders an EKG, which is shown below. Which of the following is the likely diagnosis? Select one: a. Second-degree A-V block b. Atrial paroxysmal tachycardia c. third-degree A-V block d. First-degree A-V block e. Atrial fibrillation

D When feces enters the rectum, distention of the rectal wall initiates signals that spread through the myenteric plexus to initiate peristaltic waves in the descending colon, sigmoid colon, and rectum all of which force feces toward the anus. At the same time the internal anal sphincter relaxes allowing the feces to pass. In people with transected spinal cords, the defecation reflexes can cause automatic emptying of the bowel because the external anal sphincter is normally controlled by the conscious brain through signals transmitted in the spinal cord.

A 60-year-old woman severs her spinal cord at T6 in an automobile accident. She devises a method to distend the rectum to initiate the rectosphincteric reflex. Rectal distension causes which of the following in this woman? Select one: a. A b. D c. B d. E e. C f. F

Pulmonary hypertension The EKG from this patient has a positive deflection in aVF and a negative deflection in standard limb lead I. erefore, the mean electrical axis is between 90° and 180°, which is a rightward shift in the EKG mean electrical axis. Systemic hypertension, aortic valve stenosis, and aortic valve regurgitation cause hypertrophy of the left ventricle and thus a leftward shift in the mean electrical axis. Pulmonary hyperten- sion causes a rightward shift in the axis, and is there- fore characterized by this EKG.

A 60-year-old woman tires easily. Her EKG shows a QRS complex that is positive in the aVF lead and negative in standard limb lead I. A likely cause of this condition is which of the following? Select one: a. Chronic systemic hypertension b. Aortic valve regurgitation c. Aortic valve stenosis d. Pulmonary hypertension

polycythemia vera the increase in RBC, WBC, and platelets suggests that the patient is suffering from polycythemia vera. Renal disease would result in a low EPO level, but the RBC count would be low. Myeloid leukemia would result in an increase in WBCs, with no increase in RBCs. Secondary polycythemia would have an elevated EPO level. Relative is due to dehydration.

A 62-year-old female arrives for her annual physical. She complains of itching in her hands along with headaches and vertigo. A routine complete blood count (CBC) shows red blood cells (RBCs) of 8.2 million/ml, white blood cells (WBCs) 37,000/ml, and platelets 640,000/ml. Her erythropoietin levels are lower than normal. the primary diagnosis would be Select one: a. secondary polycythemia b. polycythemia vera c. myeloid leukemia d. relative polycythemia e. thrombocytopenia

Asbestosis Asbestosis is a constricted lung disease character- ized by diffuse interstitial fibrosis. In constricted lung disease (more commonly called restrictive lung dis- ease), the MEFV curve begins and ends at abnormally low lung volumes, and the flow rates are often higher than normal at any given lung volume, as shown on the diagram. Lung volumes are expected to be higher than normal in asthma, bronchospasm, emphysema, old age, and other instances in which the airways are narrowed or radial traction of the airways is reduced allowing them to close more easily.

A 62-year-old man complains to his physician that he has difficulty breathing. !e following diagram shows a maximum expiratory flow-volume (MEFV) curve from the patient (green line) and from a typical healthy individual (red curve). Which of the following best explains the MEFV curve of the patient? Select one: a. Bronchospasm b. Asthma c. Asbestosis d. Emphysema e. Old age

C THe medical treatment of gastric ulcers is aimed at restoring the balance between acid secretion and mucosalprotective factors. Proton pump inhibitors are drugs that covalently bind and irreversibly inhibit the H!/K! adenosine triphosphatase (ATPase) pump, effectively inhibiting acid release. "erapy can also be directed toward histamine release, that is, H2 blockers, such as cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), and nizatidine (Axid). "ese agents selectively block the H2 receptors in the parietal cells. Antibiotic therapy is used to eradicate the H. pylori infection. NSAIDS (nonsteroidal anti-inflammatory agents) can cause damage to the gastric mucosal barrier, which is a forerunner of gastric ulcer.

A 62-year-old man with dyspepsia and a history of chronic gastric ulcer has abdominal pain. Endoscopy shows a large ulcer in the proximal gastric body. Biopsies were positive for Helicobacter pylori. Which of the following are used clinically for treatment of gastric ulcers of various etiologies? Select one: a. D b. C c. E d. A e. B

Decreased gastric emptying of solids The vagus nerve is the primary neural mediator of gastric function. Activation of distension-mediated vago-vagal reflexes in response to the presence of food in the stomach will (1) increase gastric compliance (receptive relaxation or accommodation reflex) and promote gastric retention of food, (2) increase the strength of antral peristaltic contractions necessary for trituration of solids, and (3) increase gastric acid secretion. Sectioning of the vagus nerve fibers to the antral region of the stomach will decrease the strength of contractions thereby prolonging the emptying of solids. The emptying of liquids will be unaffected.

A 63-year-old female is diagnosed with an intractable duodenal ulcer. After consultation with a surgeon, it is recommended that she undergoes a parietal cell vagotomy. Subsequently the patient experiences nausea and vomiting after ingestion of a mixed meal. Which of the following best explains her symptoms? Select one: a. Decreased gastric emptying of liquids b. Increased gastric emptying of liquids c. Increased gastric emptying of solids d. Decreased gastric emptying of solids e. Increased emptying of liquids and solids

A high velocity of blood within the carotid artery

A 63-year-old woman presented with acute onset of right eye pain. Ophthalmic and neurologic examinations were normal except for a loud right carotid bruit. The eye pain ceased following carotid endarterectomy (a surgical procedure to remove the atheromatous plaque material, or blockage, in the lining of an artery). The bruit was most likely caused by which of the following? Select one: a. Widening of the carotid artery b. An increase in blood viscosity c. A high velocity of blood within the carotid artery d. An increase in hematocrit e. Lengthening of the carotid artery

Warfarin this clot is due to stasis of blood flow in her venous circulation. Heparin is used for the prevention of a clot, but has to be infused. is anticoagulation occurs by heparin binding to antithrombin III and the subsequent inactivation of thrombin. A continuous heparin drip is impractical. Warfarin is used to inhibit the formation of vitamin K clotting factors and would prevent the formation of any clot. Aspirin is used to prevent activation of platelets. e current clot is not due to activation of platelets. Vitamin K will be used to restore clotting factors that may be decreased after warfarin treatment. is patient has sufficient clotting factors as evidenced by her venous clot.

A 63-year-old woman returned to work following a vacation in New Zealand. Several days after returning home, she awoke with swelling and pain in her right leg and her leg was blue. She went immediately to the emergency room where an examination showed an extensive deep vein thrombosis involving the femoral and iliac veins on the right side. Following resolution of the clot, this patient will require which treatment in the future? Select one: a. Vitamin K b. Warfarin c. Continual heparin infusion d. Aspirin Feedback

Warfarin this clot is due to stasis of blood flow in her venous circulation. Heparin is used for the prevention of a clot, but has to be infused. is anticoagulation occurs by heparin binding to antithrombin III and the subsequent inactivation of thrombin. A continuous heparin drip is impractical. Warfarin is used to inhibit the formation of vitamin K clotting factors and would prevent the formation of any clot. Aspirin is used to prevent activation of platelets. e current clot is not due to activation of platelets. Vitamin K will be used to restore clotting factors that may be decreased after warfarin treatment. is patient has sufficient clotting factors as evidenced by her venous clot.

A 63-year-old woman returned to work following a vacation in New Zealand. Several days after returning home, she awoke with swelling and pain in her right leg and her leg was blue. She went immediately to the emergency room where an examination showed an extensive deep vein thrombosis involving the femoral and iliac veins on the right side. Following resolution of the clot, this patient will require which treatment in the future? Select one: a. Vitamin K b. Aspirin c. Warfarin d. Continual heparin infusion

Decreasing preload Ischemic cardiac pain is produced when oxygen demand is greater than the oxygen that can be delivered by the coronary arteries. Under normal circumstances an increase in contractility will increase oxygen demand, but in a dilated heart, an increase in contractility actually decreases oxygen demand. In heart failure, positive inotropic agents reduce oxygen demand by reducing end- diastolic volume (preload) and thus the wall stress that must be developed by the heart with each beat. Reducing volume decreases wall stress because, according to the law of Laplace, the wall stress is proportional to the product of force and radius (which is proportional to ventricular volume).

A 63-year-old woman with congestive heart failure is given digitalis. Positive inotropic drugs can reduce ischemic cardiac pain (angina) in a dilated failing heart by doing which of the following? Select one: a. Increasing diastolic filling time b. •Increasing coronary blood flow c. Decreasing preload d. Increasing heart rate e. Decreasing total peripheral resistance

Prolonged systolic ejection The patient presents with a systolic murmur with ejection click is most indicative of aortic stenosis. The ejection click occurs due to a stiff, calcified valve opening with very high pressures. With a calcified vessel there is delayed closure of the aortic valve, with very high pressure and turbulent flow through the stenotic valve. The location of the murmur and radiation to the neck are classic for aortic stenosis. This outflow obstruction leads to an increase in left ventricular (LV) systolic pressure, as demonstrated in the diagram. As a compensatory mechanism to normalize LV wall stress, LV wall thickness increases by parallel replication of sarcomeres, producing concentric hypertrophy. Increased LV mass and increased systolic pressure lead to a delayed closure of the aortic valve.

A 65-year-old male is brought into the emergency department after suddenly passing out on the street. The patient is now awake and alert. His vital signs are normal. On physical examination, a crescendo-decrescendo systolic murmur with ejection click is heard at the right upper sternal border, with radiation to the neck. The patient is immediately scheduled for an echocardiogram. How does this patient's cardiac cycle differ from normal? Select one: a. Decreased atrial filling b. Prolonged systolic ejection c. Decreased wall thickness d. Decreased isovolumic relaxation e. Decreased isovolumetric contraction

Inhibition of the Na+-K+pump is increased

A 65-year-old male on digoxin for atrial fibrillation is told by his physician to get a blood analysis for K+ on a regular basis because hypokalemia will increase his risk of digitalis toxicity. In the presence of hypokalemia, the risk of digitalis toxicity is increased because of which of the following? Select one: a. Inhibition of the Na+-K+pump is increased b. The excitability of nerve cells is increased c. The intracellular potassium concentration of red blood cells is increased d. The amplitude of nerve cell action potentials is increased e. The membranes of cardiac muscle cells are hypopolarized

Gastroileal reflex Relaxation of the ileocecal sphincter occurs with or shortly after eating. THis reflex has been termed thegastroileal reflex. It is not clear whether the reflex is mediated by gastrointestinal hormones (gastrin and cholecystokinin) or extrinsic autonomic nerves to the intestine. Note that the gastroileal reflex is named with the origin of the reflex first (gastro) and the target of the reflex named second (ileal). THis method of naming is characteristic of all the gastrointestinal reflexes. THe enterogastric reflex involves signals from the colon and small intestine that inhibit gastric motility and gastric secretion. THe gastrocolic reflex causes the colonto evacuate when the stomach is stretched. THe intestino-intestinal reflex causes a bowel segment to relax when it is overstretched. THe rectosphincteric reflex is also called the defecation reflex.

A 65-year-old man eats a healthy meal. Approximately 40 min later the ileocecal sphincter relaxes and chyme moves into the cecum. Gastric distention leads to relaxation of the ileocecal sphincter by way of which reflex? Select one: a. Intestino-intestinal reflex b. Gastrocolic reflex c. Gastroileal reflex d. Enterogastric reflex e. Rectosphincteric reflex

Decreased alveolar PO% Decreased alveolar PO2 will cause an increase in pulmonary vascular resistance, leading to pulmonary hypertension.

A 65-year-old man with emphysema due to 34 years of cigarette smoking is admitted to hospital due to dyspnea. With further tests the mean pulmonary arterial pressure is determined to be 45 mm Hg at rest. He is hypoxic (PO% % 49 mm Hg), hypercapnic (85 mm Hg), and slightly acidotic. ! e cardiovascular and oxygen changes are due to which of the following? Select one: a. Decreased pulmonary resistance b. Increased parasympathetic activity c. Decreased pH d. Decreased alveolar PO% e. Increased arterial PCO2

Aortic regurgitation

A 66-year-old male is referred to a cardiologist for evaluation. Physical examination reveals a diastolic murmur prominent over the left sternal border, a decrease in diastolic pressure, and an increase in pulse pressure. Which of the following is the most likely diagnosis? Select one: a. Aortic regurgitation b. Aortic stenosis c. Mitral valve prolapse d. Pulmonic stenosis e. Pulmonary regurgitation

Lipase The process of fat digestion begins in the stomach and is completed in the proximal small intestine, predominately by enzymes synthesized and secreted by the pancreatic acinar cells. The major lipolytic pancreatic enzyme is the carboxylic esterase, known as lipase. Full activity requires the protein cofactor colipase, as well as an alkaline pH, bile salts, and fatty acids.

A 67-year-old male with a history of alcohol abuse presents to the emergency room with severe epigastric pain, hypotension, abdominal distension, and diarrhea with steatorrhea. Serum amylase and lipase are found to be greater than normal, leading to a diagnosis of pancreatitis. The steatorrhea can be accounted for by a decrease in the intraluminal concentration of which of the following pancreatic enzymes? Select one: a. Chymotrypsin b. Lipase c. Trypsin d. Colipase e. Amylase

left atrial pressure It is usually not feasible to measure the left atrial pressure directly in the normal human being because it is difficult to pass a catheter through the heart cham- bers into the left atrium. e balloon-tipped, flow directed catheter (Swan-Ganz catheter) was devel- oped nearly 30 years ago to estimate left atrial pressure for the management of acute myocardial infarction. When the balloon is inflated on a Swan-Ganz catheter, the pressure measured through the catheter, called the wedge pressure, approximates the left atrial pressure for the following reason: blood flow distal to the cath- eter tip has been stopped all the way to the left atrium, which allows left atrial pressure to be estimated. e wedge pressure is actually a few mm Hg higher than the left atrial pressure, depending on where the cath- eter is wedged, but this still allows changes in left atrial pressure to be monitored in patients with left ventricular failure.

A 67-year-old man is admitted as an emergency to University Hospital because of severe chest pain. A Swan-Ganz catheter is floated into the pulmonary artery, the balloon is inflated, and the pulmonary wedge pressure is measured. !e pulmonary wedge pressure is used clinically to monitor which of the following pressures? Select one: a. Pulmonary artery diastolic pressure b. Left ventricular pressure c. Left atrial pressure d. Pulmonary artery systolic pressure e. Pulmonary capillary pressure

An increased a wave The a wave is the increase in central venous pressure that normally occurs during atrial con- traction. Mitral regurgitation will produce a greater atrial preload and therefore a greater force of contraction. The increased atrial volume pro- duces an increased ventricular preload. Blood pressure is typically normal in patients with mitral regurgitation. The greater left ventricular preload produces a greater-than-normal stroke volume. However, the forward stroke volume, the volume entering the aorta, does not increase, so there is no increase in pulse pressure or cardiac output.

A 67-year-old man who has difficulty breathing when he exercises makes an appointment to see his physician. Auscultation reveals a holosystolic murmur leading to the diagnosis of mitral regurgitation. Which of the following laboratory findings is most likely to be present? Select one: a. An increased cardiac output b. An increased pulse pressure c. A decreased arterial pressure d. A decreased left ventricular preload e. An increased a wave

625 mL/min The clearance of PAH is a good estimate of renal plasma flow (RPF) because, under normal circum- stances, almost all (more than 90%) of the PAH passing through the kidney is excreted. If the clearance of PAH is 90% of the actual renal blood flow, then the true renal blood flow is approximately 695 mL/min.

A 68-year-old woman presents with hypertension and oliguria. A CT of the abdomen reveals a hypoplastic left kidney. Based on the following laboratory data, which of the following is her estimated renal plasma flow? Renal artery PAH = 6 mg/dLRenal vein PAH = 0.6 mg/dLUrinary PAH = 25 mg/mLUrine flow = 1.5 mL/minHematocrit = 40% Select one: a. 475 mL/min b. 625 mL/min c. 550 mL/min d. 700 mL/min e. 775 mL/min

E When there is a blockage of an airway there is no movement of fresh air. erefore the air in the alveoli reaches an equilibration with pulmonary arterial blood. erefore, PO2 will decrease from 100 to 40, PCO2 will increase from 40 to 45, and systemic PO2 will decrease because there is a decrease in oxygen uptake from the alveoli and thus decreased O2 diffusion from the alveoli.

A child has been eating round candies approximately 1 and 1.5 cm in diameter and inhaled one down his airway blocking his left bronchiole. Which of the following will describe the changes that occur? Select one: a. A b. B c. C d. D e. E

Ammonium H. pylori is a bacterium that accounts for 95% of patients with duodenal ulcer and virtually 100% of patients with gastric ulcer when chronic use of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDS) are eliminated. H. pylori is characterized by high urease activity, which metabolizes urea to NH3 (ammonia). Ammonia reacts with H! to become ammonium (NH4). "THis reaction allows the bacterium to withstand the acid environment of the stomach. THe ammonium production is believed to be the major cause of cytotoxicity because the ammonium directly damages epithelial cells, increasing the permeability of the gastric mucosal barrier. Bile salts and NSAIDS can also damage the gastric mucosal barrier, but these are not directly related to H. pylori infection. Pepsin can exacerbate the mucosal lesions cause by H. pylori infection, but pepsin levels are not increased by H. pylori . It should be clear that gastrin does not mediate the mucosal damage caused by H. pylori .

A 68-year-old woman with hematemesis has heartburn and stomach pain. Endoscopy shows inflammation involving the gastric body and antrum as well as a small gastric ulcer. Biopsies were positive for Helicobacter pylori. H. pylori damages the gastric mucosa primarily by increasing mucosal levels of which substance? Select one: a. Gastrin b. Pepsin c. Bile salts d. NSAIDS e. Ammonium

It inhibits both gastrin- and acetylcholine-mediated secretion of acid Histamine (H2) receptor antagonists inhibit both gastrin-induced and vagal-mediated secretion of acid. Secretion of acid by gastric parietal (oxyntic) cells involves stimula- tion of adenyl cyclase and cyclic AMP-mediated stimulation of the active transport of chloride and potassium-hydrogen ion exchange. Neither gas- trin nor vagal stimulation activates adenyl cyclase directly; both depend on concomitant release of histamine and histamine-induced activation of adenyl cyclase.

A 68-year-old woman with rheumatoid arthritis, who has been taking nonsteroidal anti-inflammatory drugs (NSAIDS) for the past 10 years, complains of burning epigastric pain that is relieved by antacids, but worsened with food. Her doctor discontinues the NSAIDS and starts her on cimetidine. Which of the following is true regarding the pharmacological blockade of histamine H2 receptors in the gastric mucosa? Select one: a. It inhibits both gastrin- and acetylcholine-mediated secretion of acid b. It inhibits gastrin-induced but not meal-stimulated secretion of acid c. It causes an increase in potassium transport by gastric parietal (oxyntic) cells d. It has no effect on either gastrin-induced or meal-stimulated secretion of acid e. It prevents activation of adenyl cyclase by gastrin

Absorption of Na+ in the colon is under hormonal (aldosterone) control Both the absorption of Na+ and secretion of K+ from the colon are affected by changes in circulating levels of aldosterone. The major route of absorption of sodium in the colon is electrogenic transport. Because of the "tight" nature of the tight junctions that connect cells in the colon, a relatively large potential difference exists between the mucosal (negative) and serosal (positive) surfaces of the absorptive cells. This electrical difference favors the net secretion of K+ into the lumen. Secretion of HCO3- occurs in exchange for absorption of Cl-. No counterbalancing cation exchange pumps are present in the colon.

A 70-year old woman presents with abdominal pain, microcytic anemia, and weight loss. Colonoscopy with biopsy confirms colon cancer. Which of the following statements about the colon is correct? Select one: a. The luminal potential in the colon is positive b. Bile acids enhance absorption of water from the colon c. Absorption of Na+ in the colon is under hormonal (aldosterone) control d. Net absorption of HCO3 − occurs in the colon e. Net absorption of K+ occurs in the colon

Infusion of a balanced electrolyte solution With severe diarrhea, there is a large loss of sodium and water from the body resulting in dehy- dration and sometimes shock. e best therapy is to replace the electrolytes that were lost during diar- rhea. erefore, infusion of a balanced electrolyte solution is the therapy of choice.

A 70-year-old man enters the hospital emergency department and has been experiencing severe diarrhea. He has pallor, tachycardia, and an arterial pressure of 80/50, and has trouble walking. Which of the following therapies would the physician recommend to prevent shock? Select one: a. Infusion of a sympathomimetic drug b. Administration of an antihistamine c. Blood infusion d. Administration of a glucocorticoid e. Infusion of a balanced electrolyte solution

B Neither plasma gastrin levels nor the rate of acid secretion are diagnostic for duodenal ulcer. However, when duodenal ulcer patients are pooled together they exhibit a statistically significant increase in the rate of acid secretion and a statistically significant decrease in plasma gastrin levels. How is this possible? "e basal and maximal acid secretion rates of normal subjects range from 1 to 5 mEq/hr and from 6 to 40 mEq/hr, respectively, which overlaps with the basal (2-10 mEq/hr) and maximal (30-80 mEq/hr) acid secretion rates of duodenal ulcer patients. "e increase in acid secretion of the average duodenal ulcer patient suppresses the secretion of gastrin from the antrum of the stomach. It should be obvious that endoscopy is diagnostic for duodenal ulcer

A 71-year-old man with hematemesis and melena has a cresenteric ulcer in the duodenum. Lavage dislodged the clot, revealing an underlying raised blood vessel, which was successfully eradicated via cautery with a bipolar gold probe. Which of the following factors are diagnostic for duodenal ulcer? Select one: a. A b. D c. C d. B e. E

Intrinsic factor Intrinsic factor is a glycoprotein secreted from parietal cells (i.e., acid secreting cells in the stomach) that is necessary for absorption of vitamin B12. " e patient has a diminished capacity to secrete acid because of chronic gastritis. Because acid and intrinsic factor are both secreted by parietal cells, a diminished capacity to secrete acid is usually associated with diminished capacity to secrete intrinsic factor. Ptyalin, also knownas salivary amylase, is an enzyme that begins carbohydrate digestion in the mouth. " e secretion of ptyalin is not aff ected by gastritis. Rennin, known also as chymosin, is a proteolytic enzyme synthesized by chief cells in the stomach. Its role in digestion is to curdle or coagulate milk in the stomach, a process of considerable importance in very young animals. It should be clear that saliva secretion is not aff ected by gastritis. Trypsin is a proteolytic enzyme secreted by the pancreas.

A 71-year-old man with upper abdominal pain and blood in the stool takes NSAIDS for the pain and washes it down with whiskey. Pentagastrin administration produced lower than predicted levels of gastric acid secretion. Secretion of which of the following substances is most likely to be diminished in this patient with gastritis? Select one: a. Saliva b. Rennin c. Ptyalin d. Trypsin e. Intrinsic factor

3 Point (3) marks the end of systole and the beginning of diastole. he ventricles begin to relax, and part way through diastole the atria contract. Pressure in the left ventricle and aorta both begin to fall as blood travels through systemic circulation. Once the pressure in the ventricle falls below the pressure in the aorta, the aortic valve closes (3). This is where the murmur of aortic regurgitation begins. An incompetent aortic valve allows blood to flow backwards into the left ventricle through the aortic valve.

A 76-year-old male presents to his primary care physician with exertional dyspnea that has been worsening over the past four months. He is no longer able to do any household chores. He has also had swelling in his legs. He does not use pillows, but has been sleeping in a reclining chair for >10 years. He reports that he has no other medical problems, but that he has not seen a physician in more than 40 years. He does not take any medications. His family history is notable for a father with a bicuspid aorta. He has a 20-pack year smoking history and denies using any illicit drugs. Temperature 37°C (98.6°F), heart rate 80/min, blood pressure 132/68 mmHg, respiratory rate 18/min, and oxygen saturation 94% on room air. On physical exam, he bobs his head and has a pulsating uvula. He has a soft S1, an early diastolic decrescendo murmur at the right upper sternal border that increases with leaning forward, a diastolic rumble at the apex, and an S3. The PMI is diffuse and laterally displaced. There is a rapid rise and fall of the carotid pulses and crackles are noted in the bases of the lung bilaterally. The jugular venous pulse is approximately 10 cm and there is 1+ peripheral edema. A normal cardiac cycle is depicted in the diagram. The abnormal murmur in this patient begins at which numbered point of the cardiac cycle? Select one: a. 2 b. 1 c. 5 d. 6 e. 4 f. 3

Sodium

A 78-year-old man presents to his primary care physician with swelling in his legs. He says he has trouble breathing when he lies flat and wakes up in the middle of the night short of breath. His physician diagnoses him with congestive heart failure and prescribes a new medication; however, the patient returns to the clinic 2 weeks later because of side effects associated with the new medication. He reports nausea, vomiting, and changes in his vision that include seeing yellow halos around lights. The physician becomes concerned about drug toxicity related to the new medication. Which of the following intracellular ion concentrations increases as a direct result of the newly prescribed drug? Select one: a. Sodium b. Calcium c. Chloride d. Hydrogen e. Magnesium

increase A cell equilibrated in 300 mOsmol/kg sodium chloride means that the cell can be placed in a solution containing 300 mOsmol/kg of a nonpermeant solute without undergoing a change in volume. However, when the cell is placed in a solution containing a permeant molecule (e g., glycerol, urea), the molecule will diffuse into the cell and add to the intracellular osmolarity, i.e., the osmotic effect of the permeant molecule in the external fluid is eliminated after a certain period of time. Because glycerol is a permeant molecule, the glycerol will diffuse into the cell, causing the intracellular osmolarity to become 600 mOsmol/kg, which will lead to an increase in cell volume. There is no change in cell volume initially (prior to glycerol diffusion into the cell) because the cell is placed into an iso-osmotic solution of glycerol

A cell is equilibrated in an aqueous solution of 300 mOsmol/kg sodium chloride. Which of the following best describes what will happen to cell volume when the cell is placed in an aqueous solution of 300 mOsmol/kg glycerol? Select one: a. Increase and then decrease b. Increase c. Decrease and then increase d. Decrease e. No change

GLIP-induced insulin release GLIP is released by the presence of fat, carbohydrate, or protein in the gastrointestinal tract. GLIP is a strong stimulator of insulin release and is responsible for the observation that an oral glucose load releases more insulin and is metabolized more rapidly than an equal amount of glucose administered intravenously. Intravenously administered glucose does not stimulate the release of GLIP. Neither CCK nor VIP stimulates the release of insulin. GLIP does not stimulate glucagon release, and glucagon has the opposite effect of insulin, that is, it would decrease the rate of glucose clearance from the blood. VIP does not stimulate GLIP release.

A clinical experiment is conducted in which one group of subjects is given 50 g of glucose intravenously and another group is given 50 g of glucose orally. Which of the following factors can explain why the oral glucose load is cleared from the blood at a faster rate compared to the intravenous glucose load? (CCK, cholecystokinin; GLIP, glucose-dependent insulinotropic peptide; VIP, vasoactive intestinal peptide) Select one: a. CCK-induced VIP release b. GLIP-induced insulin release c. GLIP-induced glucagon release d. VIP-induced GLIP release e. CCK-induced insulin release

C THe various secretagogues, which include acetylcholine, gastrin, and histamine, have a multiplicative or synergistic effect on gastric acid secretion. THis means that histamine potentiates the effects of gastrin and acetylcholine, and that H2 blockers attenuate the secretory responses to both acetylcholine and gastrin. Likewise, acetylcholine potentiates the effects of gastrin and histamine, and atropine attenuates the secretory effects of histamine and gastrin. "erefore, in the experiment described, the stimulation of acid secretion by pentagastrin is attenuated by the H2 blocker because of this multiplicative effect of the secretagogues.

A clinical study is conducted in which gastric acid secretion is stimulated using pentagastrin before and after treatment with a histamine H2 blocker. Which of the following rates of gastric acid secretion (in mEq/hr) is most likely to have occurred in this experiment? Select one: a. A b. E c. C d. B e. D

the child could be the natural offspring of this couple There is no antigen and antibody reaction between the anti-B antibodies and the red cells. ere is a reac- tion between the anti-B antibodies and the red cells. erefore the red cells have the B antigen and must be type B. ere is no antigen and antibody reaction between the anti-D antibodies and the red cells. ere- fore the red cells must be Rh-negative. e child is blood type B- . Since father is AB- and the mother is B -, the child could be B-

A couple requests blood typing of their 2-year-old child (father AB, Rh-negative; mother B, Rh-negative). Results of hemagglutination assays of the child's blood are shown in the next figure. Which of the following conclusions concerning the child's parentage is valid? Select one: a. Neither the father nor the mother could be the natural parents b. the child could be the natural o ffspring of this couple c. the mother could be the natural mother, but the father could not be the natural father d. the father could be the natural father, but the mother could not be the natural mother

Arterial compliance The difference between systolic pressure and diastolic pressure is called the pulse pressure. e two main factors that affect pulse pressure are stroke volume and arterial compliance. Pulse pressure is directly proportional to the stroke volume and inversely pro- portional to the arterial compliance. us, a decrease in arterial compliance would tend to increase pulse pressure.

A decrease in which of the following tends to increase pulse pressure? Select one: a. Venous return b. Systolic pressure c. Stroke volume d. Arterial compliance e. Plasma volume

Prevent of an action potential Na+ channels must open to depolarize the membrane and generate an action potential. If these channels are blocked, an action potential cannot occur. An increase in the rate of depolarization (choice A) could only occur if the rate of entry of positive charges into the cell was increased. This could occur if more Na+ channels were open or if another positive ion such as Ca2+ entered the cell during depolarization. Conversely, the rate of depolarization could also increase if negative charges left the cell during the depolarization phase. This action would also increase the speed at which the inside of the cell became positive relative to the outside. An increase in the rate of repolarization (choice B) could occur if more K+ channels were opened or there was an increase in Na+/K+ pump activity. Following depolarization, the K+ channels open and there is an efflux of K+that reduces the membrane potential. The Na+/K+ pump then acts to reestablish the resting membrane potential by pumping 3 Na+ out of the cell for every 2 K+ it pumps into the cell. Because repolarization is the result of K+ channels opening, a drug that inhibits Na+ channel opening would not inhibit repolarization (choice C). A reduction in the amplitude of the action potential (choice E) is not possible. Action potentials are all-or-none and always the same amplitude. All-or-none means that they occur or do not, but there is no partial occurrence. Once an action potential is generated, it propagates without decrement down the membrane. A graded potential, however, does vary in amplitude and does decrease in amplitude over distance.

A drug that blocks Na+ channels is applied to a nerve cell. Electrodes are used to measure voltage changes in the membrane before and following drug administration. The expected effect on the action potential would be which of the following? Select one: a. Increase the rate of depolarization b. Increase the rate of repolarization c. Reduce the amplitude of the action potential d. Prevent of an action potential e. Inhibit repolarization

Hyponatremia The upstroke of the action potential is caused by an inward flow of sodium ions, and therefore its magnitude depends on the extracellular sodium concentration. Decreasing the external Na+ concen- tration decreases the size of the action potential, but has little effect on the resting membrane potential because the permeability of the membrane to Na+ at rest is low. Conversely, increasing the external K+ concentration decreases the resting membrane potential. Changes in external Ca2+ con- centration affect the excitability of nerve and muscle cells, but not the magnitude of the resting potential or the action potential.

A fireman suffers extensive burns, resulting in a fluid and electrolyte imbalance. Which of the following conditions will produce a decrease in the magnitude of a nerve membrane action potential? Select one: a. Hypernatremia b. Hypokalemia c. Hyponatremia d. Hyperkalemia e. Hypocalcemia

44 In a patient who is hemorrhaging, which of the following of the following is an adaptive response that helps to maintain mean arterial pressure?

A fluid shift from interstitial to vascular compartments

calcitonin The vignette describes a lipophilic hormone that directly diffuses through cell membranes and acts by binding to its intracellular or nuclear hormone receptor. Out of the available answer choices, the only hormone that does not bind to the described intracellular or nuclear receptor is calcitonin. Instead, the calcitonin receptor is a member of the seven-transmembrane G-protein-coupled receptors (GPCRs). Binding of the calcitonin receptor by calcitonin leads to activation of signal transduction mediated by intracellular second messengers, such as cAMP. cAMP subsequently activates downstream protein kinases, which ultimately leads to the physiologic effects of calcitonin. Calcitonin is synthesized by the parafollicular cells (also known as C-cells) of the thyroid and functions to: Decrease blood calcium levels by direct inhibition of bone resorption Enhance calcium excretion by the kidney Examples of hormones that act through the GPCR and cAMP-mediated signal transduction include FSH/LH, TSH, ACTH, ADH, PTH, and glucagon. Aldosterone, vitamin D, cortisol, and T3 are examples of hormones that cross the plasma membrane and bind to an intracellular or nuclear receptor. The resulting hormone-receptor complex acts as a transcription factor and promotes gene transcription and subsequent protein synthesis. Other hormones that act through intracellular or nuclear receptors include testosterone, estrogen, and progesterone. The image shows the signaling pathway of a steroid hormone.

A group of scientists is investigating a class of hormones in laboratory rats. These hormones circulate in the bloodstream and directly pass through the cell and nuclear membrane to bind to its receptor in the nucleus. The scientists have developed an assay to analyze the activity of these hormones by assessing mRNA levels of known downstream products in various tissues.Which of the following hormones utilizes a different receptor mechanism than the one described? Select one: a. Vitamin D b. T3 c. Cortisol d. Calcitonin e. Aldosterone

D the lower zones of the lung ventilate better than the upper zones and the middle zones have intermediate ventilation. These differences in regional ventilation can be explained by regional differences in pleural pressure. e pleural pressure is typically about 10 cm H2O in the upper regions and about 2.5 cm H2O in the lower regions. A less negative pleural pres- sure in the lower regions of the chest cavity causes less expansion of the lower zones of the lung during resting conditions. erefore, the bottom of the lung is rela- tively compressed during rest but expands better during inspiration compared to the apex.

A healthy 10-year-old boy breathes quietly under resting conditions. His tidal volume is 400 ml and ventilation frequency is 12/min. Which of the following best describes the ventilation of the upper, middle, and lower lung zones in this boy? Select one: a. A b. B c. C d. D e. E

Internal intercostals and abdominal recti Contraction of the internal intercostals and abdomi- nal recti pull the rib cage downward during expiration. e abdominal recti and other abdominal muscles compress the abdominal contents upward toward the diaphragm, which also helps to eliminate air from the lungs. e diaphragm relaxes during expiration. e ex- ternal intercostals, sternocleidomastoid muscles, and scaleni increase the diameter of the chest cavity during exercise and thus assist with inspiration, but only the diaphragm is necessary for inspiration during quiet breathing.

A healthy, 25-year-old medical student participates in a 10-km charity run for the American Heart Association.Which of the following muscles does the student use (contract) during expiration? Select one: a. Diaphragm and external intercostals b. Sternocleidomastoid muscles c. Scaleni d. Diaphragm and internal intercostals e. Diaphragm only f. Internal intercostals and abdominal recti

A positive

A lady presented with shock due to Post partum hemorrhage, her blood group was unknown but became coagulatedwhen mixed with serum containing anti-A antibodies and similarly her serum coagulated with B positive blood. The mostsuitable blood group to be transfused in this case is: Select one: a. AB positive b. A positive c. B positive d. O positive e. O negative

is more compliant Compliance is the change in volume per change in pressure. Compliance is due to "elastic forces of the lung tissue and . . . elastic forces caused by surface tension of the fluid that lines the inside walls of the alveoli." If a person is being ventilated with a liquid then there is a lack of elastic forces due to surface tension. erefore the compliance is decreased.

A liquid-ventilated lung compared to a gas-ventilated lung Select one: a. is more compliant b. has a reduced airway resistance c. has a more pronounced hysteresis d. requires greater pressure to inflate e. has increased residual volume

+105 Note that lead III has the strongest vector, there- fore the mean electrical axis will be closer to this lead than to leads I or II. e angle of lead III is 120°, and the resultant vector (mean electrical axis) is close to that lead and has a value of 105°.

A male long-term smoker who is 62 years old weighs 250 lb. He had the following EKG recorded at his local hospital. Which of the following is the mean electrical axis calculated from standard leads I, II, and III shown in his EKG? Select one: a. +105 b. +90 c. -20° d. -110° e. +180

150 beats/min The heart rate can be determined by 60 divided by the R-R interval, which gives you a value of 150 beats/ min. is is tachycardia, defined as a heart rate greater than 100 beats/min.

A male patient had a myocardial infarction at age 55. He is now 63 years old. Standard limb lead I is shown here. What is his heart rate? Select one: a. 40 beats/min b. 50 beats/min c. 100 beats/min d. 75 beats/min e. 150 beats/min

Transcription of genes Steroid hormones enter cells and bind to receptor proteins. The receptor-hormone complex binds to specific response elements, or the regulatory region of DNA, and activates gene transcription.

A mass is felt in the groin of an infant girl during a physical examination. Surgical resection shows that it is a testicle. The baby is diagnosed with testicular feminization syndrome. In this syndrome, androgens are produced but cells fail to respond to the steroid hormones because they lack appropriate intracellular receptors.After binding intracellular receptors, steroids regulate the rate of which of the following? Select one: a. Protein translation b. Transcription of genes c. Initiation of protein synthesis d. mRNA processing e. mRNA degradation

Unitary (single unit) Smooth Muscle (syncytial smooth muscle or visceral smooth muscle

A mass of hundreds to thousands of smooth muscle fibers that contract together as a single unit

Sites of ion exchange

A medical student in histology class is studying the peripheral nervous system. While viewing a specimen under high magnification, she notices that the neurons have interruptions in the myelin sheath at regular intervals along the length of their axons. Which of the following is the primary function of the gaps described? Select one: a. Sites of low membrane capacitance b. Sites of ion exchange c. Sites of phagocytosis d. Sites of neurotransmitter release e. Sites of insulation

+10 Net filtration pressure (NFP) = (capillary hydrostatic pressure + interstitial colloid osmotic pressure) − (capillary colloid osmotic pressure + interstitial hydrostatic pressure). With the given values, interstitial colloid osmotic pressure equals 10 mm Hg, based on the following: 8 = (22 + X) − (17 + 7) = 22 + X − 24 = X − 2. When solved: X = 8 + 2 = 10

A medical student is studying fluid exchange in the skeletal muscle capillaries of a laboratory animal. He determines that fluid is being forced out of the capillaries with a net filtration pressure of 8 mm Hg, and he obtains the following laboratory values: Capillary hydrostatic pressure = 22 mm Hg Capillary colloid osmotic pressure = 17 mm Hg Interstitial hydrostatic pressure = 7 mm Hg Which of the following is the interstitial colloid osmotic pressure in mm Hg? Select one: a. - 6 b. +6 c. - 9 d. +8 e. +10

Chylomicrons Long-chain fatty acids are extruded from enterocytes in the form of chylomicrons into the lymphatic system. Triglycerides are hydrolyzed to monoglycerides and taken into mucosal cells. If the fatty acids are short chains (less than 10 to 12 carbon atoms), they are extruded in the form of free fatty acids into the portal blood. Chylomicrons represent triglycerides and esters of cholesterol that have been invested in the intestinal mucosa with a coating of phospholipid, protein, and cholesterol.

A morbidly obese male presents with hypertension, hyperlipidemia, and Type II diabetes mellitus. Dietary fat, after being processed, is extruded from the mucosal cells of the gastrointestinal tract into the lymphatic ducts in the form of which of the following? Select one: a. Chylomicrons b. Diglycerides c. Monoglycerides d. Triglycerides e. Free fatty acids

the child has no chance of developing Hemolytic disease of the newborn (HDN) HDN occurs when the mother is Rh- , the father is Rh+ , resulting in an Rh- child. Since the child is O- and the father is Rh -, there is no chance of HDN.

A mother of blood type A+ who has always been perfectly healthy just delivered her second child. !e father is of blood group O-. Knowing that the child is of blood group O- (O, Rh-), what would you expect to find in this child Select one: a. the child has no chance of developing Hemolytic disease of the newborn (HDN) b. the child will suffer from both A and B c. the child will suffer from erythroblastosis fetalis due to ABO blood group incompatibility d. the child will su ffer from erythroblastosis fetalis due to rhesus incompatibility

+60 mV The Nernst equation is used to calculate the equilibrium potential for a single ion. In applying the Nernst equation, we assume that the membrane is freely permeable to that ion alone. ENa+ = 2.3 RT/zF log Ce/Ci = 60 mV log 140/14 = 60 mV log 10 = 60 mV. Notice that the signs were ignored and that the higher concentration was simply placed in the numerator to simplify the log calculation. To determine whether ENa+ is +60 mV or -60 mV, use the intuitive approach—Na+ will diffuse from extracellular to intracellular fluid down its concentration gradient, making the cell interior positive.

A muscle cell has an intracellular [Na+] of 14 mM and an extracellular [Na+ ] of 140 mM. Assuming that 2.3 RT/F = 60 mV, what would the membrane potential be if the muscle cell membrane were permeable only to Na+? Select one: a. 0 mV b. -60 mV c. +60 mV d. 80 mV e. +80 mV

Primary active transport H+ secretion by gastric parietal cells occurs by H+-K+-adenosine triphosphatase (ATPase), a primary active transporter.

A new drug is developed that blocks the transporter for H+ secretion in gastric parie tal cells. Which of the following transport processes is being inhibited? Select one: a. Primary active transport b. Cotransport c. Simple diffusion d. Facilitated diffusion e. Countertransport

Sigmoid colon Hirschsprung disease is characterized by a congenital absence of ganglion cells in the distal colon resultingin a functional obstruction. Most cases of Hirschsprung disease are diagnosed in the newborn period. Hirschsprung disease should be considered in any newborn who fails to pass meconium within 24 to 48 hr after birth. Although contrast enema is useful in establishing the diagnosis, rectal biopsy remains the criterion standard. Aganglionosis begins with the anus, which is nearly always involved, and continues proximally for a variable distance. Both the myenteric (Auerbach) and submucosal (Meissner) plexus are absent, resulting in reduced bowel peristalsis and function. The precise mechanism underlying the development of Hirschsprung disease is poorly understood.

A newborn boy does not pass meconium in the first 24 hr. His abdomen is distended and he begins vomiting. Various tests lead to a diagnosis of Hirschsprung disease. An obstruction is most likely found in which portion of the gut? Select one: a. Sigmoid colon b. Lower esophageal sphincter c. Pylorus d. Ascending colon e. Ileocecal sphincter

Parasympathetic ganglion cells Hirschsprung disease results from the absence of parasympathetic ganglion cells in the myenteric and submucosal plexus of the rectum and/or colon. Congenital aganglionosis begins with the anus, which is always involved, and continues proximally for a variable distance. Both the myenteric (Auerbach) and submucosal (Meissner) plexus are absent, resulting in reduced bowel peristalsis and function. " e precise mechanism underlying the development of Hirschsprung disease is unknown. It should be clear that an absence of lymphatic endothelial cells, capillary endothelial cells, or red blood cells would not aff ect colonic motility.

A newborn boy has a distended abdomen, fails to pass meconium within the first 48 hr of life, and vomits repeatedly. Analysis of a rectal biopsy provides a definitive diagnosis of Hirschsprung disease. The absence of which type of cell is diagnostic for Hirschsprung disease? Select one: a. Lymphatic endothelial cells b. Red blood cells c. Parasympathetic ganglion cells d. Capillary endothelial cells e. Smooth muscle cells

SGLT 1 The transport protein responsible for the sodium-dependent glucose transport in the small intestine is termed the SGLT1 (Na+-glucose transporter). The absorption of glucose occurs through the coordinated action of transport proteins located in the brush border and basolateral membranes of the enterocyte. Glucose uptake into the enterocyte from the lumen of the GI tract occurs primarily via the sodium-dependent SGLT1 secondary active transport mechanism. Glucose exit from the enterocyte into the extracellular fluid occurs by facil- itated diffusion and is mediated by the membrane transporter, Glut-2. The Na+-glucose cotransporter also transports galactose. Thus, when the cotransporter is congenitally defective, the resulting glucose and galactose malabsorption causes severe diarrhea that can be fatal if glucose and galac- tose are not removed from the diet. A similar secondary active transport process (Na+-glucose cotransport) occurs in the renal tubules via SGLT1 and SGLT2. Glut-5 is the membrane transporter located on the apical por- tion of the enterocyte responsible for the facilitated entry of fructose into the cell.

A newborn with severe diarrhea is found to have an inherited defect in a glucose transporter resulting in glucose/galactose malabsorption, necessitating a glucose- and galactose-free diet. Which of the following is the transport protein responsible for entry of glucose into the intestinal enterocyte? Select one: a. Glut-5 b. SGLT 2 c. Glut-2 d. SGLT 1 e. SGLT 5

Decrease the rate of rise of the upstroke of the action potential Blockade of the Na+ channels would prevent action potentials. The upstroke of the action potential depends on the entry of Na+ into the cell through these channels and therefore would also be reduced or abolished. The absolute refractory period would be lengthened because it is based on the availability of the Na+ channels. The hyperpolarizing afterpotential is related to increased K+ permeability. The Na+ equilibrium potential is calculated from the Nernst equation and is the theoretical potential at electrochemical equilibrium (and does not depend on whether the Na+ channels are open or closed).

A newly developed local anesthetic blocks Na+ channels in nerves. Which of the following effects on the action potential would it be expected to produce? Select one: a. Shorten the absolute refractory period b. Decrease the rate of rise of the upstroke of the action potential c. Increase the Na+ equilibrium potential d. Decrease the Na+ equilibrium potential e. Abolish the hyperpolarizing after - potential

faster in ↑ fiber size, in better myelination

propagation of action potentials are faster or slower in increased fiber size?

The cardiac action potential passes through the AV node The PR interval starts at the beginning of the P wave and ends at the beginning of the QRS complex. The physiologic events that occur during this time period include atrial depolarization, which is responsible for the P wave, AV nodal depo- larization, and depolarization of the bundle of His and the Purkinje fibers. SA nodal depolarization precedes the P wave. Since the mass of the SA node is so small, this event cannot be detected on the standard ECG recording. The mitral and aortic valves are closed during isovolemic con- traction, which occurs after the QRS complex has begun. The second heart sound occurs at the end of systole.

A pacemaker is inserted in a patient in order to shorten the PR interval detected on their ECG. Which of the following events normally occurs during the PR interval? Select one: a. The ventricle is contracting b. There is no change in the voltage tracing on the ECG c. The second heart sound is heard d. The mitral and aortic valves are both closed e. The cardiac action potential passes through the AV node

Bile reabsorption in the small intestine

A patient complains of residue in her underwear. She also notes her stool floats and smells worse than normal. From her history, it is known she had a bowel resection of the terminal ileum one month ago. She evades answering the question whether she follows the dietary guidelines that were provided after the surgery. It is explained that her symptoms are not unexpected and most likely due to the decrease in which of the following? Select one: a. Bile reabsorption in the small intestine b. Pancreatic lipase secretion c. Cholecystokinin release d. Bile release into the small intestine e. De novo bile acid synthesis

1500 ml Residual volume = FRC - ERV = 3 L - 1.5 L = 1.5 L

A patient has a dead space of 150 ml, functional residual capacity of 3 L, tidal volume of 650 ml, expiratory reserve volume of 1.5 L, total lung capacity of 8 L, and respiratory rate of 15 breaths/min. What is the residual volume? Select one: a. 6500 ml b. 500 ml c. 1500 ml d. 2500 ml e. 1000 ml

Hypothalamic tumor secreting large amounts of TRH A hypothalamic tumor secreting large amounts of TRH would stimulate the pituitary gland to secrete increased amounts of TSH. As a result, the secretion of thyroid hormones would increase, and this would result in an elevated heart rate. In comparison, a pa- tient with either a pituitary tumor secreting large amounts of TSH or Graves' disease would have low plasma levels of TRH because of feedback. Both TRH and TSH levels would be elevated in endemic goiter, but the heart rate would be depressed because of the low rate of T4 secretion.

A patient has a goiter associated with high plasma levels of both thyrotropin-releasing hormone (TRH) and thyroid-stimulating hormone (TSH). Her heart rate is elevated. THis patient most likely has which of the following? Select one: a. Graves' disease b. Pituitary tumor secreting large amounts of TSH c. Endemic goiter d. Hypothalamic tumor secreting large amounts of TRH

Patient is taking thyroid extract If a subject were taking sufficient amounts of exog- enous thyroid extract to increase plasma levels of T4 above normal, feedback would cause TSH secretion to decrease. Low plasma levels of TSH would result in atrophy of the thyroid gland. In Graves' disease, the same changes in plasma levels of T4 and TSH would be present, but the thyroid gland would not be atrophied. In fact, goiter is often present in patients with Graves' disease. A lesion in the anterior pituitary that prevents TSH secretion or the taking of propylthiouracil or large amounts of iodine would be associated with low plasma levels of T4.

A patient has an elevated plasma thyroxine (T4 ) concentration, a low plasma thyroid-stimulating hormone (TSH) concentration, and a thyroid gland that is smaller than normal. Which of the following is the most likely explanation for these findings? Select one: a. Patient is consuming large amounts of iodine b. Patient has Graves disease c. Patient is taking thyroid extract d. Patient has a lesion in the anterior pituitary that prevents TSH secretion e. Patient is taking propylthiouracil

Distance of diffusion

A patient has signs of arterial hypoxemia. According to Fick's law of diffusion, an increase in which of the following factors will cause a decrease in the oxygen diffusion rate from the alveoli to the capillaries? Select one: a. Body temperature b. Oxygen partial pressure difference c. Fat solubility of the gas d. Alveolar surface area e. Distance of diffusion

Obstruction of the common bile duct When plasma biliru- bin is increased due to bile duct obstruction, it is generally the conjugated form of bilirubin that increases due to reabsorption of bilirubin glu- curonide into the blood.

A patient is found to have elevated levels of direct-acting plasma bilirubin. Which of the following is the most likely diagnosis? Select one: a. Terminal ileal bypass b. Pancreatitis c. Tropical sprue d. Obstruction of the common bile duct e. Bile reflux gastropathy

1091 mL/min Effective renal plasma flow (RPF) is calculated from the clearance of para-aminohippuric acid (PAH) [CPAH = UPAH × V/PPAH = 600 mL/min]. Renal blood flow (RBF) = RPF/1 - hematocrit = 1091 mL/min.

A patient is infused with paraaminohippuric acid (PAH) to measure renal blood flow (RBF). She has a urine flow rate of 1 mL/min, a plasma [PAH] of 1 mg/mL, a urine [PAH] of 600 mg/mL, and a hematocrit of 45%. What is her "effective" RBF? Select one: a. 1091 mL/min b. 660 mL/min c. 600 mL/min d. 1333 mL/min

A Primary excessive secretion of aldosterone (Conn's syndrome) would be associated with marked hypoka- lemia and metabolic alkalosis (increased plasma pH). Because aldosterone stimulates sodium reabsorption and potassium secretion by the cortical collecting tubule, there could be a transient decrease in sodium excretion and an increase in potassium excretion, but under steady-state conditions, both urinary sodium and potassium excretion would return to normal to match the intake of these electrolytes. However, the sodium retention as well as the hypertension associ- ated with aldosterone excess would tend to reduce renin secretion.

A patient is referred for treatment of hypertension. After testing, you discover that he has a very high level of plasma aldosterone, and your diagnosis is Conn's syndrome. Assuming no change in electrolyte intake, which of the following changes would you expect to find, compared with normal? Select one: a. A b. B c. C d. D e. E

C This diagram depicts cardiac (ventricular) function and venous function curves. With the onset of exercise, there is an increase in contractility, which shifts the cardiac function curve up. Changes often occur in tandem - exercise = inotropy+ decrease in TPR to maximize CO Also accompanying the onset of exercise are decreases in total peripheral resistance and venous compliance, both of which shift the vascular function curve to the right and increase its slope. The point at which the cardiac function and venous function curves inter- sect (C) represents the central venous pressure and cardiac output of the cardiovascular system under these conditions.

A patient is referred to the Heart Station for exercise stress testing. Baseline and exercise levels of cardiac and venous function are measured and plotted on the graphs below. The point marked "Control" represents baseline cardiovascular function in the resting state in the supine position. During treadmill exercise, there will be a shift from the resting state to which of the following points? Select one: a. A b. E c. B d. C e. D

Iron deficiency anemia the blood count values show that the patient is anemic. Her bone marrow is functioning and she has a normal platelet count, but is generating a decreased number of abnormal RBCs. e microcytic (small), hypochromic (decreased intracellular hemoglobin) is a classic description of iron deficiency anemia. With renal failure the patient would be anemic with normal RBCs. Sickle cell anemia has misshapen RBCs. Mega- loblastic anemia is characterized by macrocytic (large) RBCs.

A patient presents to your office complaining of extreme fatigue and shortness of breath on exertion that has gradually worsened over the past 2 weeks. On physical examination, you observe a well-nourished woman who appears comfortable but somewhat short of breath. Her vital signs include a pulse of 120, respiratory rate of 20,and blood pressure of 120/70. When she stands up her pulse increases to 150 and her blood pressure falls to 80/50. Her hematologic values are Hgb 7 g/dL, Hct 20%, RBC count 2 x 106/μl, platelet count of 400,000/μl. On a peripheral smear, her RBCs are microcytic and hypochromic. What would be your diagnosis of this patient? Select one: a. Sickle cell anemia b. Renal failure c. Megaloblastic anemia d. Iron deficiency anemia e. Aplastic anemia

Decreased lower esophageal sphincter tone Delayed gastric emptying, hiatal hernia, and decreased esophageal motility are all causes of GERD, but the most likely cause of GERD in this patient is a relaxed or incompetent lower espophageal sphincter (LES), which allows the gastric contents to reflux into the esophagus. The hydrochloric acid from the stomach irritates the esophageal walls, producing the substernal pain of indigestion, called heartburn. Causes of decreased LES tone include alcohol, cigarettes, coffee (caffeine), and chocolate, as well as certain drugs (nitrates and calcium channel blockers) and hormones (estrogen and prog- esterone). The LES is comprised of smooth muscle at the junction of the esophagus and the stomach. The upper esophageal sphincter is located between the pharynx and the esophagus and is comprised of skeletal muscle.

A patient presents with a chronic cough. The history and physical findings rule out postnasal drip, asthma, and other pulmonary disease. Upon questioning, the patient also reports substernal burning pain that is most pronounced after ingestion of coffee, chocolate, french fries, and alcohol. Which of the following is the most likely cause of gastroesophageal reflux disease (GERD) in this patient? Select one: a. Decreased esophageal motility b. Hiatal hernia c. Decreased lower esophageal sphincter tone d. Delayed gastric emptying e. Decreased upper esophageal sphincter tone

Easily breakable clot Fibrin monomers polymerize to form a clot. To make a strong clot requires the presence of fibrin- stabilizing factor that is released from platelets within the clot. e other clotting tests determine the activa- tion of extrinsic and intrinsic pathways or number of platelets.

A patient suffers from a congenital deficiency in factor XIII (fibrin-stabilizing factor). What would analysis of his blood reveal? Select one: a. Prolonged whole blood clotting time b. Prolonged partial thromboplastin time c. Prolonged prothrombin time d. Easily breakable clot

It produces its effect by increasing distal tubular permeability to sodium Aldosterone binds to an intracellular receptor that causes an increased synthesis of a variety of proteins, including K+ and Na+ ion chan- nels and Na+-K+-ATPase, which together act to increase Na+ reabsorption and K+ secretion by the tubular cells of the distal nephron. The secretion of H+ is also enhanced by aldosterone. Aldosterone secretion is stimulated by a decrease in blood volume (through the renin-angiotensin system) and by increased plasma K+ concentrations.

A patient undergoing surgery develops an increase in the secretion and plasma levels of ACTH, cortisol, and aldosterone. Which of the following statements about aldosterone is correct? Select one: a. It has its main effect on the proximal tubule b. It produces its effect by activating cAMP. c. It causes an increased reabsorption of hydrogen ion d. It produces its effect by increasing distal tubular permeability to sodium e. It is secreted in response to an increase in blood pressure

nothing An Rh- mother will generate antibodies to the Rh+ red blood cells after the birth of the first child that is Rh+ . In the scenario presented, the mother has not been exposed to Rh+ RBCs so she has not devel- oped antibodies. However, after the birth of this child, and if the child is found to be Rh+, then anti-D immunoglobulin should be administered to the mother to destroy any fetal RBCs to which she has been exposed and to prevent her from forming antibodies to the Rh+ (D) antigen.

A pregnant woman comes in for a visit. She is AB Rh- and her husband is A Rh+ . this is her first child. What should be done at this time? Select one: a. Administer anti-D immunoglobulin to the mother at this time b. Nothing c. Administer anti-D immunoglobulin to the child if the child is Rh+ d. Administer anti-D immunoglobulin to the mother after delivery e. Administer anti-D immunoglobulin to the child after delivery

Hyperosmolality of duodenal contents initiates a decrease in gastric emptying Gastroparesis is delayed emptying of food from the stomach, and is a common cause of gastroesophageal reflux disease (GERD). The rate of gastric emptying depends upon neural (enterogastric reflex) and hormonal inhibitory feedback from the proximal small bowel. Gastroparesis is com- mon in diabetes mellitus because hyperosmolality of the duodenum initi- ates a decrease in gastric emptying, which is probably neural in origin and is sensed by duodenal osmoreceptors. Because solids must be liquefied prior to emptying from the stomach, the gastric emptying of liquids begins before the emptying of solids. Emptying is fastest with a carbohydrate meal, and slowest after a fatty meal. Acid in the antrum inhibits gastrin secretion, which may inhibit gastric motility. The vagus mediates receptive relaxation, the process in which the fundus and upper portion of the body of the stomach relax in response to movement in the pharynx and esopha- gus in order to accommodate food that enters the stomach.

A patient with diabetes mellitus presents with gastroesophageal reflux disease accompanying gastroparesis. Which of the following statements about gastric emptying is correct? Select one: a. Vagal stimulation decreases receptive relaxation in the upper portion of the stomach b. Acidification of the antrum increases gastric emptying c. Solids empty more rapidly than liquids d. Meals containing fat empty faster than carbohydrate-rich food e. Hyperosmolality of duodenal contents initiates a decrease in gastric emptying

A proton pump inhibitor Withdrawal from long-term use of proton pump inhibitors prescribed for peptic ulcer dis- ease may be associated with rebound gastric hypersecretion. Pharmacolog- ical suppression of gastric acid secretion can occur when the administered drug binds to a receptor present on the parietal cell or when it antagonizes the hydrogen-potassium-ATPase pump responsible for the active secretion of hydrogen ion into the gastric lumen. At the present time, the most effec- tive antisecretory compounds work by blocking the histamine type-2 (H2) receptor present on the parietal cell or by inhibition of the hydrogen pumps. The latter are the most potent and long-acting, thus increasing the probability of increasing serum gastrin.

A patient with peptic ulcer disease is taken off their medication because of undesirable side effects. As a result, the patient has rebound gastric acid hypersecretion. Which of the following drugs best accounts for the observed result? Select one: a. A cholinergic receptor antagonist b. A proton pump inhibitor c. An H1-receptor antagonist d. An antacid e. A CCKB receptor antagonist

C In a patient with a very high rate of renin secretion, there would also be increased formation of angiotensin II, which in turn would stimulate aldosterone secretion. e increased levels of angiotensin II and aldosterone would cause a transient decrease in sodium excretion, which would cause expansion of the extracellular fluid volume and increased arterial pressure. the increased arterial pressure as well as other compensations would return sodium excretion to normal so that intake and output are balanced. erefore, under steady-state con- ditions, sodium excretion would be normal and equal to sodium intake. e increased aldosterone concentration would cause hypokalemia (decreased plasma potassium concentration), whereas the high level of angiotensin II would cause renal vasoconstriction and decreased renal blood flow.

A patient with severe hypertension (blood pressure 185/110 mm Hg) is referred to you. A renal magnetic resonance imaging scan shows a tumor in the kidney, and laboratory findings include a very high plasma renin activity of 12 ng angiotensin 1/ml/hr (normal = 1). the diagnosis is a renin-secreting tumor. Which of the following changes would you expect to find in this patient, under steady-state conditions, compared with normal? Select one: a. A b. B c. C d. D e. E

D Surfactant is formed relatively late in fetal life. Pre- mature babies born without adequate amounts of surfactant can develop pulmonary failure and die. Surfactant is a surface active agent that greatly reduces the surface tension of the water lining the alveoli. Water is normally attracted to itself, which is why rain- drops are round. By reducing the surface tension of the water lining the alveoli (and thus reducing the ten- dency of water molecules to coalesce), the surfactant reduces the work of breathing, i.e., less transpulmo- nary pressure is required to inhale a given volume of air. Because compliance is equal to the change in lung volume for a given change in transpulmonary pres- sure, it should be clear that pulmonary compliance is decreased in the absence of surfactant.

A preterm infant has a surfactant deficiency. Without surfactant, many of the alveoli collapse at the end of each expiration, which in turn leads to pulmonary failure. Which of the following sets of changes are present in the preterm infant, compared to a normal infant? Select one: a. A b. B c. C d. D e. E f. F g. G

It occurs in response to cholecystokinin Cholecystokinin is released from the upper small intestine in response to partially hydrolyzed dietary lipids and proteins and promotes gallbladder emptying. Gallbladder contraction and sphincter of Oddi relaxation are necessary for delivery of bile into the duodenum. These muscular actions are under both hormonal and neural control. Cholecystokinin contracts gallbladder smooth muscle by a direct action on the muscle and through activation of vagal afferent fibers leading to a vago-vagal reflex. Relaxation of sphincter of Oddi smooth muscle occurs via activation of inhibitory enteric nerves. Gallbladder con- traction is also promoted by vagal stimulation, which is cholinergically mediated and blocked by the muscarinic receptor antagonist, atropine.

A patient's abdominal pain is subdued after eating. Which of the following is true regarding contraction of the gallbladder following a meal? Select one: a. It occurs in response to cholecystokinin b. It is stimulated by atropine c. It is inhibited by a fat-rich meal d. It occurs simultaneously with the contraction of the sphincter of Oddi e. It is inhibited by the presence of amino acids in the duodenum

20 mm Hg Each gram of hemoglobin can normally carry 1.34 milliliters of oxygen. Hb 12 g//dL. Arterial oxygen content 12 * 1.34 16 ml O2/dL. Using 12 ml O2/dL yields a mixed venous saturation of 25%. With a satu- ration of 25% the venous PO2 should be close to 20 mm Hg.

A person with anemia has a hemoglobin (Hb) concentration of 12 g/dL. He starts exercising and uses 12 ml O2 /dL. What is the mixed venous PO2 ? Select one: a. 10 mm Hg b. 40 mm Hg c. 100 mm Hg d. 0 mm Hg e. 20 mm Hg

21.4 L Intracellular fluid volume is calculated as the difference between total body fluid (0.57 x 60 kilograms = 34.2 kilograms, or approximately 34.2 L) and extracellular fluid volume (12.8 L), which equals 21.4 L.

A person with normal body fluid volumes weighs 60 kg and has an extracellular fluid volume of approximately 12.8 L, a blood volume of 4.3 L, and a hematocrit of 0.4; 57% of his body weight is water. Answer the following three questions based on this information. What is the approximate intracellular fluid volume? Select one: a. 21.4 L b. 23.5 L c. 25.6 L d. 19.6 L e. 17.1 L

20 Normal alveolar PCO2 is 40 mm Hg. Nor- mal alveolar ventilation for this person is 3.6 L/min. On the ventilator the alveolar ventilation is 7.2 L/min. A doubling of alveolar ventilation results in a decrease in alveolar PCO2 by one-half. us alveolar PCo2 would be 20.

A person's normal tidal volume is 400 ml with a dead space of 100 ml. !e respiratory rate is 12 breaths/min. The person is placed on ventilator for surgery and the tidal volume is 700 with a rate of 12. What is the approximate alveolar PCO% for this person? Select one: a. 30 b. 10 c. 40 d. 50 e. 20

She has been taking anabolic steroid supplements for 5 years Anabolic steroids bind to testosterone receptors in the hypothalamus, providing feedback inhibition of normal ovarian cycling and preventing menstrual cycling, as well as stimulation of osteoblastic activity in the bones.

A professional athlete in her mid-20s has not had a menstrual cycle for 5 years, although a bone density scan revealed normal skeletal mineralization. Which of the following facts elicited during the taking of her medical history may explain these observations? Select one: a. She has been taking anabolic steroid supplements for 5 years b. Her plasma estrogen concentration is very low c. Her blood pressure is greater than normal d. Her grandmother suff ered a hip fracture at age 79 e. She consumes a high-carbohydrate diet

250 mmol urea If a red blood cell is placed in a hypotonic solution, the cell will swell until its osmolarity equals the osmolarityof the extracellular fluid. The tonicity of the extracellular solution is equal to the osmolarity of those particles within the extracellular solution that are not permeable to the cell membrane. Because urea is able to permeatethe cell membrane, its effective osmotic pressure is zero. Therefore, red blood cellsplaced in a urea solution will swell until hemolyzed. The osmolarity of the NaCl solution is approximately the same (300 mmol) asthat of the red blood cell and, therefore, will not cause any change in intracellular volume.

A red blood cell will swell the most when it is placed in a solution containing Select one: a. 100 mmol calcium chloride b. 200 mmol potassium chloride c. 300 mmol mannitol d. 250 mmol urea e. 150 mmol sodium chloride

Removal of sarcoplasmic Ca++ Skeletal muscle contraction is tightly regulated by the concentration of Ca++ in the sarcoplasm. As longas sarcoplasmic Ca++ is sufficiently high, none of the remaining events—removal of acetylcholine fromthe neuromuscular junction, removal of Ca++ from the presynaptic terminal, closure of the acetylcholinereceptor channel, and return of the dihydropyridine receptor to its resting conformation—would have anyeffect on the contractile state of the muscle.

A single contraction of skeletal muscle is most likely to be terminated by which of the following actions? Select one: a. Removal of Ca++ from the terminal of the motorneuron b. Removal of sarcoplasmic Ca++ c. Closure of the postsynaptic nicotinic acetylcholine receptor d. Removal of acetylcholine from the neuromuscular junction e. Return of the dihydropyridine receptor to its resting conformation

ADH

A solute gradient must be present and _______ stimulates incorporation of aquaporins into the luminal membrane of the collecting duct epithelial cells

Chloride channels Cholera toxin causes an irreversible increase in cAMP levels in enterocytes, which leads to an irreversible opening of chloride channels on the luminal surface. Movement of chloride into the gut lumen causes a secondary movement of sodium ions through paracellular pathways into the gut lumen. Water follows the osmotic gradient causing a tremendous increase in fluid loss into the gut lumen, which results in severe diarrhea.

A tsunami tidal wave hits the east coast of South America and the people living there are forced to drink unclean water. Within the next several days, a large number of people develop severe diarrhea and about half of these people expire. Samples of drinking water are positive for Vibrio cholerae. Which of the following types of ion channels is most likely to be irreversibly opened in the epithelial cells of the crypts of Lieberkühn in these people with severe diarrhea? Select one: a. Sodium channels b. Magnesium channels c. Potassium channels d. Calcium channels e. Chloride channels

aVF The positive portion of lead aVF has an axis of 90° and the negative part of this lead has an axis of 90°. Note the difference between the positive and the negative ends of this vector is 180°.

A ventricular depolarization wave when traveling ! 90° in the frontal plane will cause a large negative deflection in which lead? Select one: a. aVR b. aVL c. Lead II d. aVF e. Lead III

78. A 23-year-old caucasian male is admitted to the hospital following a motorcycle accident. On examination, no bones appear to be broken, but there is Extensive muscle bruising resulting in tissue swelling from increased capillary permeability. His arterial blood pressure is 80/40. He is awake and able to Walk with assistance. Based on this information, it is likely that which of the following will be decreased from normal?

Right atrial pressure

medium sized bronchi

site of highest airway resistance?

102. A 48-year-old man is admitted to the hospital for treatment of idiopathic pulmonary hypertension. The patient has experienced progressive dyspnea over The past 6 months. Cardiac catheterization shows a decrease in cardiac function. The most likely cause of the decreased cardiac function is an increase In which of the following?

Right ventricular afterload

28. Intestinal epithelial cells possess 2 transport mechanisms to move glucose across the plasma membrane, a facilitated glucose carrier (GLUT2) as well as a sodium- dependent secondary active transporter (SGLT1). Which of the following attributes distinguishes these 2 transport modalities with respect to glucose transport?

SGLT1 can transport glucose from a region of low to a region of high concentration

exchange, or antiport eg: Na+-Ca2+ exchange - Ca++ out; digitalis - blocks indirectly

solutes move in opposite directions?

Isosmotic solutions

solutions that have the same calculated osmolarity?

E If ADH receptors are blocked, then more water is excreted in the urine. This will lead to a decrease in the volume of fluid in both the intracellular and extracellular compartments. Water moves from ICF to ECF, means moves from RBC either.

Antidiuretic hormone (ADH) regulates water retention by acting to increase water reabsorption in the kidneys. If the ADH receptors are antagonized, what effects on intracellular fluid volume, extracellular fluid volume, and hematocrit are expected? Select one: a. A b. B c. C d. D e. E f. F

122. The largest proportional increase in left ventricular afterload and myocardial oxygen consumption is most likely to occur following 20% increase in which Of the following?

Aortic pressure

B Tissue PO2 is a balance between delivery and us- ages. With a decrease in blood flow, with no change in metabolism there will be a decrease in venous PO2 (less delivery but no change in metabolism) and an increase in venous PCO2 (less washout).

Arterial PO2 is 100 mm Hg and arterial PCO2 is 40 mm Hg. Total blood flow to all muscle is 700 ml/min. THere is a sympathetic activation resulting in a decrease in blood flow to 350 ml/min. Which of the following will occur? Select one: a. A b. B c. C d. D e. E f. F g. G

15. A state-mandated blood screening test conducted on day 2 of life in healthy full-term newborn shows a decreased serum thyroxine [T4] concentration And a normal serum thyroid-stimulating hormone [TSH] concentration. Tests on venous blood confirm these findings. The venous free T4 concentration is Normal. Which of the following is the most likely explanation for these results?

Thyroxine-binding globulin deficiency

99. A family is found to have a novel genetic disorder characterized by elevated insulin levels and frequent hypoglycemia brought on by even brief periods of Fasting. A group of investigators discovers that they carry a mutation involving a potassium channel expressed in pancreatic beta cells. This abnormality causes hypoglycemia because it makes the potassium channels overly sensitive to their normal, activity-modulating regulatory Substance. Which of the following substances binds directly to these channels to regulate their activity?

ATP

Pancreatic lipase Absorption of the fat-soluble vitamins (A, D, E, and K) is diminished if there is a lack of pancreatic lipase. Lipase is required to produce monoglycerides that, in combination with bile salts, make it possible to bring the fat-soluble vitamins close to the mucosal cell surface for absorption. With the exception of vitamin B12, which is absorbed bound to intrinsic factor in the ileum, vitamins are absorbed chiefly in the upper small intestine.

Absorption of fat-soluble vitamins requires which of the following? Select one: a. Pancreatic amylase b. Chymotrypsin c. Secretin d. Intrinsic factor e. Pancreatic lipase

101. An advertisement promotes energy pars containing fructose as an ideal food to take on extreme mountain-climbing expeditions. Which of the following Statements concerning fructose absorption is true?

Absorption of fructose into an intestinal epithelial cell is by facilitated transport and thus does not require energy

107. Cells of the adrenal medulla secrete catecholamine when the sympathetic nervous system is powerfully stimulated. Which of the following Neurotransmitters are used to activate the chromaffin cells?

Acetylcholine

68. During an experimental study, a researcher isolates a neuromuscular preparation and stimulates the motor nerve in the presence of a small dose of Tubocurarine to achieve a submaximal response. The resulting end-plate potential [EPP] is measured in both 0.9% saline [control] and in the presence of Neostigmine [experimental]. The EPP of the experimental group is incdreased in both amplitude and duration. Which of the following molecular targets is The most likely cause of this effect?

Acetylcholinesterase

Guillain-Barré syndrome

Acute inflammatory demyelinating polyradiculopathy viruses (PNS) Results in: -demyelination of peripheral nerves -symmetric ascending muscle weakness/ paralysis -respiratory failure -cardiac irregularities, -hypertension, -hypotension -sensory abnormalities these are the characteristics of which disease?

Absorption of glucose by intestinal epithelial cells All of the processes listed are examples of primary active transport [and therefore use adenosine triphosphate (ATP) directly], except for absorption of glucose by intestinal epithelial cells, which occurs by secondary active transport (i.e., cotransport). Secondary active transport uses the Na+ gradient as an energy source and, therefore, uses ATP indirectly (to maintain the Na+ gradient).

Adenosine triphosphate (ATP) is used indirectly for which of the following processes? Select one: a. Transport of K+ from extracellular to intracellular fluid b. Transport of Na+ from intracellular to extracellular fluid c. Accumulation of Ca2+ by the sarcoplasmic reticulum (SR) d. Transport of H+ from parietal cells into the lumen of the stomach e. Absorption of glucose by intestinal epithelial cells

Inhibition of NaCl co-transport in the early distal tubules Thiazide diuretics inhibit NaCl co-transport in the luminal membrane of the early distal tubules.

Administration of a thiazide diuretic (e.g., chlorothiazide) would be expected to cause which of the following effects as its primary mechanism of action? Select one: a. Inhibition of Na# -2Cl" -K# co-transport in the loop of Henle b. Inhibition of Na# -2Cl" -K# co-transport in the collecting tubules c. Inhibition of the renal tubular actions of aldosterone d. Inhibition of NaCl co-transport in the proximal tubules e. Inhibition of NaCl co-transport in the early distal tubules

they stimulate the activity of osteoblasts Estrogen compounds are believed to have an osteoblast-stimulating effect. When the amount of estrogen in the blood falls to very low levels after menopause, the balance between the bone-building activity of the osteoblasts and the bone-degrading activity of the osteoclasts is tipped toward bone deg- radation. When estrogen compounds are added as part of hormone replacement therapy, the bone- building activity of the osteoblasts is increased to balance the osteoclastic activity.

After menopause, hormone replacement therapy with estrogen-like compounds is effective in preventing the progression of osteoporosis. What is the mechanism of their protective effect? Select one: a. they increase absorption of calcium from the gastrointestinal tract b. they stimulate calcium reabsorption by the renal tubules c. they stimulate the activity of osteoblasts d. they stimulate parathyroid hormone secretion by the parathyroid gland

T tubules

Also called transverse tubules, these are deep invaginations of the plasma membrane found in skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell.

Collateral impulses from higher brain centers Because strenuous exercise does not change significantly the mean arterial PO2, PCO2, or pH, it is unlikely that these play an important role in stimulat- ing the immense increase in ventilation. Although the mean venous PO2 decreases during exercise, the venous vasculature does not contain chemoreceptors that can sense PO2. e brain, on transmitting motor impulses to the contracting muscles, is believed to transmit collateral impulses to the brain stem to excite the respiratory center. Also, the movement of body parts during exercise is believed to excite joint and muscle proprioceptors that then transmit excitatory impulses to the respiratory center.

Alveolar ventilation increases several-fold during strenuous exercise. Which of the following factors is most likely to stimulate ventilation during strenuous exercise? Select one: a. Increased mean arterial PCO% b. Decreased mean venous PO% c. Decreased mean arterial pH d. Collateral impulses from higher brain centers e. Decreased mean arterial PO%

A deficiency in the brush border enzyme lactase Lactase is a brush border enzyme that hydrolyzes milk sugar (lactose) into glucose and galactose. Patients with a lactase deficiency may experience diarrhea, cramps, and intestinal gas. The diarrhea and cramping reflect the osmotic effect of the sugar on water flux across the intestine. Colonic bacteria metabolize lactose to fatty acids, CO2, and H2.

An 18-year-old college student reports that she experiences severe abdominal bloating and diarrhea within 1 hour of consuming dairy products. A subsequent H2 -breath test is abnormal. The diarrhea and bloating can best be explained by which of the following? Select one: a. A deficiency in the brush border enzyme lactase b. Carbohydrate-induced secretory diarrhea c. A decrease in exocrine pancreatic secretion d. Decreased intestinal surface area e. Decreased carbohydrate absorption

An increase in both direct and indirect plasma bilirubin Infectious hepatitis is a systemic infection predominantly affecting the liver. When jaundice appears, serum bilirubin rises, and, in most instances, total biliru- bin is equally divided between the conjugated (direct) and unconjugated (indirect) fractions. The bilirubin in serum represents a balance between input from production of bilirubin and hepatic/biliary removal of the pig- ment. Hyperbilirubinemia may result from (1) overproduction of bilirubin; (2) impaired uptake, conjugation, or removal of bilirubin; or (3) regurgita- tion of unconjugated or conjugated bilirubin from damaged hepatocytes or bile ducts. Alkaline phosphatase, which is excreted in bile, increases in patients with jaundice due to bile duct obstruction, but generally not when the jaundice is due to hepatocellular disease. Bile acids are synthesized in the liver by a series of enzymatic teps that also involve cholesterol catabo- lism. Liver disease decreases bile acid synthesis.

An 18-year-old female decides to get a tattoo for her birthday. Two months later she presents with a fever, right upper quadrant pain, nausea, vomiting, and jaundice. Which of the following lab values would most likely be found in a patient with infectious hepatitis? Select one: a. An increase in plasma alkaline phosphatase b. An increase in direct bilirubin, and a decrease in indirect bilirubin in the plasma c. An increase in both direct and indirect plasma bilirubin d. An increase in plasma bile acids e. An decrease in both direct and indirect plasma bilirubin

Ileum Most vitamins are absorbed in the upper small intestine, but vitamin B12 (cobalamin) is absorbed primarily in the terminal ileum. In the stomach, vitamin B12 binds with intrinsic factor, a glycoprotein secreted by the parietal cells of the gastric mucosa. The vitamin B12-intrinsic factor complex is emptied from the stomach and propelled along the small intestine to the terminal ileum, where specific active transporters located on the enterocyte microvilli bind the vitamin B12-intrinsic factor complex and the complex is absorbed across the ileal mucosa. Pernicious anemia is a disease in which there is autoimmune destruction of the parietal cells. Vitamin B12 can also be produced by gastrectomy with removal of the intrinsic factor-secreting tissue or by dis- eases of the terminal ileum. Binding of the Vitamin B12-intrinsic factor complex requires Ca2+. Whereas vitamin B12 and folate absorption are Na+- independent, all seven of the other water-soluble vitamins are absorbed by carriers that are Na+ cotransporters.

An 18-year-old male with pernicious anemia lacks intrinsic factor, which is necessary for the absorption of cyanocobalamin. Vitamin B12 is absorbed primarily in which portion of the GI tract? Select one: a. Duodenum b. Ileum c. Jejunum d. Colon e. Stomach

Bradycardia Muscarine binds to acetyl- choline muscarinic receptors on cardiac and smooth muscle. These are the same receptors activated by the release of acetylcholine by the vagus nerve. Cardiac muscarinic receptors decrease the rate of phase 4 depolarization and therefore, decrease the heart rate. A heart rate less than 60 beats per minute is called bradycardia. Acetylcholine receptors on the skeletal mus- cle end plate are nicotinic receptors and do not respond to muscarine. Dilation of the pupils and hypertension are signs of sympathetic, not parasympathetic activity.

An 18-year-old male, who became ill after eating mushrooms, is brought to the Emergency Department, where he is treated for muscarinic poisoning. Which of the following signs is consistent with muscarinic poisoning? Select one: a. Dilation of the pupils b. Bradycardia c. Skeletal muscle contractures d. Hypertension e. Diuresis

Zona glomerulosa This female patient presents with primary amenorrhea, hypertension, and low potassium. She is diagnosed with a congenital adrenal hyperplasia disorder. From her clinical presentation, we can deduce that she has a 17a-hydroxylase deficiency, which would lead to overproduction of mineralocorticoids secreted from the zona glomerulosa.

An 18-year-old woman is referred to a specialist because she has not yet begun to menstruate. She reports generalized weakness and occasional bouts of nausea and vomiting. Her blood pressure is 160/99 mm Hg, heart rate is 92/min, and respiratory rate is 16/min. Physical examination is noticeable for the lack of breast development consistent with Tanner stage 1. Laboratory studies show a serum potassium level of 2.2 mEq/L. She is diagnosed with a condition that decreases the production of two of the three major adrenal steroid hormones, leading to an excess of only one functioning hormone. In which area of the adrenal gland is this one functioning steroid hormone produced? Select one: a. Medulla b. Zona reticularis c. Capsule d. Zona fasciculata e. Zona glomerulosa

Pulmonary valve stenosis the mean electrical axis of the QRS of this patient is shifted rightward to 170°. "is indicates that the right side of the heart is involved. Both aortic stenosis and mitral regurgitation will cause a leftward shift of the QRS axis. Mitral stenosis will not affect the left ventricle but in severe enough circumstances could cause an increase in pulmonary artery pressure.this would cause an increase in pulmonary capillary pressure at the same time. Tricuspid stenosis will not a ffect the right ventricle. therefore, pulmonary valve stenosis is the only condition that fits this set of symptoms.

An 80-year-old male patient at UMC has been diagnosed with a heart murmur. Chest x-ray shows an enlarged heart but no edema fluid in the lungs. "e mean QRS axis of his EKG is 170°. Pulmonary wedge pressure is normal. What is the diagnosis? Select one: a. Mitral stenosis b. Mitral regurgitation c. Aortic stenosis d. Tricuspid stenosis e. Pulmonary valve stenosis

The potassium conductance will increase An increase in extracellular K+ makes the membrane potential more positive. Depolarizing the membrane opens K+ channels causing an increase in membrane conductance. Prolonged depolarization, whether caused by an increase in extracellular K+ or by an action potential, inactivates Na+ channels, which decreases the excitability of the nerve membrane. The activity of the Na+-K+ pump is reduced in hypokalemia, not hyperkalemia.

An 82-year-old woman is brought to the emergency room complaining of nausea, vomiting, muscle cramps, and generalized weakness. Laboratory analysis reveals significant hyperkalemia. Elevations of extracellular potassium ion concentration will have which of the following effects on nerve membranes? Select one: a. The sodium conductance will increase b. The membrane will become more excitable c. The Na+-K+ pump will become inactivated d. The membrane potential will become more negative e. The potassium conductance will increase

The potassium conductance will increase

An 82-year-old woman is brought to the emergency room complaining of nausea, vomiting, muscle cramps, and generalized weakness. Laboratory analysis reveals significant hyperkalemia. Elevations of extracellular potassium ion concentration will have which of the following effects on nerve membranes? Select one: a. The membrane potential will become more negative b. The potassium conductance will increase c. The Na+-K+ pump will become inactivated d. The sodium conductance will increase e. The membrane will become more excitable

3.5 L/min Cardiac output can be measured by using Fick's principle, which asserts that the rate of uptake of a substance by the body (e.g., O2 consumption in milliliters per minute) is equal to the difference between its concentrations (milliliters per liter of blood) in arterial and venous blood multiplied by the rate of blood flow (cardiac output). This principle is restricted to situations in which arterial blood is the only source of the substance measured. If oxygen consumption by the body at steady state is measured over a period of time and the dif- ference in arterial O2 and venous O2 measured by sampling arterial blood and pulmonary arterial blood (which is fully mixed venous blood), cardiac output is obtained from the expression

An 82-year-old woman was admitted to the hospital with ascites, peripheral edema, and shortness of breath. Cardiac catheterization was ordered and the following values were obtained: Pulmonary artery O2 content = 20 mL/100 mLPulmonary vein O2 content = 12 mL/100 mLOxygen consumption = 280 mL/minStroke volume = 40 mL What is the woman's cardiac output? Select one: a. 8 mL/100 mL b. 3.5 L/min c. 4500 mL/min d. 7.0 L/min e. 2.86 L/min

Gastric acid secretion The use of nonsteroidal anti-inflammatory drugs (NSAIDs) may result in NSAID-associated gastritis or peptic ulceration. Chronic gastritis, by definition, is a histopathological entity characterized by chronic inflammation of the stomach mucosa. When inflammation a ffects the gastric corpus, parietal cells are inhibited, leading to reduced acid secretion. Although diagnosis of chronic gastritis can only be ascertained histologically, the administration of pentagastrin should produce a less than expected increase in gastric acid secretion. Pentagastrin is a synthetic gastrin composed of the terminal four amino acids of natural gastrin plus the amino acid alanine. It has all the same physiologic properties of natural gastrin. Although gastrin and pentagastrin can both stimulate growth of the duodenal mucosa, it should be clear that intravenous pentagastrin would not cause substantial growth in the context of a clinical test. In any case, chronic administration of pentagastrin would not lead to a less than expected growth of the duodenal mucosa. Pentagastrin is not expected to increase gastrin secretion, pancreatic enzyme secretion, or pancreatic growth.

An 82-year-old woman with upper abdominal pain and blood in the stool has been taking NSAIDS for arthritis. Endoscopy revealed patchy gastritis throughout the stomach. Biopsies were negative for Helicobacter pylori. Pentagastrin administered intravenously would lead to a less than expected (i.e., less than normal) increase in which of the following? Select one: a. Gastric acid secretion b. Pancreatic growth c. Gastrin secretion d. Pancreatic enzyme secretion e. Duodenal mucosal growth

An increase in the flow of sodium into the cell Phase-4 depolariza- tion is caused by the activation of a Na+ channel. The channel is activated when the membrane hyperpolarizes in contrast to the Na channel respon- sible for the action potential, which is activated when the cell depolarizes. Potassium conductance decreases during phase-4 depolarization and thus the flow of potassium out of the cell is diminished. However, this change in potassium current is not responsible for phase-4 depolarization. Chloride conductance does not change during phase 4. The Na/Ca exchanger main- tains low intracellular calcium at rest and may reverse its direction and pump calcium into the cell during phase 2 of the cardiac action potential. However, neither the Na/Ca exchanger nor the Na-K pump is involved in phase-4 depolarization.

An 84-year-old woman presents with paroxysmal dizziness, syncope, confusion, and fatigue. Her heart rate did not change when the patient was instructed to perform a Valsalva maneuver. 24-hour Holter monitoring revealed periodic episodes of sinus bradycardia. Phase-4 depolarization of SA nodal cells is caused by which of the following? Select one: a. An increase in the flow of sodium into the cell b. A decrease in the flow of chloride out of the cell c. An increase in the activity of the Na/Ca exchanger d. A decrease in the activity of the Na-K pump e. A decrease in the flow of potassium out of the cell

Cortisol

An excess of ___________, which is produced in the zona fasciculata of the adrenal cortex, would lead to Cushing syndrome. Cushing syndrome manifests with hypertension, weight gain with central obesity, fatigue, skin thinning, and psychological disturbances (depression, anxiety). Excess cortisol production would not lead to a lack of sexual maturation.

Reactive hyperemia

An increase in blood flow in response to or reacting to a prior period of decreased blood flow

decrease The airways are tethered to the surrounding tissues, which causes them to be pulled open when the lungs expand - "radial traction" - explains why it is easier for a person with obstructive pulmonary disease to breathe at higher than normal lung volumes.

An increase in pulmonary volume causes a __________________ in airway resistance, which means that airway diameter increases.

Hydraulic conductivity of the capillary wall and Capillary hydrostatic pressure The two main factors that increase lymph flow are an increase in capillary filtration rate and an increase in lymphatic pump activity. An increase in plasma colloid osmotic pressure decreases capillary filtration rate, interstitial volume and hydrostatic pressure, and lymph flow. In contrast, an increase in hydraulic con- ductivity of the capillary wall and capillary hydrostatic pressure increase capillary filtration rate, interstitial volume and pressure, and lymph flow. An increase arteriole resistance would decrease capillary hydrostatic pressure, capillary filtration rate, interstitial volume and pressure, and lymph flow.

An increase in which of the following would tend to increase lymph flow? Select one: a. Plasma colloid osmotic pressure b. Arteriolar resistance c. Hydraulic conductivity of the capillary wall and Capillary hydrostatic pressure d. Capillary hydrostatic pressure e. Hydraulic conductivity of the capillary wall

The resting membrane potential becomes more positive

An investigator is studying the equilibrium potentials of a neuronal cell with a resting membrane potential of -70 mV (VM). The equilibrium potentials are shown below: ENa+ +65 mV ECl- -85 mV ECa2+ +120 mV EK+ -85 mV Which of the following changes occur if the ion permeability to sodium across the cell membrane is increased? Select one: a. The equilibrium potential for potassium (EK+) becomes more positive b. The resting membrane potential becomes more negative c. The equilibrium potential for sodium (ENa+) becomes more positive d. The resting membrane potential becomes more positive e. The equilibrium potential for sodium (ENa+) becomes more negative

114. A 34-year-old woman presents with the recurrent nausea and vomiting. A gastrointestinal motility disorder is suspected, which is confirmed by an Electrogastrogram [see image]. At rest [trace X], it shows inappropriately large depolarizations of the intestinal smooth muscle membrane potentials. Trace Y shows her smooth muscle membrane potentials after administration of a drug. Which of the following drugs most likely caused trace Y?

Antagonist of membrane calcium channel

Its HCO3− concentration increases with secretin stimulation

As part of a large grant studying pancreatic adenocarcinoma, baseline data of pancreatic exocrine secretion are obtained from healthy people. Which of the following findings is expected? Select one: a. Its HCO3− concentration increases with secretin stimulation b. Its osmolality is less than 100 mOsm/kg at average flow rate c. Its Na+ and K+ concentrations increase with increasing flow rate d. Its HCO3− concentration increases with increasing Cl concentration e. Its enzyme concentration is increased with pancreatic polypeptide

repolarization (action potential)

As the membrane reaches its peak voltage, the voltage-gated Na+ channels begin to inactivate, and voltage gated K+ channels begin to open-- this is called?

Increased alveolar PCO2 In a normal person the alveolar gases are the same as the arterial blood. With rebreathing, the exhaled CO2 is never removed and continues to accumulate in the bag. is increase in alveolar and thus arterial PCO2 will be the stimulus for the increased breathing. He will have a decrease alveolar PO2, not increased, with the decreased PO2 stimulating breathing. A decreased PCO2 will not stimulate ventilation. An increased pH, alkalo- sis, will not stimulate ventilation.

At a fraternity party a 17-year-old male places a paper bag over his mouth and breathes in and out of the bag. As he continues to breathe into this bag, his rate of breathing continues to increase. Which of the following is responsible for the increased ventilation? Select one: a. Increased alveolar PO2 b. Increased alveolar PCO2 c. Decreased arterial PCO2 d. Increased pH

Point A

At what point in the Wiggers diagram below does the QRS complex begin? Select one: a. C b. D c. B d. E e. A

5 The hyperpolarizing afterpotential represents the period during which K+ permeability is highest, and the membrane potential is closest to the K+ equilibrium potential. At that point, K+ is closest to electrochemical equilibrium. The force driving K+ movement out of the cell down its chemical gradient is balanced by the force driving K+ into the cell down its electrical gradient.

At which labeled point on the action potential is the K+ closest to electrochemical equilibrium? Select one: a. 1 b. 5 c. 3 d. 4 e. 2

Site E K+ is secreted by the late distal tubule and collecting ducts. Because this secretion is affected by dietary K+, a person who is on a high-K+ diet can secrete more K+ into the urine than was originally filtered. At all of the other nephron sites, the amount of K+ in the tubular fluid is either equal to the amount filtered (site A) or less than the amount filtered (because K+ is reabsorbed in the proximal tubule and the loop of Henle).

At which nephron site does the amount of K+ in tubular fluid exceed the amount of filtered K+ in a person on a high-K+ diet? Select one: a. Site A b. Site B c. Site C d. Site D e. Site E

Point A The Na+ equilibrium potential is approximately +60 mV and is based on the ratio of the intracellular and extracellular Na+ concentrations. During an action potential, the peak of the action potential (point A) is close, but not equal, to the Na+ equilibrium potential. The membrane potential doesn't reach the Na+ equilibrium potential because the Na+ channels start to inac- tivate and the K+ channels begin to activate during the upstroke of the action potential.

At which point on the action potential shown in the diagram below is the membrane closest to the Na+ equilibrium potential? Select one: a. C b. E c. A d. D e. B Feedback

myasthenia gravis

Autoantibodies to postsynaptic ACh receptor (NM) - muscle weakness worsens with muscle use

Multiple Sclerosis

Autoimmune inflammation and demyelination of CNS A cute optic neuritis - painful unilateral visual loss Brain stem/cerebellar syndromes - diplopia, ataxia, scanning speech, intention tremor, nystagmus Pyramidal tract weakness Spinal cord syndromes - neurogenic bladder, paraparesis Symptoms may exacerbate with increased body temperature Relapsing and remitting is most common clinical course women in their 20s and 30s These are characteristics of which disease?

Malignant hyperthermia

Autosomal Dominant condition, more common in children and young adults mutations in RYR1 (ryanodine receptor 1) on chromosome 19 •encodes for a calcium ion release channel •abnormal increase in myoplasmic ionized Ca2+ •There may be dramatic adverse reaction to triggering agent: •inhalational general anesthetics (eg., halothane) •depolarizing muscle relaxants (eg. succinylcholine)

20. A 58-year-old woman comes to the office because of heartburn for two weeks. The pain most often occurs when she lies down to sleep. She also frequently wakes up with burning in her throat and epigastric area. Her temperature is 36.8 C (98 F), pulse is 87/min, respirations are 15/min, and blood pressure is 134/86mmHg. She is treated with omeprazole. After starting this therapy, which changes will occur in this woman for gastric acid secretion, gastrin secretion, and parietal cell carbonic anhydrase (CA) activity?

B

26. An 82-year-old woman with dementia who resides in a nursing care facility is brought to the emergency department 1 hour after she was found to have ingested 20 pills of a drug that inhibits Na+-Cl cotransporters in the distal convoluted tubule. Her blood pressure is 94/58 mm Hg. Physical examination shows dry mucous membranes. Serum studies are most likely to show which of the following sets of findings?

B

62. Serum osmolarity, urine osmolarity, adn urine sodium concentration are measured in six patients who have identical height and weight. Which of the following sets of values was most likely obtained from a patient having inappropriate ADH [vasopressin] secretion?

B

27. A 16-year-old boy participates in a study of exercise and muscle hypertrophy. After a pre training biopsy specimen of the quadriceps muscle is obtained. He begins a weight-lifting program to increase the mass and strength of the quadriceps muscle. After 3 months of training, a second muscle biopsy specimen is taken for histologic assessment of skeletal muscle characteristics. Compared with the pretraining sample, the post-training sample is most likely to show which of the following findings?

B.

Physiologic splitting of S2

Because the aortic valve (A) closes slightly earlier than pulmonic valve (P), the seconds are sometimes heard separately (A2 then P2), more audible during inspiration due to relative lowering of the pressure in the pulmonary artery. This is known as?

Phosphate in the tubules can contribute significantly to titratable acid in the urine Phosphate excretion by the kidneys is controlled by an overflow mechanism. When the transport maximum for reabsorbing phosphate is exceeded, the remaining phosphate in the renal tubules is excreted in the urine and can be used to buffer hydrogen ions and form titratable acid. Phosphate normally begins to spill into the urine when the concentration of extracellular fluid rises above a threshold of 0.8 mmol/L, which is usually exceeded.

Because the usual rate of phosphate filtration exceeds the transport maximum for phosphate reabsorption, which of the following is true? Select one: a. Parathyroid hormone must be secreted for phosphate reabsorption to occur b. More phosphate is reabsorbed than is filtered c. Phosphate in the tubules can contribute significantly to titratable acid in the urine d. All the phosphate that is filtered is reabsorbed e. The "threshold" for phosphate is usually not exceeded

Gastrin The gastrointestinal hormones are secreted from endocrine cells located in the mucosa. The endocrine cells are not clumped together but are dispersed among the epithelial cells, making it virtually impossible to remove surgically the source of any one gastrointestinal hormone. Gastrin is the only listed hormone found in the antrum, but it is also found in the duodenal and to a lesser extent the jejunal mucosa. CCK and secretin secreting endocrine cells are found in the duodenum, jejunum, and ileum. Motilin and GLIP secreting cells are found in the duodenum and jejunum.

Biopsies are taken from the antral and duodenal mucosa of a 65-year-old woman. Which of the following hormones can be found in tissue homogenates from both locations? Select one: a. Cholecystokinin (CCK) b. Secretin c. Gastrin d. Glucose-dependent insulinotropic peptide (GLIP) e. Motilin

57. A 22-year-old woman is brought to the emergency department because of shortness of breath and wheezing for 6 hours. Her symptoms began shortly After visiting her friend who has cats. She has a history of similar symptoms after exposure to cats. On arrival, she speaks in short sentences. Her Respirations are 32/min. Which of the following sets of results is most likely on pulmonary function testing?

C

71. The dashed lines in the letters diagrams show the changes in diameter in afferent and efferent arterioles [solid lines show a normal diameter]. Which of The following will result in increased renal plasma flow and increased glomerular filtration rate?

C

73. An 82-year-old man develops mild shortness of breath 3 months after beginning therapy that includes bleomycin for a localized squamous cell tumor of The mouth. Which of the following pulmonary function test results are most likely to be observed in this patient if you know that bleomycin can cause Pulmonary fibrosis?

C

98. A 20-year-old woman has had pregressive weakness, anorexia, intermittent vomiting, and a 6-kg [13.2-lb] weight loss over the past 6 months. She is thin, Her blood pressure is 88/60 mm Hg, and there is diffuse brown darkening of the elbow creases and in an old appendectomy scar. Which of the following Sets of laboratory findings is most likely in this patient?

C

11. A 25-year-old woman with polycystic kidneys and renal failure has a 3-month history of progressive weakness and fatigue, headaches, hypertension, loss Of appetite, and itching. Her serum creatinine concentration is 4 mg/dL [high]. Which of the following laboratory abnormalities in serum is expected in this patient?

C-

Ca2+ ATPase (SERCA)

Ca2+ is accumulated in the SR by the action of?

RyR ryanodine receptors when the muscle is in the resting state, RyR is blocked by DHPR

Calcium release channel in the SR

Lipid-soluble substances e.g., O2, CO2, steroid hormones

Can cross cell membranes because they can dissolve in the hydrophobic lipid bilayer? Example?

Water-soluble substances e.g., Na+, Cl-, glucose, H2O

Cannot dissolve in the lipid of the membrane, but may cross through water-filled channels, or pores, or may be transported by carriers? Examples?

F Dissolved carbon dioxide combines with water in red blood cells to form carbonic acid, which dissoci- ates to form bicarbonate and hydrogen ions. Many of the bicarbonate ions diffuse out of the red blood cells while chloride ions diffuse into the red blood cells to maintain electrical neutrality. e phenomenon, called the chloride shift, is made possible by a special bicar- bonate-chloride carrier protein in the red cell mem- brane that shuttles the ions in opposite directions. Water moves into the red blood cells to maintain osmotic equilibrium, which results in a slight swelling of the red blood cells in the venous blood.

Carbon dioxide is transported from the tissues to the lungs predominantly in the form of bicarbonate ion. Compared to arterial red blood cells, which of the following best describes venous red blood cells? Select one: a. A b. B c. C d. D e. E f. F g. G h. H i. I

A Most of the carbon dioxide (70%) is transported in the blood in the form of bicarbonate ion. Dissolved carbon dioxide reacts with water to form carbonic acid (mostly in red blood cells), which dissociates into bicarbonate and hydrogen ions. Carbon dioxide also reacts with amine radicals of the hemoglobin molecule to form the compound carbaminohemoglobin, which accounts for about 23% of the carbon dioxide trans- ported in the blood. e remaining carbon dioxide (7%) is transported in the dissolved state.

Carbon dioxide is transported in the blood in the dissolved state, in the form of bicarbonate ion, and in combination with hemoglobin (carbaminohemoglobin). Which of the following best describes the quantitative relationship of these three mechanisms for transporting carbon dioxide in the venous blood under normal conditions (in percentages)? Select one: a. A b. B c. C d. D e. E f. F

Acetazolamide

Carbonic anhydrase inhibitor, blocks Na+, water reabsorption and H+ excretion in the proximal tubule, Increases excretion of HCO3

E The diagram rep- resents the cardiac (ventricular) function and venous function curves. Similar to the familiar Starling curves, cardiac output is graphed as a func- tion of central venous pressure (preload). The cardiac function curves are shifted up and to the left by an increase in contractility and a decrease in afterload; they are shifted down and to the right by a decrease in contrac- tility and an increase in afterload. The vascular function curves graph cen- tral venous pressure as a function of cardiac output. The independent variable, cardiac output, is represented on the y axis. An increase in car- diac output causes a fall in central venous pressure. A decrease in blood volume or venous tone shifts the vascular function curves to the left; an increase in blood volume or venous tone shifts the vascular function curves to the right. The point at which the two curves intersect represents the central venous pressure and cardiac output of the cardiovascular sys- tem. The shift from the resting state to point E represents an increase in vascular volume or venous tone without any change in TPR or ventricular contractility. This is consistent with an infusion of saline or a blood transfusion. An increase in total peripheral resistance (TPR) decreases the slope; a decrease in TPR increases the slope. An increase in TPR decreases the slope of the vascular function curve, and the increase in contractility shifts the cardiac function curve up and to the right. The new intersection of these curves is at point A. The shift from the resting state to point B rep- resents an increase in contractility with no change in TPR. This is consis- tent with the administration of a positive inotropic drug. Upon sudden standing, contractility and TPR increase, whereas venous compliance decreases (i.e., venous tone increases). With exercise, there is an increase in contractility and a decrease in TPR and venous compliance.

Cardiac function and venous function curves were generated in a patient undergoing several maneuvers to evaluate his cardiac and cardiovascular reserves. Starting from the control point, to which point did the curves shift when the person was given a transfusion of saline? Select one: a. D b. C c. E d. B e. A

81. The action potentials shown in the figure below represent those of which kind of cells?

Cardiac nodal cells

18. A 56-year-old man comes to the office due to chronic cough and fatigue. The patient has smoked 2 packs of cigarettes daily since age 18. Physical examination shows cyanosis and expiratory wheezes scattered throughout the lungs. During evaluation for long-term oxygen therapy, his respiratory rate decreases shortly after he begins nasal cannula oxygen supplementation. This patient's reduced respiratory rate after oxygen supplementation is most likely caused by sudden decrease in stimulation of which of the following sensory receptors?

Carotid bodies

Diabetes Insipidus

Central - low ADH, Plasma osmolarity increases, large volumes (up to 15 L/day) of dilute urine are excreted, thirst •Nephrogenic - defect in the response of the kidneys to ADH, ADH levels are higher than normal, Plasma osmolarity increases, large volumes of dilute urine are excreted •. Nephritic syndrome - inflammation of the glomerulus, Hypertension, Oliguria, Hematuria, Proteinuria

49. Healthy adults were given a high fat test meal, and the percent of food that remained in the stomach was measured every 20 minutes after meal Ingestion. The image shows the average results of control test subjects [bottom line] and of subjects who were given an experimental drug [top line] at Doses that simulated a normal physiological response. The drug is most likely a receptor agonist of which of the following gastrointestinal hormones?

Cholecystokinin

7. A 30-year-old male seeks help because he lost weight and feels full after eating only a small amount of food. He is diagnosed with a delay in gastric Emptying. Which of the following hormones has at physiological level the strongest effect in inhibiting gastric emptying?

Cholecystokinin

A Gastrin and CCK do not share any eff ects on gastrointestinal function at normal, physiological conditions; however, they have identical actions on gastrointestinal function when pharmacological doses are administered. Gastrin stimulates gastric acid secretion and mucosal growth throughout the stomach and intestines under physiological conditions. CCK stimulates growth of the exocrine pancreas and inhibits gastric emptying under normal conditions. CCK also stimulates gallbladder contraction, relaxation of the sphincter of Oddi, and secretion of bicarbonate and enzymes from the exocrine pancreas.

Cholecystokinin (CCK) and gastrin share multiple effects at pharmacological concentrations. Which of the following effects do CCK and gastrin share (or not share) at physiological concentrations? Select one: a. E b. D c. A d. B e. C

53. During an experiment, a strain of knockout mouse is developed that has an isolated deficiency of carbonic anhydrase in erythrocytes. No other type of cell Or tissue is deficient in this enzyme. Compared with normal mice, venous blood in the knockout mouse will most likely have a higher concentration of Which of the following substances?

Cl-

Under basal conditions, saliva contains high concentrations of potassium and bicarbonate ions and low concentrations of sodium and chloride ions. "e primary secretion of saliva by acini has an ionic composition similar to that of plasma. As the saliva flows through the ducts, sodium ions are actively reabsorbed and potassium ions are actively secreted in exchange for sodium. Because sodium is absorbed in excess, chloride ions follow the electrical gradient causing chloride levels in saliva to decrease greatly. Bicarbonate ions are secreted by an active transport process causing an elevation of bicarbonate concentration in saliva. "e net result is that, under basal conditions, sodium and chloride concentrations in saliva are about 10% to 15% of that of plasma, bicarbonate concentration is about three-fold greater than that of plasma, and potassium concentration is about seven times greater than that of plasma.

Compared to plasma, saliva has the highest relative concentration of which of the following ions under basal conditions? Select one: a. Potassium b. Chloride c. Bicarbonate d. Sodium

C A premature infant with respiratory distress syn- drome has absent or reduced levels of surfactant. Loss of surfactant creates a greater surface tension. Since surface tension accounts for a large portion of lung elasticity, increasing surface tension will increase lung elasticity making the lung stiffer and less compliant.

Comparing a premature infant with respiratory distress syndrome to a normal full-term infant, how do lung compliance and surfactant levels compare? Select one: a. A b. B c. C d. D e. E f. F

Cardiac output decreases Loss of blood volume shifts the vascular function curve downward, resulting in an operating point at lower pressures and lower cardiac output.

Considering the vascular function curve, what would you expect to happen to cardiac output after a patient experiences hemorrhage. Ignore homeostasis reactions such as those from baroreceptors. Select one: a. Cardiac output increases b. Cardiac output stays the same c. Not enough information to answer d. Cardiac output decreases

29. A new experimental Drug X is observed to alter glomerular filtration rate and filtration fraction. An experiment is performed to evaluate the hemodynamic effects of the drug. The diagram shown is a plot of hydrostatic pressure (Pgc Dashed lines) and oncotic pressure (dotted lines) at various distances along the length of a glomerular capillary. Administration of drug X causes the changes shown. Which of the following best describes the effect of drug X on the renal vasculature?

Constricts the efferent arteriole only

aortic pressure The electrocardiogram (ECG) tracing serves as a reference. The QRS complex marks ventricular depolarization, followed immediately by ventricular con- traction. Aortic pressure increases steeply after QRS, as blood is ejected from the ventri- cles. After reaching peak pressure, aortic pressure decreases as blood runs off into the arteries. The characteristic dicrotic notch ("blip" in the aortic pressure curve) appears when the aortic valve closes. Aortic pressure continues to decrease as blood flows out of the aorta.

Curve A in the figure represents Select one: a. ventricular volume b. aortic pressure c. ventricular pressure d. atrial pressure

ventricular volume Ventricular volume increases slightly with atrial systole (P wave), is constant during isovolumetric contraction (QRS), and then decreases dramatically after the QRS, when blood is ejected from the ventricle.

Curve B in the figure represents Select one: a. left atrial pressure b. atrial pressure c. ventricular pressure d. ventricular volume

Chloride Movement of chloride ions out of cells leads to secretion of fluid by cells. Cystic fibrosis (CF) is caused by abnormal chloride ion transport on the apical surface of epithelial cells in exocrine gland tissues. THe CF transmembrane regulator (CFTR) protein functions both as a cyclic AMP-regulated Cl" channel and, as its name implies, a regulator of other ion channels. " e fully processed form of CFTR is found in the plasma membrane of normal epithelia. Absence of CFTR at appropriate cellular sites is often part of the pathophysiology of CF. However, other mutations in the CF gene produce CFTR proteins that are fully processed but are nonfunctional or only partially functional at the appropriate cellular sites.

Cystic fibrosis (CF) is an inherited disorder of the exocrine glands, affecting children and young people. Mucus in the exocrine glands becomes thick and sticky and eventually blocks the ducts of these glands (especially in the pancreas, lungs, and liver), forming cysts. A primary disruption in the transfer of which ion across cell membranes occurs in CF leading to decreased secretion of fluid? Select one: a. Chloride b. Phosphate c. Calcium d. Potassium e. Sodium

Autodigestion of pancreas Pancreatitis is inflammation of the pancreas. " e pancreas secretes digestive enzymes into the small intestine that are essential in the digestion of fats, proteins, and carbohydrates. Reduced secretion of fluid into the pancreatic ducts in cystic fibrosis cause these digestive enzymes to accumulate in the ducts. " e digestive enzymes then become activated in the pancreatic ducts (which typically would not occur) and can begin to "digest" the pancreas, leading to inflammation and a myriad of other problems (cysts and internal bleeding). Enterokinase is located at the brush border of intestinal enterocytes where it normally activates trypsin from its precursor, trypsinogen. Trypsin inhibitor is normally present in the pancreatic ducts where it prevents trypsin from being activated, and thus prevents autodigestion of the pancreas. When the ducts are blocked in cystic fibrosis, the available trypsin inhibitor is insuffi cient to prevent trypsin from being activated. Excessivesecretion of CCK does not occur in cystic fibrosis. Gallstone obstruction can lead to pancreatitis (by autodigestion) when the obstruction prevents pancreatic juice from entering the intestine, but this isunrelated to cystic fibrosis.

Cystic fibrosis is the most common cause of pancreatitis in children. Which of the following best explains the mechanism of cystic fibrosis-induced pancreatitis? Select one: a. Activation of enterokinase b. Gallstone obstruction c. Autodigestion of pancreas d. Activation of trypsin inhibitor e. Excessive secretion of CCK

10. A 19-year-old man is brought to the emergency department after hitting his head on the pavement when he fell off his motorcycle. An MRI of his head Shows a transection of the pituitary stalk. Which of the following patterns best describes the secretion of pituitary hormones in this patient?

D

14. A 68-year-old man with emphysema comes to the physician for a follow-up. The patient has a long history of heavy cigarette smoking, and pulmonary Function test shows a typical obstructive pattern. He has recently developed chronic hypoxemia. Which of the following patterns of results is most likely to Occur when supplemental oxygen is given to this patient [compared to before supplemental oxygen is given], assuming that respiration rate initially Remains unchanged?

D

42. A normal male subject has a transient increase in blood pressure to 148/88 mmHg after rapid infusion of 2 L of normal saline. Which of the following sets of findings in serum concentrations is the most likely response to this event?

D

55. A healthy 50-year-old man who resides at sea level takes a 45-minute ride in a cable car from near sea level to a ski resort [altitude 3050 m [10,000ft]]. Which of the following labeled points on the diagram best represents this patient 30 minutes after arrival at the resort?

D

56. A healthy 22-year-old man is subject in a study investigating the regulation of heart rate during exercise. He is sitting on a stationary bicycle and is Instructed to begin pedaling in 5 minutes. One minute before he begins to pedal, his heart rate increases. An increase in which of the following Transmitters acting at the indicated receptors best explains the increase in heart rate in this man?

D

67. A 35-year-old man is brought to the emergency department after collapsing in this garage. He recently bought a classic 1960s convertible and was Reparingin it when he collapsed. The patient was inside the garage but had the door half-open. He lost consciousness after working on the car for 2 hours With the engine running. The patient has no known medical problems and takes no medications. He does not use tobacco, alcohol, or illicit drugs. Which Of the following best reflects the combination of finding that would have been expected in an arterial blood sample taken when the patient lost consciousness?

D

2.a 78-year-old man with syncope feels heaviness in his chest with exertion and breathlessness when lying down. A crescendo/decrescendo systolic Murmurs is heard best at the second right intercostal space with radiation to the carotid arteries. Which of the following measurements of left ventricular and aortic pressure is most likely to be found in cardiac catheterization?

D) 150/18 100/50

36. A 65-year-old woman comes to the physician for a follow-up examination after a DEXA scan showed a decrease in bone density. Physician examination shows no abnormalities. Which of the following sets of findings in bone is most likely inthes patient?

D.

13. The resistance of a precapillary arteriole is increased in a muscle vascular bed. Which of the following most likely occurs in response to this increase?

Decreases capillary filtration rate

Hereditary Spherocytosis

Defective spectrin and ankyrin •RBCs adopt a spherical shape and are osmotically fragile, prone to rupture, leading to Extravascular (in spleen) hemolysis, and anemia (reduced levels of circulating RBCs), aplastic crisis •Splenomegaly

Helicobacter pylori THe discovery of H. pylori and its association with peptic ulcer disease, adenocarcinoma, gastric lymphoma, and other diseases make it one of the most significant medical discoveries of this century. In the United States, about 26 million people will su ffer from ulcer disease in their lifetime and up to 90% will likely be due to H. pylori. H. pylori is a gram-negative bacterium with high urease activity, an enzyme that catalyzes the formation of ammonia from urea. "e ammonia (NH3) is converted to ammonium (NH4) in the acid environment of the stomach. "e ammonium damages the gastric mucosal barrier because it damages epithelial cells. H. pylori also increases gastric acid secretion, possibly by increasing parietal cell mass. "is combination of increased acid secretion along with damage to the gastric mucosal barrier promotes the development of gastric ulcer. Bile salts can damage the gastric mucosal barrier, but they do not have a clinically significant e ffect on acid secretion. Epidermal growth factor, gastrin, and mucous strengthen the gastric mucosal barrier.

Damage to the gastric mucosal barrier is a forerunner of gastric ulcer. Which of the following can both damage the gastric mucosal barrier and stimulate gastric acid secretion? Select one: a. Mucous b. Bile salts c. Gastrin d. Helicobacter pylori e. Epidermal growth factor

Dead Space Equation

Dead space = Tidal volume x PaCO2-PeCO2/PaCO2 *arterial CO2 *expired CO2

77. A 60-year-old male presents to his primary care physician with the complaint of being easily tired, to the point of having shortness of breath and great Difficulty climbing a flight of stairs. The patient has a known cigarette smoking history, having smoked since his early 20s. He started with smoking one Pack per day, before eventually developing a 2-3 pack-per-day habit in his 30s. The physician determines the patient to have a resting oxygen saturation of 90% [N=95-100%] pulmonary testing is performed and the changes from Baseline shown in the table are noted. Which of the following is primarily responsible for these pulmonary changes?

Decreased diffusion of oxygen across the respiratory membrane

115. A 70-year-old man is brought to the emergency department because of blurred vision, dry mouth, dysarthria, and weakness in upper extremities that Began 6 hours after eating dinner at home. His meal included home-canned green beans. A few hours after arrival in the emergency department, he goes Into respiratory arrest and is placed on mechanical ventilation. Which of the following best describes the mechanism of his illness?

Decreased release of acetylcholine

96. A 49-year-old man undergoes radical neck dissection for a malignancy. All four parathyroid glands are removed. He has hypocalcemia postoperatively. Calcium concentration returns to the reference range with calcium and vitamin D supplementation. Which of the following best describes the results of loss Of parathyroid hormone on vitamin D metabolism?

Decreased renal conversion of 25-hydroxyvitamin D to 1,25 dihydroxycholecalciferol

111. Which of the following best explains why deoxygenated blood can carry more carbon dioxide for a given PCO2 than oxygenated blood?

Deoxyhemoglobin is a better buffer of hydrogen ions than oxyhemoglobin

the action potential duration increases

Depolarization opens K+ channels and increases K+ conductance to a value even higher than occurs at rest (outward K+ current) - the membrane is repolarized. If the K+ channels are blocked, how would that affect the action potential?

The action potential travels along the muscle fiber ➝ depolarizes the muscle membrane ➝ the sarcoplasmic reticulum to release calcium ions ➝ Ca++ combines with troponin C ➝ moves the tropomyosin ➝ The active sites of the actin are allowed to attract the myosin cross-bridge heads ➝ Cross-Bridge Cycling

Describe the Mechanism of muscle contraction

92. A healthy 24-year-old man is participating in a study of swallowing. The manometric pressure changes that occur while this man swallows are shown. Which of the following traces best represents muscle activity in the upper esophageal sphincter?

Diagram D

Anion Gap

Difference between the concentrations of serum cations and anions: determined by measuring the concentrations of sodium cations and chloride and bicarbonate anions.

Protein Achlorhydria means simply that the stomach fails to secrete hydrochloric acid; it is diagnosed when the pH of the gastric secretions fails to decrease below 4 after stimulation by pentagastrin. When acid is not secreted, pepsin also usually is not secreted; even when it is, the lack of acid prevents it from functioning because pepsin requires an acid medium for activity. "us, protein digestion is impaired.

Digestion of which of the following foodstuffs is impaired to the greatest extent in patients with achlorhydria? Select one: a. Carbohydrate b. Protein c. Fat

D → X A normal Starling curve of the heart, showing stroke volume as a function of end-diastolic volume, is depicted by the curve on which an X is marked. The Starling curve below the normal one will result from a decrease in contractility (e.g., with heart failure) or an increase in afterload. The Starling curve above the normal curve will result from an increase in contractility or a decrease in afterload. Digitalis is a positive inotropic agent that will cause a point on the lower curve to shift to up and to the left, such that there is an increased stroke volume at a lower preload.

Digitalis is administered to a patient in congestive heart failure. Which of the shifts in the Starling curves shown below are consistent with the changes in ventricular function before and after digitalis in a patient with heart failure? Select one: a. C → B b. X → C c. X → A d. D → X e. E → D

65. A 14-year-old girl with a 3-month history of asthma comes to the physician for a follow-up examination. Current medications include inhaled Corticosteroids. Her symptoms occur less than once weekly. The physician recommends that the patient add a new drug [drug X] that, when administered During an asthmacic episode, will immediately increase the FEV1 to greater than 80% of the FVC. which of the following best describes the mechanism of Action of drug X?

Dilation of pulmonary bronchioles

Acute respiratory distress syndrome (ARDS), Chronic obstructive pulmonary disease (COPD), Pneumonia, Pulmonary edema

Disorders of gas exchange

guillain - Barré syndrome, polio, amyotrophic lateral sclerosis (ALS), multiple sclerosis

Disorders of respiratory muscles

will not occur Because the stimulus was delivered during the absolute refractory period, no action potential occurs. The inactivation gates of the Na+ channel were closed by depolarization and remain closed until the membrane is repolarized. As long as the inactivation gates are closed, the Na+ channels cannot be opened to allow for another action potential.

During a nerve action potential, a stimulus is delivered as indicated by the arrow shown in the following figure. In response to the stimulus, a second action potential a. of normal magnitude will occur b. will occur, but will not have an overshoot c. of normal magnitude will occur, but will be delayed d. will not occur e. of smaller magnitude will occur

Graph C Conduction abnormalities can produce first-degree, second-degree, or third-degree heart block. In a second-degree heart block, a P wave is not always followed by a QRS complex as in trace C, where the second P wave is not followed by a QRS complex. In a first-degree heart block, trace D, the interval between the beginning of the P wave and the beginning of the QRS complex (the PR interval) is longer than normal (greater than 0.2 seconds). In a third- degree heart block, conduction between the atria and ventricles is completely blocked so the atrial beats (represented by the P waves) and the ventricular beats (represented by the QRS complex) are completely dissociated.

During a routine physical examination, a 32-year-old female is found to have second-degree heart block. Which of the following ECG recordings was obtained from the patient during her physical examination? Select one: a. B b. C c. D d. A e. E

A surge of luteinizing hormone is secreted from the pituitary Ovulation will not take place unless a surge of LH precedes it. Immediately prior to ovulation the num- ber of follicles is decreasing due to normal attrition of all but one follicle, and consequently estrogen synthe- sis by the ovary is decreasing. Progesterone synthesis is stimulated by the LH surge.

During the 12-hr period preceding ovulation, which of the following is true? Select one: a. the plasma concentration of estrogen is rising b. A surge of luteinizing hormone is secreted from the pituitary c. the surge occurs immediately after the formation of the corpus luteum d. the number of developing follicles is increasing e. the surge is followed immediately by a fall in the plasma concentration of progesterone

She has been receiving hormone replacement therapy with estrogen and progesterone since she completed menopause After menopause, the absence of feedback inhibi- tion by estrogen and progesterone results in extremely high rates of FSH secretion. Women taking estrogen as part of hormone replacement therapy for symptoms associated with postmenopausal conditions have sup- pressed levels of FSH owing to the inhibitory effect of estrogen.

During the first few years after menopause, folliclestimulating hormone (FSH) levels are normally extremely high. A 56-year-old woman completed menopause 3 years ago. However, she is found to have low levels of FSH in her blood. Which of the following is the best explanation for this finding? Select one: a. She took birth control pills for 20 years before menopause b. She has been receiving hormone replacement therapy with estrogen and progesterone since she completed menopause c. Her ovaries continue to secrete estrogen d. Her adrenal glands continue to produce estrogen

Liver Red blood cell production begins in the yolk sac for the first trimester. Production in the yolk sac decreases at the beginning of the second trimester and the liver becomes the predominate source of red cell production. During the third trimester red cell production increases from the bone marrow and con- tinues throughout life.

During the second trimester of pregnancy, where is the predominant site of red blood cell production? Select one: a. Lymph nodes b. Liver c. Yolk sac d. Bone marrow

there is net inward current and the cell interior becomes less negative During the upstroke of the action potential, the cell depolarizes, or becomes less negative. The depolarization is caused by inward current, which is, by definition, the movement of positive charge into the cell. In nerve and in most types of muscle, this inward current is carried by Na+.

During the upstroke of the nerve action potential a. there is net inward current and the cell interior becomes less negative b. there is net inward current and the cell interior becomes more negative c. there is net outward current and the cell interior becomes more negative d. there is net outward current and the cell interior becomes less negative

Isovolumetric ventricular relaxation The mitral [atrioventricular (AV)] valve opens when left atrial pressure becomes higher than left ventricular pressure. This situation occurs when the left ventricular pressure is at its lowest level—when the ventricle is relaxed, blood has been ejected from the previous cycle, and before refilling has occurred.

During which phase of the cardiac cycle does the mitral valve open? Select one: a. Isovolumetric ventricular contraction b. Atrial systole c. Isovolumetric ventricular relaxation d. Rapid ventricular filling e. Rapid ventricular ejection f. Reduced ventricular filling (diastasis) g. Reduced ventricular ejection

ventricular ejection Aortic pressure reaches its highest level immediately after the rapid ejection of blood during left ventricular systole. This highest level actually coincides with the beginning of the reduced ventricular ejection phase.

During which phase of the cardiac cycle is aortic pressure highest? Select one: a. ventricular ejection b. Rapid ventricular filling c. Atrial systole d. Isovolumetric ventricular contraction e. Isovolumetric ventricular relaxation

Isovolumetric ventricular relaxation Ventricular volume is at its lowest value while the ventricle is relaxed (diastole), just before ventricular filling begins.

During which phase of the cardiac cycle is ventricular volume lowest? Select one: a. Isovolumetric ventricular contraction b. Rapid ventricular filling c. Isovolumetric ventricular relaxation d. Rapid ventricular ejection e. Atrial systole f. Reduced ventricular ejection g. Reduced ventricular filling (diastasis) Feedback

22. Researchers are studying how the membrane potential of a postsynaptic neuron changes in response to neurotransmitter stimulation. Baseline measurements determine that the resting membrane potential is generated by high membrane permeability for a particular ion. When neurotransmitter stimulation begins, ligand-gated ion channels open (black arrow) and increase the membrane permeability for a different ion, causing a change in membrane potential. This triggers the delayed opening of voltage-gated ion channels (red arrow), which increase the membrane permeability for a third type of ion. The results of the experiment are shown in the graph below. The equilibrium potentials of different ions under physiologic conditions are as follows Ena= +60 mV EK= -90mV ECl= +75mV ECa= +125 mV Which of the following options would best explain the changes in this neurons membrane potential during the experiment?

E

Multiunit Smooth Muscle

Each muscle fiber behaves as a separate motor unit (similar to skeletal muscle)

4.0 It is a common misconception that the pH of the gastric contents is lowest (most acidic) following a meal when acid secretion is highest. Before a meal, when the stomach is empty, the pH of the gastric contents is the lowest and acid secretion is suppressed. Acid secretion is low because (a) the acid stimulates somatostatin release (which has a direct action to decrease secretion of both gastrin and acid), and (b) acid has a direct effect to suppress parietal cell secretions. When a meal is taken, the buffering effects of the food cause the gastric pH to increase, which allows the various secretagogues to stimulate acid secretion.

Eating a meal leads to a large increase in gastric acid secretion that peaks within about 5 min and returns to normal about 4 hr after a meal is taken. How long after a meal does the pH of the gastric contents reach its lowest level (in hours)? Select one: a. 4.0 b. 2.5 c. 2.0 d. 1.0 e. 1.5 f. 3.0

𝛑= g C 𝛔 R T

Effective osmotic pressure is the difference in

52. A 56-year-old man presents to the emergency department with fever, night sweats, and a productive cough. He immigrated from Mexico three years ago and has not had medical care in the United states. He reports no history of medical conditions and takes no medications. Vitals include blood pressure 158/84 mm Hg, pulse 96/mon, respiratory rate 20/min, adn oxygen saturation 95% on room air. He appears diaphoretic with mildly increased work of Breathing. Chest x-ray shows a cavitary lesion in the upper lobe of the right lung, and he is diagnosed with tuberculosis. Which of the following explains The location of this patient's lesion in the lungs?

Elevated V/Q ratio

Endurance training usually does not increase the mass of muscle but instead increases the number of blood vessels (for delivery of more oxygen and glucose) and mitochondria (for delivery of ATP) in the muscle

Endurance training increases the number of ?

25. A 52-year-old woman has menstrual irregularities, hot flashes, and emotional lability. In this patient, decreased follicular hormone production has most likely resulted in an increased serum concentration of which of the following substances?

Follicle-stimulating hormone

adrenergic

Excessive stimulation of receptors will lead to down regulation and a decrease in the concentration of the receptors on cell surface in what type of fibers?

43. A 54-year-old man comes to the physician for a routine health maintenance examination. His pulse is 80/min, respirations are 14/min, and blood pressure is 140/95 mm Hg. Physical examination shows no other abnormalities. An angiotensin 1-converting enzyme inhibitor is prescribed. Which of the following labeled regions in the illustration of the kidney shown will be most affected by the administration of this drug?

F

85. A 70-year-old man has an 18-month history of hypertension. His past health has been good and he takes no medications. Blood pressure is 165/110mm Hg. there are bruits in the neck and flank. Serum electrolyte concentrations are within the reference range, adn serum creatinine concentration is 2.5 mg/dL [N=0.6-1.2 mg/dL]. Urinalysis is negative for glucose, protein cells, and casts. Which of the following best reflects the plasma renin-angiotensin-Aldosterone profile in this patient?

F

Hemophilia B

Factor IX deficiency

A - surface area for exchange •↓ in emphysema •↑ in exercise •T - thickness of the membranes between alveolar gas and capillary blood, •↑ in fibrosis and many other restrictive diseases •D (diffusion constant) - main factor is solubility •The more soluble the gas, the faster it diffuses across the membranes. •CO2 is the most soluble gas. •diffuses faster across the alveolar membranes than O2. •(P1 - P2) - Gradient across the membrane •The greater the partial pressure difference, the greater the rate of diffusion •the gradient for CO2 is less than for O2 •An increase in the PO2 gradient across the lung membranes helps compensate for a structural problem. •Diffusing Capacity Of The Lung - CO

Factors That Affect the Rate of Diffusion:

94. A 35-year-old weight lifter, who has been injecting testosterone for muscle mass augmentation, is evaluated for sterility and found to have an extremely Low sperm count. Which of the following is an effect of testosterone and contributes to the mentioned sterility?

Feedback inhibition of GnRH

Fetal erythropoiesis

Fetal erythropoiesis occurs in: •Yolk sac (3-8 weeks of gestation) •Liver (6 weeks of gestation-birth) •Spleen (10-28 weeks of gestation) •Bone marrow (18 weeks of gestation to adult) mnemonic Young Liver Synthesizes Blood

Opening of voltage-gated Na+ channels: depolarization

For a summer research project, a second-year medical student is introduced to the patch clamp technique in a neurophysiology laboratory. As part of her training, she learns to monitor both membrane potential and individual channel function. At the end for the summer, she is able to write up the specific techniques and findings from monitoring action potentials. Which of the following ionic changes is correctly matched with a component of the action potential? Select one: a. Rapid closure of voltage-gated Na+ channels: resting membrane potential b. Rapid closure of voltage-gated K+ channels: relative refractory period c. Opening of voltage-gated Na+ channels: depolarization d. Opening of voltage-gated K+ channels: after-hyperpolarization e. A decrease in extracellular Ca2+: repolarization

β-Receptor antagonists work by inhibiting β-receptors, hindering the G-protein/cyclic adenosine monophosphate (cAMP) mechanism. By reducing the amount of cAMP and protein kinase A (PKA) produced, β-receptor antagonists decrease the Na+ and Ca2+ currents within the AV node. (Decreased production of cAMP and PKA reduces the Na+ current via phosphorylation-mediated downregulation of expression and other mechanisms). Thus β-receptor antagonists decrease the slope of phase 4 and phase 0. As a result, abnormal pacemakers can be suppressed. β-Receptor antagonists are known to slow the heart rate (negative chronotropic effect). β-Receptors do not utilize the inositol triphosphate mechanism and thus are not involved with protein kinase C. β-Receptor antagonists cause a decrease in cyclic adenosine monophosphate. β-Receptor antagonists cause a decrease in protein kinase A

Functions of β-receptor antagonists

Decreased ability to concentrate the urine Furosemide (Lasix) inhibits the Na -2Cl -K co-transporter in the ascending limb of the loop of Henle. is not only causes marked natriuresis and diuresis but also reduces the urine concentrating ability. Furosemide does not cause edema; in fact, it is often used to treat severe edema and heart failure. Furosemide also increases the renal excretion of potas- sium and calcium and therefore tends to cause hypo- kalemia and hypocalcemia rather than increasing the plasma concentrations of potassium and calcium.

Furosemide (Lasix) is a diuretic that also produces natriuresis. Which of the following is an undesirable side effect of furosemide due to its site of action on the renal tubule? Select one: a. Heart failure b. Decreased ability to concentrate the urine c. Hyperkalemia d. Hypercalcemia e. Edema

C Gastrin, acetylcholine, and histamine can directly stimulate parietal cells to secrete acid. "ese three secretagogues also have a multiplicative effect on acid secretion such that inhibition of one secretagogue reduces the effectiveness of the remaining two secretagogues. Acetylcholine also has an indirect effect to increase acid secretion by stimulating gastrin secretion from G cells. Somatostatin inhibits acid secretion.

Gastric acid is secreted when a meal is consumed. Which of the following factors have a direct action on the parietal cell to stimulate acid secretion? Select one: a. A b. B c. D d. E e. C

Antral peristalsis Antral peristalsis pushes chyme toward the pylorus and thus promotes gastric emptying. Other factors that promote gastric emptying include (a) decreased compliance of the stomach, (b) relaxation of the pylorus, and (c) an absence of segmentation contractions in the small bowel. Gastric emptying is thought to be slow in eating disorders such as anorexia nervosa, bulimia nervosa, and obesity. Scleroderma is a systemic disease that aff ects many organ systems. " e symptoms result from progressive tissue fibrosis and occlusion of the microvasculature by excessive production and deposition of types I and III collagens. Deposition of fibrous tissues in the pylorus reduces gastric emptying. Gastroparesis (paralysis of the stomach) occurs in about 20% of type I diabetics. " e high blood glucose is thought to damage the vagus nerve and thereby reduce gastric emptying.

Gastric emptying is regulated to ensure the chyme enters the duodenum at an appropriate rate. Which of the following factors promotes gastric emptying? Select one: a. Scleroderma b. Anorexia nervosa c. Obesity d. Bulimia nervosa e. Type I diabetes f. Antral peristalsis

C Gastric emptying is accomplished by coordinated activities of the stomach, pylorus, and small intestine. Conditions that favor gastric emptying include (a) increased tone of the orad stomach because this helps to push chyme toward the pylorus, (b) forceful peristaltic contractions in the stomach that move chyme toward the pylorus, (c) relaxation of the pylorus which allows chyme to pass into the duodenum, and (d) absence of segmentation contractions in the intestine, which can otherwise impede the entry of chyme into the intestine.

Gastric emptying is tightly regulated to ensure that chyme enters the duodenum at an appropriate rate. Which of the following events promotes gastric emptying under normal physiological conditions in a healthy person? Select one: a. A b. B c. C d. E e. D

Pyloric stenosis The emptying of solids from the stomach is determined by the strength of antral peristaltic contractions and the resistance offered by the pyloric sphincter. Either a decrease in the amplitude of the antral contractions or an increase in sphincter resistance will delay the emptying of solids from the stomach. Liquid emptying is regulated by the proximal stomach and is primarily a function of the differ- ence between the intragastric pressure and the intraduodenal pressure.

Gastric emptying studies performed on a 49-year-old female reveal a time to one-half emptying of liquids of 18 min (normal < 20 min) and a time to one-half emptying of solids to be 150 min (normal < 120 min). Which of the following best explains the data? Select one: a. Inflammation of the proximal small intestine b. Sectioning of the vagus nerves to the stomach c. Increased amplitude of antral contractions d. Decreased orad stomach compliance e. Pyloric stenosis

0.15 Filtration fraction is calculated as the GFR divided by the renal plasma flow. GFR is equal to the net filtration pressure (glomerular hydrostatic pres- sure minus Bowman's hydrostatic pressure minus colloid osmotic pressure in glomerular capillaries) multiplied by the capillary filtration coefficient. us, the filtration fraction is equal to the GFR (60 ml/min) divided by the renal plasma flow (400 ml/min), or 0.15.

Given the following measurements, calculate the filtration fraction : glomerular capillary hydrostatic pressure = 50 mm Hg; Bowman's space hydrostatic pressure = 15 mm Hg; colloid osmotic pressure in the glomerular capillaries = 30 mm Hg; glomerular capillary filtration coeffi cient (Kf ) = 12 ml/min/mm Hg; and renal plasma flow = 400 ml/min. Select one: a. 0.35 b. 0.30 c. 0.25 d. 0.15 e. 0.20

PGE2 strongly stimulates uterine contraction the fetal portion of the placenta releases prosta- glandins in high concentrations at the time of labor. is release is associated with deterioration of the pla- centa. Prostaglandins, especially PGE2, strongly stimu- late uterine smooth muscle.

Giving prostaglandin E2 (PGE2 ) to a pregnant woman may result in an abortion. What is the best explanation for this finding? Select one: a. PGE2 increases the secretion of progesterone from the corpus luteum b. PGE2 strongly stimulates uterine contraction c. PGE2 causes constriction of the arteries leading to the placenta d. PGE2 stimulates the release of oxytocin from the posterior pituitary

Acute hyperglycemia Under acute conditions, an increase in blood glucose concentration will decrease growth hor- mone secretion. Growth hormone secretion is char- acteristically elevated in the chronic pathophysio- logical states of Acromegaly and Gigantism. Deep sleep and exercise are stimuli that increase growth hormone secretion.

Growth hormone secretion would most likely be suppressed under which of the following conditions? Select one: a. Gigantism b. Deep Sleep c. Acute hyperglycemia d. Acromegaly e. Exercise

A Histamine is a vasodilator that is typically released by mast cells and basophils. Infusion of histamine into a brachial artery would decrease arteriolar resistance and increase water permeability of the capillary wall. e decrease in arteriolar resistance would also increase capillary hydrostatic pressure. e increase in capillary hydrostatic pressure and water permeability leads to an increase in capillary filtration rate.

Histamine is infused into the brachial artery. Which of the following sets of microcirculatory changes would be expected in the infused arm? Select one: a. B b. A c. E d. F e. D f. H g. G h. C

heart rate = 300/N of large squares

How can you measure heart rate on ECG graph paper?

93. A 40-year-old woman complains of chronic fatigue, aching muscles, and general weakness. Physical examination reveals a modest weight gain, dry skin, and slow reflexes. Laboratory findings include TSH: >10 mU/L [normal range 0.5-5 mU/L], free T4: low. Which of the following is the most likely explanation?

Hypothyroidism due to autoimmune thyroid disease

SIADH Drinking significant quantities of water 0.45% NaCl infusion

ICF and ECF volume expands, osmolarity decreases

secretory diarrhea, vomiting

ICF no change, Osmolarity no change, ECF volume expands

High-NaCl intake Hypertonic infusion of solutes

ICF volume decreases, ECF volume expands, Osmolarity increases

Sweating, diabetes insipidus

ICF volume decreases, osmolarity increases, ECF decreases

0.06 mEq/min K excretion rate = urine K+ concentration (60 mEq/L) x urine flow rate (0.001 L/min) = 0.06 mEq/min

If a patient has a creatinine clearance of 90 ml/min, a urine flow rate of 1 ml/min, a plasma K# concentration of 4 mEq/L, and a urine K# concentration of 60 mEq/L, what is the approximate rate of K# excretion? Select one: a. 0.06 mEq/min b. 0.36 mEq/min c. 60 mEq/min d. 3.6 mEq/min e. 0.30 mEq/min

150 mg/min In this example, the filtered load of glucose is equal to GFR (100 ml/min) plasma glucose (150 mg/dL), or 150 mg/min. If there is no detectable glucose in the urine, the reabsorption rate is equal to the filtered load of glucose, or 150 mg/min.

If a person has a kidney transport maximum for glucose of 350 mg/min, a GFR of 100 ml/min, a plasma glucose of 150 mg/dL, a urine flow rate of 2 ml/min, and no detectable glucose in the urine, what would be the approximate rate of glucose reabsorption, assuming normal kidneys? Select one: a. 50 mg/min b. 350 mg/min c. 0 mg/min d. Glucose reabsorption cannot be estimated from these data e. 150 mg/min

8 mm Hg The net filtration pressure at the glomerular capil- laries is equal to the sum of the forces favoring filtra- tion (glomerular capillary hydrostatic pressure) minus the forces that oppose filtration (hydrostatic pressure in Bowman's space and glomerular colloid osmotic pressure). Therefore, the net pressure driving glomer- ularfiltrationis 50 - 12 - 30 = 8mmHg.

If the average hydrostatic pressure in the glomerular capillaries is 50 mm Hg, the hydrostatic pressure in the Bowman's space is 12 mm Hg, the average colloid osmotic pressure in the glomerular capillaries is 30 mm Hg, and there is no protein in the glomerular ultrafiltrate, what is the net pressure driving glomerular filtration? Select one: a. 32 mm Hg b. 60 mm Hg c. 92 mm Hg d. 48 mm Hg e. 8 mm Hg

The potassium conductance will increase Increasing the extracellular concentration of K+ causes the cell to depolarize, that is, to become more positive. When the cell depolarizes, the activation gate on the K+ channel opens, causing K+ conductance to rise. Depolarization causes both the opening of the Na+ activation (m) gate and the closing of the Na+ inactivation(h) gate. As a result, Na+ conductance remains the same. The inactivation of the Na+ channels resulting from depolarization reduces membrane excitability. The activity of the Na-K pump will decrease if extracellular K+concentration is decreased.

If the extracellular K+ concentration is increased from 4 meq/L to 10 meq/L, Select one: a. The potassium conductance will increase b. The membrane potential will become more negative c. The Na-K pump will become inactivated d. The membrane will become more excitable e. The sodium conductance will increase

3 Net diffusion of a substance across a permeable membrane is proportional to the concentration difference of the substance on either side of the membrane. Initially, the concentration difference is 5 millimolar(10 millimolar - 5 millimolar). When the intracellular concentration doubles to 20 millimolar, the concentrationdifference becomes 15 millimolar (20 millimolar - 5 millimolar). !e concentration difference has tripled; therefore, the rate of diffusion would also increase by a factor of 3.

If the intracellular concentration of a membranepermeant substance doubles from 10 to 20 millimolar and the extracellular concentration remains at 5 millimolar, the rate of diffusion of that substance across the plasma membrane will increase by a factor of how much? Select one: a. 6 b. 2 c. 4 d. 5 e. 3

hypotonic

If the solution causes hemolysis what is the tonicity?

hypertonic

If the solution causes the cell to shrink what is the tonicity?

Active hyperemia

Illustrates the concept that blood flow to an organ is proportional to its metabolic activity

-90 mV

In a patch clamp experiment on a neuron, a student is able to accurately measure membrane potential. At the start of the measurements, the student finds that the resting membrane potential is normal for a neuron, measuring -70 mV. The student manipulates the preparation to allow for membrane potential to stabilize at the K+ equilibrium (EK). In this preparation, the intracellular concentration for K+ is 150 mmol/L and the extracellular concentration for K+ is 5.5 mmol/L. Assuming the temperature of the experiment is 37°C, what is the equilibrium potential of the neuron in the experiment? Select one: a. +70 mV b. +90 mV c. -70 mV d. -44 mV e. -90 mV f. +44mV

Activation of cyclic AMP or cyclic GMP G-proteins binding can lead to the activation of cyclic AMP or cyclic GMP. Such proteins do not close sodium or potassium channels nor do they inactivate various enzymes, gene transcription, or transmitter agents

In chemical synapses that involve a so-called second messenger, typically a G-protein linked to the postsynaptic receptor is activated when neurotransmitter binds to that receptor. Which of the following represents an activity performed by the activated second messenger? Select one: a. Inactivation of gene transcription in the postsynaptic neuron b. Inactivation of enzymes that initiate biochemical reactions in the postsynaptic neuron c. Closure of a membrane channel for sodium or potassium d. Activation of cyclic AMP or cyclic GMP

Usually hypotonic compared with plasma As water flows up the ascending limb of the loop of Henle, solutes are reabsorbed, but this segment is relatively impermeable to water; progressive dilution of the tubular fluid occurs so that the osmolarity decreases to approximately 100 mOsm/L by the time the fluid reaches the early distal tubule. Even during maximal antidiuresis, this portion of the renal tubule is relatively impermeable to water and is therefore called the diluting segment of the renal tubule.

In normal kidneys, which of the following is true of the osmolarity of renal tubular fluid that flows through the early distal tubule in the region of the macula densa? Select one: a. Hypertonic, compared with plasma, in antidiuresis b. Usually hypertonic compared with plasma c. Usually hypotonic compared with plasma d. Usually isotonic compared with plasma

E It is remarkable that the arterial PO2, PCO2, and pH remain almost exactly normal in a healthy athlete dur- ing strenuous exercise despite the 20-fold increase in oxygen consumption and carbon dioxide formation. is interesting phenomenon begs the question: What is it during exercise that causes the intense ventilation?

In strenuous exercise, oxygen consumption and carbon dioxide formation can increase as much as 20-fold. Alveolar ventilation increases almost exactly in step with the increase in oxygen consumption. Which of the following best describes what happens to the mean arterial oxygen tension (PO%), carbon dioxide tension (PCO%) and pH in a healthy athlete during strenuous exercise? Select one: a. A b. B c. C d. D e. E

A

In the Wiggers diagram below, at which point will sarcomere length of left ventricular myocytes be greatest? Select one: a. E b. D c. A d. C e. B

b. The redistribution of fluid volume shown in diagram B reflects the net di ffusion of water, or osmosis, due to di fferences in the osmolarity of the solutions on either side of the semipermeable membrane. Osmosis occursfrom solutions of high water concentration to low water concentration or from low osmolarity to high osmolarity. In diagram B, osmosis has occurred from X to Y and from Y to Z. !erefore, the osmolarity of solution Z is higher than that of solution Y, and the osmolarity of solution Y is higher than that of solution X.

In the experiment illustrated in diagram A, equal volumes of solutions X, Y, and Z are placed into the compartments of the two U-shaped vessels shown. The two compartments of each vessel are separated by semipermeable membranes (i.e., impermeable to ions and large polar molecules). Diagram B illustrates the fluid distribution across the membranes at equilibration. Assuming complete dissociation, identify each of the solutions shown. Select one: a. b b. a c. c d. d e. e

B and C n acromegaly, high plasma levels of growth hor- mone cause insulin resistance. Consequently, there is increased glucose production by the liver and im- paired glucose uptake by peripheral tissues.

In the figure, which lines most likely illustrate these relationships in a patient with acromegaly? Select one: a. A and D b. B and C c. A and C d. B and D

A and D In patients with nephrogenic diabetes insipidus, the kidneys do not respond appropriately to antidi- uretic hormone (ADH), and the ability to form con- centrated urine is impaired. In contrast, there is a normal ADH secretory response to changes in plasma osmolality.

In the following figure, which lines most likely reflect the responses in a patient with nephrogenic diabetes insipidus? Select one: a. A and D b. B and D c. A and C d. B and C

c. The membrane potential of a cell is dictated by the equilibrium potentials (Nernst potentials) and relative permeabilities (conductances) of the various ions in which the cell lives. When the permeability to an ion is increased, the membrane potential will approach the equilibrium potential of the ion. Equal increases (or decreases) in the membrane conductances for Q and S ions will thus have no effect on membrane potential because the equilibrium potentials of these ions are distributed equidistant above (ion Q) and below (ion S) the resting membrane potential of the cell.

In the graph shown below, Pmemb represents the initial membrane potential for a hypothetical cell. In relation to this membrane potential, the equilibrium potentials of three ions (Q, R, S) are represented. Which of the following paths is most likely taken by the membrane potential when membrane conductances to Q and S ions are increased simultaneously by a thousand fold? Select one: a. e b. d c. c d. b e. a

point D The graph illustrates the development of pressure in the aorta, the left atrium, and the left ventricle during a single cardiac cycle. At point D, the pressure within the left ven- tricle is less than the pressure in the left atrium, and, therefore, the mitral valve opens and ventricular filling begins. Although the volume in the left ventricle is increasing, the pressure is falling. During this time period, the recoil of the ventricle causes its pressure to decrease as it is filling. Later in diastole, the pressure of the blood returning from the lungs causes both volume and pressure in the ventricle to increase.

In the hemodynamic pressure tracings below, rapid ventricular filling begins at which point on the figure below? Select one: a. B b. C c. A d. E e. D

Increased alveolar ventilation and unchanged metabolism Alveolar PO2 is dependent on inspired gas and alveolar PCO2. Alveolar PCO2 is a balance between al- veolar ventilation and CO2 production. To decrease alveolar PCO2 there has to be increased alveolar venti- lation in relation to metabolism. Low PO2 will not di- rectly affect PCO2, but can stimulate respiration (if PO2 is sufficiently low) and this would then reduce PCO2). An increased metabolism with unchanged alveolar ventilation will increase PCO2. A doubling in metabo- lism with a doubling in alveolar ventilation will have no effect on PCO2

In which of the following conditions is alveolar PO% increased and alveolar PCO% decreased? Select one: a. Increased metabolism and unchanged alveolar ventilation b. Decreased alveolar ventilation and unchanged metabolism c. Proportional increase in metabolism and alveolar ventilation d. Increased alveolar ventilation and unchanged metabolism

Spinal cord injury Sympathomimetic drugs are given to counteract hypotension during a number of conditions. ese include spinal cord injury in which the sympathetic output is interrupted. Sympathomimetic drugs are also given during very deep anesthesia which decreases the sympathetic output, and in anaphylac- tic shock that results from histamine release and the accompanying vasodilatation. Sympathomimetic drugs, such as norepinephrine, increase blood pres- sure by causing a vasoconstriction. Shock caused by excess vomiting, hemorrhage or excessive adminis- tration of diuretics result in fluid volume depletion resulting in decreased blood volume and decreased mean systemic filling pressure. Giving a balanced electrolyte solution best counteracts this condition

In which of the following conditions will administration of a sympathomimetic drug be the therapy of choice to prevent shock? Select one: a. Spinal cord injury b. Hemorrhagic shock c. Shock caused by excess diuretics d. Shock due to excessive vomiting

Left-to-right ventricular shunt In a left-to-right ventricular shunt, a defect in the ventricular septum allows blood to flow from the left ventricle to the right ventricle instead of being ejected into the aorta. The "shunted" fraction of the left ventricular output is therefore added to the output of the right ventricle, making pulmonary blood flow (the cardiac BRS output of the right ventricle) higher than systemic blood flow (the cardiac output of the left ventricle). In normal adults, the outputs of both ventricles are equal in the steady state. In the fetus, pulmonary blood flow is near zero. Right ventricular failure results in decreased pulmonary blood flow. Administration of a positive inotropic agent should have the same effect on contractility and cardiac output in both ventricles.

In which of the following situations is pulmonary blood flow greater than aortic blood flow? Select one: a. Administration of a positive inotropic agent b. Right-to-left ventricular shunt c. Right ventricular failure d. Fetus e. Normal adult f. Left-to-right ventricular shunt

Septic shock In hemorrhagic shock, anaphylactic shock and neurogenic shock the venous return of blood to the heart markedly decreases. However, in septic shock the cardiac output increases in many patients because of vasodilation in affected tissues and by a high metabolic rate causing vasodilation in other parts of the body.

In which type of shock does cardiac output often increase? Select one: a. Septic shock b. Hemorrhagic shock c. Neurogenic shock d. Anaphylactic shock

35. A 50-year-old man comes to the physician for a routine examination. There are no orthostatic changes in pulse or blood pressure. Physical examination shows no abnormalities. Laboratory studies show a hemoglobin concentration of 12 g/dL (N=13.5-17.5 g/dL) and hematocrit 36% (N=41-53%). Six months ago, his hemoglobin concentration was 15 g/dL and was 46%. Test of the stool for occult blood is positive. The physician concludes that an increased delivery of oxygen to the tissues has prevented the emergence of symptoms of anemia. Which of the following events most likely increased the oxygen delivery in this patient?

Increase in erythrocyte 2,3-biphosphoglycerate concentration

106. A 50-year-old man comes to the physician because of severe chest pain for the past several months. Pulse is 74/min, and blood pressure is 160/98 mm Hg. Further evaluation showed aortic stenosis. Coronary blood flow is greater than normal. Which of the following contributes to the increased coronary Blood flow in this patient?

Increased adenosine concentration in cardiac tissue

75. An investigator is conducting a study on hematological factors that affect the affinity of hemoglobin for oxygen. An illustration of two graphs [A and B] that Represent the affinity of hemoglobin for oxygen is shown. Which of the following best explains a shift from A to B?

Increased body temperature

100. A 48-year-old woman comes to the emergency department because of palpitations. Pulse is 180/min, and blood pressure is 104/68 mm Hg. ECG shows An atrioventricular [AV] nodal reentrant tachycardia. Carotid sinus rhythm is restored. Which of the following is the Likely mechanism of the termination of the tachycardia in this patient?

Increased cardiac parasympathetic activity

82. The graph in the figure below shows the pressure-volume curve of the left ventricle of this patient [shaded area]. The pressure-volume curve of a normal Subject is shown for comparison [broken lines]. Compared to normal, which term best describes this patient's heart?

Increased force of contraction

41. A 67-year-old man with severe congestive heart failure and edema has gained 9.1 kg (20 lb). Which of the following is most likely to renal sodium retention?

Increased renal sympathetic nerve activity

Furosemide

Inhibits Na+/K+/2Cl− prevents concentration of urine ↓ Ca++ reabsorption, ↑ Ca++ excretion hypokalemia

Hydrochlorothiazide

Inhibits NaCl reabsorption in early DCT ↓ diluting capacity of nephron ↑ Ca++ reabsorption, ↓ Ca++ excretion hypokalemia

76. A 45-year-old man has a malignant tumor of the pancreas. Immunohistochemical stain reveals the tumor arises from delta cells. Which of the following Best describes the hormone these malignant cells are secreting?

Inhibits insulin and glucagon secretion

the aortic valve closes before the pulmonic valve The second heart sound is associated with closure of the aortic and pulmonic valves. Because the aortic valve closes before the pulmonic valve, the sound can be split by inspiration.

Inspiration "splits" the second heart sound because Select one: a. the mitral valve closes before the tricuspid valve b. filling of the ventricles has fast and slow components c. the tricuspid valve closes before the mitral valve d. the pulmonic valve closes before the aortic valve e. the aortic valve closes before the pulmonic valve

12. A healthy person is given intravenous doses of inulin and 125I-labeled albumin. The inulin space is calculated as 15L, and 125I-albumin space as 3L. What body fluid compartment can be calculated using this data?

Interstitial fluid volume

- 77 mV

Intracellular potassium concentration is held constant at 180 mEq/L. The plasma potassium concentration is changed from 5,3 to 9.5 mEq/L Which of the following the equilibrium membrane potentials seen after this change? Select one: a. -77 mV b. +100 mV c. +103 mV d. -56 mV e. -104 mV

B Infusion of a hypotonic solution of NaCl would initially increase extracellular fluid volume and decrease extracellular fluid osmolarity. The reduction in extracellular fluid osmolarity would cause osmotic flow of fluid into the cells, thereby increasing intracel- lular fluid volume and decreasing intracellular fluid osmolarity after osmotic equilibrium.

Intravenous infusion of 1 L of 0.45% sodium chloride (NaCl) solution (molecular weight of NaCl = 58.5) would cause which of the following changes, after osmotic equilibrium? Select one: a. A b. B c. C d. D e. E

97. The patient is a 43-year-old male. He is anemic, with a hemoglobin level of 12.2 g/dL [normal is 15.5 g/dL]. The erythrocytes are microcytic [MCV = 70 fL, With normal MCV = 80-100 fL]. Which of the following would most likely be present in this patient?

Iron deficiency

117. Figure below illustrates uptake of two gasses [nitrous oxide and carbon monoxide] from alveolar air to pulmonary capillary blood. Based on this information what can we conclude about carbon monoxide?

It is a diffusion limited gas

105. Which of the following is the role of iodine in the biosynthesis of thyroxine [T4]?

It is added to tyrosine residues in thyroglobulin in the first step of T4 biosynthesis

86. A 28-year-old, 166cm [5.45 ft] tall woman, weighting 170kg [375 lbs] successfully underwent biliopancreatic diversion surgery, in which a portion of her Stomach was removed and the remaining portion of the stomach was connected to the lower portion of the small intestine [see figure below]. What is her Prevalence for peptic ulcer ideas and for what reason?

It is lower since G cells were surgically resected

17. The graphs depict the relationship between cardiac output and heart rate, end diastolic volume, and stroke volume for healthy elderly men and healthy younger men. Based on the results of these studies, which of the following age-related anatomic changes contributes to well-maintained cardiac output in the elderly men?

Left ventricular dilation

Vitamin B12 deficiency

Macrocytic anemia: MCV > 100 fL, ↓ RBC count & Htc , Macrocitosis (Megaloblastic RBC), pernicious anemia, gastrectomy, , veganism, Diphyllobothrium latum, Neurologic symptoms)

Prolonged opening of the ryanodine receptor channel As long as the ryanodine receptor channel on the sarcoplasmic reticulum remains open, Ca++ will continueto flood the sarcoplasm and stimulate contraction. This prolonged contraction results in heat production,muscle rigidity, and lactic acidosis. In contrast, factors that either inhibit Ca++ release or stimulate Ca++ uptake into the sarcoplasmic reticulum, or that prevent either the depolarization of the T tubulemembrane or the transduction of the depolarization into Ca++ release, would favor muscle relaxation.

Malignant hyperthermia is a potentially fatal genetic disorder characterized by a hyper-responsiveness to inhaled anesthetics and results in elevated body temperature, skeletal muscle rigidity, and lactic acidosis. Which of the following molecular changes could account for these clinical manifestations? Select one: a. Decreased voltage sensitivity of the dihydropyridine receptor b. Enhanced activity of the sarcoplasmic reticulum Ca++-ATPase c. Reduction in the density of voltage-sensitive Na! channels in the T tubule membrane d. Prolonged opening of the ryanodine receptor channel

Bowel movements Mass movements force feces into the rectum. When the walls of the rectum are stretched by the feces, the defecation reflex is initiated and a bowel movement follows when this is convenient. Mass movements do not aff ect gastric motility. Haustrations are bulges in the large intestine caused by contraction of adjacent circular and longitudinal smooth muscle. It should be clear that mass movements in the colon do not aff ect esophageal contractions or pharyngeal peristalsis.

Mass movements are often stimulated after a meal by distention of the stomach (gastrocolic reflex) and distention of the duodenum (duodenocolic reflex). Mass movements often lead to which of the following? Select one: a. Haustrations b. Pharyngeal peristalsis c. Bowel movements d. Esophageal contractions e. Gastric movements

iron deficiency

Microcytic anemia: MCV < 80 fL, ↓ RBC count & Htc , ↓ iron, ↓ ferritin, fatigue, conjunctival pallor, pica, spoon nails - koilonychia

Intestinal bacteria Migrating motility complexes (sometimes called interdigestive myoelectric complexes) are peristaltic waves of contraction that begin in the stomach and slowly migrate in an aboral direction along the entire small intestine to the colon. By sweeping undigested food residue from the stomach, through the small intestine, and into the colon, MMCs function to maintain low bacterial counts in the upper intestine. Bacterial overgrowth syndrome can occur when the normally low bacterial colonization in the upper gastrointestinal tract increases significantly. It should be clear that an absence of MMCs would decrease duodenal motility and gastric emptying. MMCs do not have a direct effect on mass movements and swallowing.

Migrating motility complexes (MMC) occur about every 90 min between meals and are thought to be stimulated by the gastrointestinal hormone, motilin. An absence of MMCs causes an increase in which of the following? Select one: a. Gastric emptying b. Swallowing c. Mass movements d. Duodenal motility e. Intestinal bacteria

Examples of second messenger molecules include cyclic AMP, cyclic GMP, inositol triphosphate, diacylglycerol, and calcium. they can be opened or closed in response to various intracellular signals.

Name some examples of Second messenger-gated channels

Acetylcholine the nasal, lacrimal, salivary and gastrointestinal glands are stimulated by cholinergic postganglionic parasympathetic neurons.

Nasal, lacrimal, salivary, and gastrointestinal glands are stimulated by which of the following substances? Select one: a. Serotonin b. Epinephrine c. Dopamine d. Acetylcholine e. Norepinephrine

Ligand-gated channels

Nicotinic receptor for acetylcholine (ACh) at the motor end plate is what type of channel?

Aplastic anemia

Normocytic (MCV = 80-100fL) suppression or destruction of the bone marrow , ↓ RBC count & Htc , ↓ reticulocyte count, ↑ EPO, leukopenia, and thrombocytopenia, Bone marrow with fatty infiltration

hemolytic anemia

Normocytic (MCV = 80-100fL) ↓ RBC count & Htc, increases in LDH, ↑ reticulocytes, ↑ unconjugated bilirubin, ↑ urobilinogen in urine

ECF volume is 10 L Mannitol is a marker substance for the extracellular fluid (ECF) volume. ECF volume = amount of mannitol/concentration of mannitol = 1 g - 0.2 g/0.08 g/L = 10 L.

One gram of mannitol was injected into a woman. After equilibration, a plasma sample had a mannitol concentration of 0.08 g/L. During the equilibration period, 20% of the injected mannitol was excreted in the urine. The subject's Select one: a. ICF volume is 10 L b. interstitial volume is 12.5 L c. ECF volume is 10 L d. extracellular fluid (ECF) volume is 1 L e. intracellular fluid (ICF) volume is 1 L

E One of the most critical actions of gastrointestinal hormones is their trophic activity. Gastrin can stimulate mucosal growth throughout the gastrointestinal tract as well as growth of the exocrine pancreas. If most of the endogenous gastrin is removed by antrectomy, the gastrointestinal tract atrophies. Exogenous gastrin prevents the atrophy. Partial resection of the small intestine for tumor removal, morbid obesity, or other reasons results in hypertrophy of the remaining mucosa. "e mechanism for this adaptive response is poorly understood. Both cholecystokinin and secretin stimulate growth of the exocrine pancreas. GLIP (glucose-dependent insulinotropic peptide) and motilin do not appear to have trophic actions on the gastrointestinal tract.

One of the following hormones can stimulate growth of the intestinal mucosa and two other hormones can stimulate pancreatic growth. Which three hormones are these? Select one: a. B b. D c. C d. A e. E

Iron deficiency anemia this patient is anemic and has low hemoglobin with small red cells. Vitamin B12 and folic acid defi- ciency will result in macrocytic red blood cells. His WBC and platelet counts are normal, suggesting a normal bone marrow. e positive stool shows a gas- trointestinal blood loss. A person can be anemic from a blood loss and have normal-sized RBCs as long as there is enough iron in the body. e microcytic and hypochromic RBCs are classic signs of iron deficient anemia.

Over the past 12 weeks, a 75-year-old man with a moderate aortic stenosis has developed shortness of breath and chest pains during exertion. He appears pale. Test of his stool for blood is positive. Laboratory studies show the following: hemoglobin 7.2 g/dL, and mean corpuscular volume 75. A blood smear shows microcytic, hypochromic erythrocytes. Which of the following is the most likely diagnosis? Select one: a. Autoimmune hemolytic anemia b. Folate deficiency anemia c. Iron deficiency anemia d. Vitamin B12 deficiency

108. A 37-year-old man comes to the physician because of progressive heartburn over the past 6 months. The symptoms are most severe after eating large or Spicy meals and are partially relieved with antacid therapy. An endoscopic biopsy specimen of the lower esophagus shows esophagitis. The most likely Cause of the esophageal changes is a substance secreted by which of the following cell types?

Parietal cells

Tricuspid regurgitation Early systolic murmurs begin with the first heart sound and end in mid- systole. The higher-than-normal height of the jugular blood column reflects an increased right atrial pressure. The combination of an early systolic mur- mur and high right atrial pressure is indicative of tricuspid regurgitation. This lesion is common in narcotic abusers with infective endocarditis. Mitral stenosis and aortic regurgitation produce diastolic murmurs.

Physical examination of a 41-year-old narcotic abusor reveals an early systolic murmur. The physician also notes a 7-cm distance between the height of the blood in his right internal jugular vein and sternal angle (normal = 3 cm). Which of the following conditions is most likely responsible for the physical findings? Select one: a. Tachycardia b. Tricuspid regurgitation c. Aortic regurgitation d. Atherosclerosis e. Mitral stenosis

109. Following an operation, a 65-year-old patient has a lung region that is under-ventilated but well perfused. This condition will lead to an increase in which of the following?

Physiologic shunt

Troponin I and Troponin T

Preferred and most specific markers for cardiac injury because they are part of the cardiac cells contractile apparatus and should only be present in the blood when there is damage to the heart muscle itself

72. A 27-year-old woman has a suprasellar craniopharyngioma, which leads to pressure-induced atrophy of the posterior pituitary. Which of the following Responses is most likely in the kidney?

Production of a hypotonic urine

determined by stroke volume Pulse pressure is the difference between the highest (systolic) and lowest (diastolic) arterial pressures. It reflects the volume ejected by the left ventricle (stroke volume). Pulse pressure increases when the capacitance of the arteries decreases, such as with aging.

Pulse pressure is Select one: a. the highest pressure measured in the arteries b. the lowest pressure measured in the arteries c. determined by stroke volume d. the difference between mean arterial pressure and central venous pressure e. measured only during diastole f. decreased when the capacitance of the arteries decreases

proximal convoluted tubule

Reabsorbs all glucose and amino acids and most HCO3-, Na+, Cl-, PO43-, K+, H2O, and uric acid. Isotonic absorption. Generates and secretes NH3, which enables the kidney to secrete more H+. PTH - inhibits Na+/ PO43- cotransport -> PO43-excretion. AT II - stimulates Na+/H+ exchange -> Na+, H2O, and HCO3− reabsorption 67% Na+ reabsorbed 67% H2O 70% Pi 67% Ca++ 30% Mg++ 50% urea 67% K+

with "salt" corresponding to the outer zona glomerulosa, "sugar" corresponding to the middle zona fasciculata, and "sex" corresponding to the inner zona reticularis.

Remember the mnemonic "Salt, Sugar, and Sex" for the layers of the adrenal cortex and their respective products- name them

31. A 28-year-old man is brought to the emergency department because of blurred vision, fatigue, and severe thirst 20 minutes after being found wandering along a deserted farming road. He reports that his car had run out of gas 3 hours ago, and he walked approximately 7 miles toward his destination without water or shade from the intense summer heat. His current body-weight is 92% of the value listed on his driver's license. His temperature is 39.9 C (103.8), pulse is 105/min, and blood pressure is 95/60 mm Hg. Physical examination shows pale, dry skin. He is occasionally incoherent. He is placed supine on a bed, and intravenous fluids are administered. Within 60 minutes the patient is able to take fluids by mouth and provides additional information about his next of kin before falling asleep. At the time the man was found on the road, which of the following physiologic parameters would have been decreased compared with normal values?

Renal arteriolar perfusion pressure

Ca2+ During repeated stimulation of a muscle fiber, Ca2+ is released from the sarcoplasmic reticulum (SR) more quickly than it can be reaccumulated; therefore, the intracellular [Ca2+] does not return to resting levels as it would after a single twitch. The increased [Ca2+] allows more cross-bridges to form and, therefore, produces increased tension (tetanus). Intracellular Na+ and K+ concentrations do not change during the action potential. Very few Na+ or K+ ions move into or out of the muscle cell, so bulk concentrations are unaffected. Adenosine triphosphate (ATP) levels would, if anything, decrease during tetanus.

Repeated stimulation of a skeletal muscle fiber causes a sustained contraction (tetanus). Accumulation of which solute in intracellular fluid is responsible for the tetanus? Select one: a. Mg2+ b. Adenosine triphosphate (ATP) c. Na+ d. K+ e. Ca2+ f. Troponin g. Cl- h. Calmodulin

Decrease in Na+ and Ca2+ currents

Researchers are conducting a clinical study to examine the properties of a β-receptor antagonist (propranolol) in patients with supraventricular tachycardia. They find that the drug targets the atrioventricular (AV) node and lengthens the PR interval on an electrocardiogram (ECG). In addition to the decrease in AV conduction velocity, they observe that cardiac output is decreased. Which of the following describes the mechanism of action of the drug used in this trial? Select one: a. Decrease in inositol triphosphate b. Increase in cyclic adenosine monophosphate c. Decrease in protein kinase C d. Decrease in Na+ and Ca2+ currents e. Increase in protein kinase A

9. An 18-year-old woman receives general anesthesia for extraction of wisdom teeth. After 5 minutes, she has generalized hypertonicity of skeletal muscles And increased body temperature. The most appropriate treatment is a drug that decreases which of the following?

Sarcoplasmic Ca2+ release

Intracellular receptor complex formation This new drug has a similar mechanism of action to a steroid hormone. Steroid hormones are hydrophobic (or lipophilic), which means that they are able to diffuse across a cell's plasma membrane. Once inside the cell, they may bind to cytosolic receptors to form an intracellular receptor complex, which then translocates into the nucleus or directly binds to intranuclear receptors to modulate gene expression. This drug will act similarly to form an intracellular receptor complex and translocate to the nucleus in the hepatocytes to bind to hormone receptor elements on the DNA. Hormone receptor elements are located in the promoter region of target genes (in this case, LDL receptor genes) to induce transcription of LDL receptor mRNA, which is then translated into LDL receptors that are expressed on the hepatocyte cell surface. The receptors for most steroid hormones are located in the cytoplasm and translocate to the nucleus upon ligand binding. In contrast, receptors for thyroid hormones and vitamin A and D are always located within the nucleus. Although intranuclear modulation of gene expression is the most important mechanism by which steroid hormones work (and which takes longer to take effect), steroid hormones may also bind to plasma membrane proteins and G-protein-coupled receptors (GPCRs) to produce more rapid nongenomic effects. Examples of steroid hormones include sex hormones (estrogen, testosterone), vitamin D, aldosterone, cortisol, and gonadotropins (FSH, LH).

Scientists recently discovered a new drug for treating hypercholesterolemia. In vitro studies with a hepatocyte cell line revealed that this drug increases the number of LDL cholesterol receptors by acting in a manner similar to that of steroids.What is the most important mechanism by which this drug acts on hepatocytes? Select one: a. Allosteric regulation b. Intracellular receptor complex formation c. G-protein-coupled receptor-mediated phosphorylation d. Cell surface receptor antagonism e. Proteolytic modification

dilation of the cervix Suckling and dilation of the cervix are the physiologic stimuli for oxytocin secretion. Milk ejection is the result of oxytocin action, not the cause of its secre- tion. Prolactin secretion is also stimulated by suckling, but prolactin does not directly cause oxytocin secretion. Increased extracellular fluid (ECF) volume and hyperosmolarity are the stimuli for the secretion of the other posterior pituitary hormone, antidiuretic hormone (ADH).

Secretion of oxytocin is increased by Select one: a. increased extracellular fluid (ECF) volume b. milk ejection c. increased prolactin levels d. increased serum osmolarity e. dilation of the cervix

Aldosterone Aldosterone is produced in the zona glomerulosa of the adrenal cortex because that layer contains the enzyme for conversion of corticos- terone to aldosterone (aldosterone synthase). Cortisol is produced in the zona fasciculata. Androstenedione and dehydroepiandrosterone are produced in the zona reticularis. Testosterone is produced in the testes, not in the adrenal cortex.

Selective destruction of the zona glomerulosa of the adrenal cortex would produce a deficiency of which hormone? Select one: a. Androstenedione b. Cortisol c. Dehydroepiandrosterone d. Aldosterone e. Testosterone

Secretion of estrogen and progesterone by the corpus luteum suppresses hypothalamic secretion of GnRH and pituitary secretion of LH Estrogen and progesterone are formed in large amounts by the mature corpus luteum that has formed by 7 days following ovulation, causing nega- tive feedback inhibition of LH secretion from the anterior pituitary.

Seven days after ovulation, pituitary secretion of luteinizing hormone (LH) decreases rapidly. What is the cause of this decrease in secretion? Select one: a. Secretion of estrogen and progesterone by the corpus luteum suppresses hypothalamic secretion of GnRH and pituitary secretion of LH b. the rise in body temperature inhibits hypothalamic release of GnRH c. None of the above d. Estrogen from the developing follicles exerts a feedback inhibition on the hypothalamus e. the anterior pituitary gland becomes unresponsive to the stimulatory effect of gonadotropin-releasing hormone (GnRH)

Do not require adenosine triphosphate (ATP) In contrast to primary and secondary active transport, neither facilitated diffusion nor simple diffusion requires additional energy and, therefore, can work in the absence of ATP. Only facilitated diffusion displays saturation kinetics and involves a carrier protein. By definition, neither simple nor facilitated diffusion can move molecules from low to high concentration. !e concept of specific inhibitors is not applicable to simple diffusion that occurs through a lipid bilayer without the aid of protein.

Simple diffusion and facilitated diffusion share which of the following characteristics? Select one: a. Saturation kinetics b. Transport solute against concentration gradient c. Do not require adenosine triphosphate (ATP) d. Can be blocked by specific inhibitors e. Require transport protein

33. A 53-year-old man is being treated for hypertension and diabetes. His medications include insulin and propranolol. He presents at his physicians office complaining of muscle weakness. Blood tests reveal hyperkalemia (elevated serum potassium) as well as elevated BUN (blood urea nitrogen) propranolol is gradually eliminated and his insulin dosage is adjusted. His serum potassium normalizes and his muscle weakness is alleviated. What probably caused his muscle weakness?

Skeletal muscle depolarization with resultant Na-channel inactivation

4.8x10-2

Solution A and Solution B are separated by a membrane whose permeability to glycerol is 4 x 10−3 cm/s and whose surface area is 2 cm2. The concentration of glycerol in A is 8 mg/mL, and the concentration of glycerol in B is 2 mg/mL. The partition coefficient for glycerol is 10-2, as measured in an oil-water mixture. Diffusion coefficient of glycerol is 4. What are the initial rate and direction of net diffusion of glycerol? Select one: a. 2x10-5 b. 3.6x10-4 c. 5x10-4 d. 4.8x10-2 e. 1x10-3

solution A is -30 mV The membrane is permeable to Ca2+, but impermeable to Cl-. Although there is a concentration gradient across the membrane for both ions, only Ca2+ can diffuse down this gradient. Ca2+ will diffuse from solution A to solution B, leaving negative charge behind in solution A. The magnitude of this voltage can be calculated for electrochemical equilibrium with the Nernst equation as follows: ECa2+ = 2.3 RT/zF log CA/CB = 60 mV/+2 log 10 mM/1 mM = 30 mV log 10 = 30 mV. The sign is determined with an intuitive approach—Ca2+ diffuses from solution A to solution B, so solution A develops a negative voltage (-30 mV). Net diffusion of Ca2+ will cease when this voltage is achieved, that is, when the chemical driving force is exactly balanced by the electrical driving force (not when the Ca2+ concentrations of the solutions become equal).

Solutions A and B are separated by a membrane that is permeable to Ca2+ and impermeable to Cl-. Solution A contains 10mM CaCl2, and solution B contains 1 mM CaCl2. Assuming that 2.3 RT/F = 60 mV, Ca2+ will be at electrochemical equilibrium when a. the Ca2+ concentrations of the two solutions are equal b. solution A is +30 mV c. solution A is -30 mV d. solution A is -120 mV e. solution A is -60 mV f. the Cl- concentrations of the two solutions are equal g. solution A is +120 mV h. solution A is +60 mV

triple Flux is proportional to the concentration difference across the membrane, J = -PA (CA - CB). Originally, CA - CB = 10 mM - 5 mM = 5 mM. When the urea concentration was doubled in solution A, the concentration difference became 20 mM - 5 mM = 15 mM, or three times the original difference. Therefore, the flux would also triple. Note that the negative sign preceding the equation is ignored if the lower concentration is subtracted from the higher concentration.

Solutions A and B are separated by a membrane that is permeable to urea. Solution A is 10 mM urea, and solution B is 5 mM urea. If the concentration of urea in solution A is doubled, the flux of urea across the membrane will Select one: a. decrease to one-third b. triple c. be unchanged d. double e. decrease to one-half

K+ will diffuse from solution A to solution B until a membrane potential develops with solution A negative with respect to solution B Because the membrane is permeable only to K+ ions, K+ will diffuse down its concentration gradient from solution A to solution B, leaving some Cl- ions behind in solution A. A diffusion potential will be created, with solution A negative with respect to solution B. Generation of a diffusion potential involves movement of only a few ions and, therefore, does not cause a change in the concentration of the bulk solutions.

Solutions A and B are separated by a semipermeable membrane that is permeable to K+, but not to Cl-. Solution A is 100 mM KCl, and solution B is 1 mM KCl. Which of the following statements about solution A and solution B is true? a. K+ will diffuse from solution A to solution B until a membrane potential develops with solution A negative with respect to solution B b. K+ will diffuse from solution A to solution B until a membrane potential develops with solution A positive with respect to solution B c. K+ ions will diffuse from solution B to solution A until the [K+ ] of both solutions is 50.5 mM d. K+ ions will diffuse from solution A to solution B until the [K+ ] of both solutions is 50.5 mM e. KCl will diffuse from solution A to solution B until the [KCl] of both solutions is 50.5 mM

Solution A is hyperosmotic with respect to solution B, and the solutions are isotonic Solution A contains both sucrose and urea at concentrations of 1 mM, whereas solution B contains only sucrose at a concentration of 1 mM. The calculated osmolarity of solution A is 2 mOsm/L, and the calculated osmolarity of solution B is 1 mOsm/L. Therefore, solution A, which has a higher osmolarity, is hyperosmotic with respect to solution B. Actually, solutions A and B have the same effective osmotic pressure (i.e., they are isotonic) because the only "effective" solute is sucrose, which has the same concentration in both solutions. Urea is not an effective solute because its reflection coefficient is zero.

Solutions A and B are separated by a semipermeable membrane. Solution A contains 1mMsucrose and 1 mM urea. Solution B contains 1 mM sucrose. The reflection coefficient for sucrose is one and the reflection coefficient for urea is zero. Which of the following statements about these solutions is correct? Select one: a. Solutions A and B are isosmotic b. Solution A is hyposmotic with respect to solution B, and the solutions are isotonic c. Solution A has a higher effective osmotic pressure than solution B d. Solution A has a lower effective osmotic pressure than solution B e. Solution A is hyperosmotic with respect to solution B, and the solutions are isotonic Feedback

inhibin the Sertoli cells of the seminiferous tubules secrete inhibin at a rate proportional to the rate of pro- duction of sperm cells. Inhibin has a direct inhibitory effect on anterior pituitary secretion of FSH. FSH binds to specific receptors on the Sertoli cells, causing the cells to grow and secrete substances that stimulate sperm cell production. e secretion of inhibin thereby provides the negative feedback control signal from the seminiferous tubules to the pituitary gland.

Spermatogenesis is regulated by a negative feedback control system in which follicle-stimulating hormone (FSH) stimulates the steps in sperm cell formation. What is the negative feedback signal associated with sperm cell production that inhibits pituitary formation of FSH? Select one: a. Testosterone b. Estrogen c. Luteinizing hormone d. Inhibin

74. A pig farmer accidentally infected himself with a high dose of follicle-stimulating hormone [FSH]. He is very concerned, since he read that FSH stimulates Estrogen production in the testes. The physician explains that only a tiny amount of estrogen is produced that way and that it will not cause any Feminization, but rather, the estrogen is necessarily for which of the following?

Support of spermatogenesis

Neonatal Respiratory Distress Syndrome

Surfactant deficiency -> increased surface tension -> alveolar collapse in premature neonates

Conformational change of the hormone-receptor complex The steroid hormone circulates in the plasma bound to a hormone-specific binding globulin. At the target organ, it crosses the cell membrane due to its lipophilic properties and binds to an intracellular receptor either in the cytoplasm or within the nucleus. The hormone-receptor complex then undergoes a conformational change, which reveals the receptor's DNA-binding domain; without this step, it is unable to carry out its action and bind to DNA. Once the binding domain is revealed, the hormone-receptor complex binds the DNA enhancer element and causes changes to gene expression at the transcriptional level. Binding of the steroid hormone to a hormone-specific globulin helps the hormone reach its target cell population, but does not immediately precede binding to DNA. Steroid hormones do not act through transmembrane receptors and second messengers. Although binding to a DNA enhancer element is the desired action of the hormone, this is the final step in its signaling pathway, not the one immediately preceding it. Binding to an intracellular steroid receptor alone is also not the correct answer, since conformational change of the hormone-receptor complex must occur before the steroid hormone-receptor complex binds to DNA.

Steroid hormones are unique in that they enter the cell and act directly on DNA to effect gene expression level changes, rather than acting only through intermediary signaling proteins.Which of the following steps immediately precedes steroid hormone-receptor complex binding to DNA? Select one: a. Hormone binding to a hormone-specific globulin b. Hormone binding to a DNA enhancer element c. Conformational change of the hormone-receptor complex d. Hormone binding to a membrane receptor e. Hormone binding to its intracellular receptor

H Drinking a hyperosmotic solution will first increase extracellular fluid (ECF) volume and osmolarity. The hyperosmolarity of the ECF will promote water diffusion from the intracellular fluid (ICF) compartment to the extracellular compartment until the osmolarity of both compartments is equal, thus reducing intracellular volume and increasing intracellular osmolarity. All of these shifts are represented by box c (increased osmolarity of ICF and ECF, increased volume of ECF, and decreased volume of ICF). Drinking a hypoosmotic solution will first increase extracellular fluid (ECF) volume but decrease extracellular fluid osmolarity. The hypoosmolarity of the ECF will promote diffusion of water from the extracellular compartment to the intracellular compartment until the osmolarity of both compartments is equal, thus increasing intracellular volume and but decreasing intracellular osmolarity. All of these shifts are represented by box B (decreased osmolarity of ICF and ECF, increased volume of ICF and ЕCF).

Subjects 1 and 2 are both 70-kg male subjects with the same total body water; depicted by the "normal state"in the image. Subject 1 drinks a hyperosmotic saline solution, while Subject 2 drinks a hypoosmotic saline solution. After steady-state equilibrium is achieved, which diagram best represents the volume and osmolarity shift for each subject? Select one: a. A b. B c. C d. D e. E f. F g. G h. H i. I j. J k. K l. L

higher urine osmolarity After drinking distilled water, subject A will have an increase in intracellular fluid (ICF) and extracellular fluid (ECF) vol- umes, a decrease in plasma osmolarity, a suppression of antidiuretic hormone (ADH) secretion, and a positive free-water clearance (CH2O), and will produce dilute urine with a high flow rate. Subject B, after drinking the same volume of isotonic NaCl, will have an increase in ECF volume only and no change in plasma osmolarity. Because subject B's ADH will not be suppressed, he will have a higher urine osmolarity, a lower urine flow rate, and a lower CH2O than subject A.

Subjects A and B are 70-kg men. Subject A drinks 2 L of distilled water, and subject B drinks 2 L of isotonic NaCl. As a result of these ingestions, subject B will have a Select one: a. greater change in plasma osmolarity b. higher positive free-water clearance (CH2O) c. higher urine flow rate d. greater change in intracellular fluid (ICF) volume e. higher urine osmolarity

Palatopharyngeal folds The palatopharyngeal folds located on each side of the pharynx are pulled medially forming a sagittal slit through which the bolus of food must pass. This slit performs a selective function, allowing food that has been masticated su fficiently to pass by but impeding the passage of larger objects. The soft palate is pulled upward to close the posterior nares, which prevents food from passing into the nasal cavities. The vocal cords of the larynx are strongly approximated during swallowing, and the larynx is pulled upward and anteriorly by the neck muscles. The epiglottis then swings backward over the opening of the larynx. The upper esophageal sphincter relaxes, allowing food to move from the posterior pharynx into the upper esophagus.

Swallowing is a complex process that involves signaling between the pharynx and swallowing center in the brainstem. Which of the following structures is critical for determining whether a bolus of food is small enough to be swallowed? Select one: a. Palatopharyngeal folds b. Upper esophageal sphincter c. Larynx d. Epiglottis e. Soft palate

70. A 20-year-old female tennis player has just won a tennis match on a warm summer day. Her blood pressure at this time is 135/70 with a heart rate of 140 Beats per minute and a respiratory rate of 25 per minute. She is flushed and sweating profusely. Compared to the resting state, what can be said about The level of activity of sympathetic nerves to her heart adn to her cutaneous vasculature?

Sympathetic effects on the heart is increased while the cutaneous vasculature decreased

A THe PO2 of mixed venous blood entering the pul- monary capillaries increases during its transit through the pulmonary capillaries (from 40 mm Hg to 104 mm Hg) and the PCO2 decreases simultaneously from 45 mm Hg to 40 mm Hg. us, PO2 is represented by the red lines and PCO2 is represented by the green lines in the various diagrams. During resting conditions, oxygen has a 64 mm Hg pressure gradient (104 - 64 = 64 mm Hg) and carbon dioxide has a 5 mm Hg pres- sure gradient (45 - 40 = 5 mm Hg) between the blood at the arterial end of the capillaries and the alveolar air.

THe diagrams show changes in the partial pressures of oxygen and carbon dioxide as blood flows from the arterial end to the venous of the pulmonary capillaries.Which diagram best depicts the normal relationship between PO2 and PCO2 during resting conditions? Select one: a. A b. B c. C d. D e. E

Carbon monoxide It is not practical to measure the oxygen diffusing capacity directly because it is not possible to measure accurately the oxygen tension of the pulmonary capil- lary blood. However, the diffusing capacity for carbon monoxide (CO) can be measured accurately because the CO tension in pulmonary capillary blood is zero under normal conditions. e CO diffusing capacity is then used to calculate the oxygen diffusing capacity by taking into account the differences in diffusion coefficient between oxygen and CO. Knowing the rate of transfer of CO across the respiratory membrane is often helpful for evaluating the presence of possible parenchymal lung disease when spirometry and/or lung volume determinations suggest a reduced vital capacity, residual volume and/or total lung capacity.

THe diffusing capacity of a gas is the volume of gas that will diffuse through a membrane each minute for a pressure difference of 1 mm Hg. Which of the following gases is often used to estimate the oxygen diffusing capacity of the lungs? Select one: a. Cyanide gas b. Carbon dioxide c. Carbon monoxide d. Nitrogen e. Oxygen

Emphysema THe forced vital capacity (FVC) is the vital capacity measured with a forced expiration (FVC 4.0 L for patient Z). e forced expiratory volume in one sec- ond (FEV1) is the amount of air that can be expelled from the lungs during the first second of a forced expi- ration (FVC 2.0 L for patient Z). FEV1/FVC is a function of airway resistance. Airway resistance is of- ten increased in emphysematous lungs, which causes FEV1/FVC to decrease. Note that FEV1/FVC is 50% in patient Z and 80% in the healthy individual repre- sented by curve X. e FEV1/FVC ratio is not usually affected in pleural effusion and pneumothorax be- cause airway resistance is normal. FVC is often de- creased in asbestosis, fibrotic pleurisy, silicosis, and tuberculosis and the FEV1/FVC ratio is either normal or slightly increased.

THe following diagram shows forced expirations from a person with healthy lungs (curve X) and from a patient (curve Z). Which of the following can best explain the results from the patient? Select one: a. Silicosis b. Emphysema c. Fibrotic pleurisy d. Tuberculosis e. Asbestosis f. Pneumothorax g. Pleural effusion

Emphysema In obstructive diseases such as emphysema and asthma, the maximum expiratory flow-volume (MEFV) curve begins and ends at abnormally high lung vol- umes, and the flow rates are lower than normal at any given lung volume. e curve may also have a scooped out appearance, as shown on the diagram. e other diseases listed as answer choices are constricted lung diseases (often called restrictive lung diseases). Lung volumes are lower than normal in constricted lung diseases.

THe maximum expiratory flow-volume curves shown in the next diagram were obtained from a healthy individual (red curve) and a 57-year-old man who complains of shortness of breath (green curve). Whichof the following disorders is most likely present in the man? Select one: a. Asbestosis b. Silicosis c. Emphysema d. Scoliosis e. Kyphosis

Patient 5 With hypoventilation, alveolar ventilation decreases, which leads to a decrease in Pao2 (below 80 mm Hg) because ventilation is reduced, and an increase in PACO2 (above 45 mm Hg) because CO2 is retained. (A, C, D, E). These answers do not represent the correct values for hypoventilation

The arterial PO2 and arterial PCO2 from five patients in the intensive care unit are shown. Which patient is most likely hypoventilating? Select one: a. Patient 1 b. Patient 2 c. Patient 3 d. Patient 4 e. Patient 5

Vagotomy The cephalic phase of gastric secretion occurs before food enters the stomach. Seeing, smelling, chewing, and anticipating food is perceived by the brain, which, in essence, tells the stomach to prepare for a meal. Stimuli for the cephalic phase thus include mechanoreceptors in the mouth, chemoreceptors (smell and taste), thought of food, and hypoglycemia. Because the cephalic phase of gastric secretion is mediated entirely by way of the vagus nerve, vagotomy can abolish the response. Antacids neutralize gastric acid, but they do not inhibit gastric secretion. An antigastrin antibody would attenuate (but not abolish) the cephalic phase because this would have no effect on histamine and acetylcholine stimulation of acid secretion. Atropine would attenuate the cephalic phase by blocking acetylcholine receptors on parietal cells; however, atropine does not abolish acetylcholine stimulation of gastrin secretion. A histamine H2 blocker would attenuate the cephalic phase of gastric secretion, but would not abolish it.

The cephalic phase of gastric secretion accounts for about 30% of the acid response to a meal. Which of the following can totally eliminate the cephalic phase of gastric secretion? Select one: a. Vagotomy b. Anti-gastrin antibody c. Histamine H2 blocker d. Sympathectomy e. Atropine f. Antacids (e.g., Rolaids)

increased mean systemic pressure The shift in the venous return curve to the right is consistent with an increase in blood volume and, as a consequence, mean systemic pressure. Both cardiac output and venous return are increased in the new steady state (and are equal to each other). Contractility is unaffected

The change indicated by the dashed lines on the cardiac output/venous return curves shows Select one: a. decreased blood volume b. increased mean systemic pressure c. decreased venous return in the "new" steady state d. increased myocardial contractility e. decreased cardiac output in the "new" steady state

A Band

What part of the sarcomere does not change in length?

4, 2, 1, 3 a meal, the pH of the gastric contents increases because the food buff ers the acid in the stomach. " is increase in pH suppresses the release of somatostatin from delta cells in the stomach (hydrogen ions stimulate the release of somatostatin). Because somatostatin inhibits secretion of both gastrin and gastric acid, the fall in somatostatin levels leads to an increase in acid secretion. " e increase in acid secretion causes the pH of the gastric contents to decrease. As the pH of the gastric contents decreases, the rate of acid secretion also decreases.

The control of gastric acid secretion in response to a meal involves several events that take place over a 4- or 5-hr period following the meal. "ese events include (1) a decrease in the pH of the gastric contents, (2) an increase in the rate of acid secretion, (3) a decrease in the rate of acid secretion, and (4) an increase in the pH of the gastric contents. Which of the following best describes the correct temporal order of events over a 4- or 5-hr period following a meal? Select one: a. 1, 3, 2, 4 b. 3, 1, 4, 2 c. 4, 3, 2, 1 d. 3, 4, 1, 2 e. 1, 2, 3, 4 f. 2, 3, 1, 4 g. 2, 1, 4, 3 h. 4, 2, 1, 3

Movement of Na+ into the cell At point B in this action potential, Vm has reached threshold potential and has triggered the opening ofvoltage-gated Na! channels. ! e resulting Na! influx is responsible for the rapid, self-perpetuating depolarization phase of the action potential.

The diagram shows the change in membrane potential during an action potential in a giant squid axonWhich of the following is primarily responsible for the change in membrane potential between points B and D? Select one: a. Movement of K+ out of the cell b. Movement of Na+ out of the cell c. Movement of Na+ into the cell d. Movement of K+ into the cell e. Inhibition of the Na+, K+-ATPase

increased contractility An upward shift of the cardiac output curve is consistent with an increase in myocardial contractility; for any right atrial pressure (sarcomere length), the force of contraction is increased. Such a change causes an increase in stroke volume and cardiac output. Increased blood volume and increased mean systemic pressure are related and would cause a rightward shift in the venous return curve. A negative inotropic agent would cause a decrease in contractility and a downward shift of the cardiac output curve.

The dashed line in the figure illustrates the effect of Select one: a. increased contractility b. increased total peripheral resistance (TPR) c. a negative inotropic agent d. increased mean systemic pressure e. increased blood volume

30 mg/h

The diagram below illustrates the concentration of a substance in two chambers. If the concentration of the substance in chamber A doubles, the diffusion of the substance will change from 10 mg/h to which of the following? Select one: a. 30 mg/h b. 5 mg/h c. 10 mg/h d. 15 mg/h e. 20 mg/h

Myosin ATPase activity The diagram shows that the maximum velocity of shortening (Vmax) occurs when there is no afterload on the muscle (force # 0). Increasing afterload decreases the velocity of shortening until a point is reached where shortening does not occur (isometric contraction) and contraction velocity is thus 0 (where curves intersect X-axis). The maximum velocity of shortening is dictated by the ATPase activity of the muscle, increasing to high levels when the ATPase activity is elevated. Choice A: Increasing the frequency of muscle contraction will increase the load that a muscle can lift within the limits of the muscle, but will not affect the velocity of contraction. Choices B, C, and E: Muscle hypertrophy, increasing muscle mass, and recruiting additional motor units will increase the maximum load that a muscle can lift, but these will not affect the maximum velocity of contraction.

The diagram shows the force-velocity relationship for isotonic contractions of skeletal muscle. The differences in the three curves result from differences in which of the following? Select one: a. Muscle mass b. Recruitment of motor units c. Myosin ATPase activity d. Hypertrophy e. Frequency of muscle contraction

There is optimal overlap between the actin and myosin filaments Tension development in a single sarcomere is directly proportional to the number of active myosin cross-bridges attached to actin filaments. Overlap between the myosin and actin filaments is optimal at sarcomere lengths of about 2.0 to 2.5 micrometers, which allows maximal contact between myosin heads and actin filaments. At lengths less than 2.0 micrometers, the actin filaments protrude into the H band, where no myosin heads exist. At lengths greater than 2.5 micrometers, the actin filaments are pulled toward the ends of the myosin filaments, again reducing the number of possible cross-bridges.

The diagram shows the length-tension relationship for a single sarcomere. The length-tension diagram of single vertebrate striated muscle fibers. Why is the tension development maximal between points B and C? Select one: a. There is minimal overlap between the actin and myosin filaments b. The Z discs of the sarcomere abut the ends of the myosin filament c. The myosin filament is at its minimal length d. There is optimal overlap between the actin and myosin filaments e. Myosin filaments are overlapping each other f. Actin filaments are overlapping each other

Diagram C A 3% solution of sodium chloride is hypertonic and when infused into the extracellular fluid would raise osmolarity, thereby causing water to flow out of the cells into the extracellular fluid until osmotic equi- librium is achieved. In the steady state, extracellular fluid volume would increase, intracellular fluid volume would decrease, and osmolarity of both compartments would increase.

The diagrams represent various states of abnormal hydration. In each diagram, the normal state (orange and lavender) is superimposed on the abnormal state (dashed lines) to illustrate the shifts in the volume (width of rectangles) and total osmolarity (height of rectangles) of the extracellular and intracellular fluid compartments. Which of the diagrams represents the changes (after osmotic equilibrium) in extracellular and intracellular fluid volumes and osmolarities after the infusion of 3% sodium chloride? Select one: a. A b. B c. C d. D e. E

Diagram D In a patient with central diabetes insipidus there would be deficient secretion of antidiuretic hormone, resulting in excretion of large volumes of water. is, in turn, would cause dehydration and hypernatremia (increased plasma osmolarity). e hypernatremia would result in decreased intracellular volume. ere- fore, the primary loss of water would lead to increases in both extracellular and intracellular fluid osmolarity as well as decreases in intracellular and extracellular fluid volumes.

The diagrams represent various states of abnormal hydration. In each diagram, the normal (solid lines) is superimposed on the abnormal state (dashed lines) to illustrate the shifts in the volumes (width of rectangles) and total osmolarities (height of rectangles) of the extracellular fluid and intracellular fluid compartments. Which of the diagrams would represent the changes (after osmotic equilibrium) in extracellular and intracellular fluid volumes and osmolarities in a patient with severe "central" diabetes insipidus? Select one: a. A b. B c. C d. D

E

The figure shows the aortic pressure, left ventricular pressure, and left atrial pressure during one cardiac cycle. Which of the following sets of data most closely corresponds to the figure? Select one: a. A b. E c. B d. C

0.05 mm Hg/mL/min The student must first recognize that the four organs are arranged in parallel The total resistance of the circuit (RT) is then calculated as follows 1/RT=1/0.2 +1/0.2 + 1/0.2 + 1/0.2=20 mm Hg/mL/min Therefore. RT=1/20=0.05 mm Hg/mL/min. The student should recall that adding resistances (R1, R2, R3...) in parallel reduces the total resistance (RT) of a circuit because of the manner in which parallel resistances are added, 1/RT=1/R1 + 1/R2 + 1/R3. Note also from the equation that removing a parallel resistance will increase the total resistance

The figure shows the vascular systems of four organs with resistances 1-4 The arterial inflow pressures and venous outflow pressures are the same for all organs Assuming that the resistance of the feed vessels is negligible, what is the total resistance of the entire circuit if the resistance of each of the four organs is 0.20 mm Hg/mL/min? Select one: a. 0.02 mm Hg/mL/min b. 0.05 mm Hg/mL/min c. 0.01 mmHg/mL/min d. 0.04 mm Hg/mL/min e. 20 mm Hg/mL/min

60 Breathing 100% oxygen has a limited effect on the arterial PO2 when the cause of arterial hypoxemia is a vascular shunt. However, breathing 100% oxygen raises the arterial PO2 to over 600 mm Hg in a nor- mal subject. With a vascular shunt, the arterial PO2 is determined by (a) highly oxygenated end-capillary blood (PO2 600 mm Hg) that has passed through ventilated portions of the lung, and (b) shunted blood that has bypassed the ventilated portions of the lungs and thus has an oxygen partial pressure equal to that of mixed venous blood (PO2 40 mm Hg). A mixture of the two bloods causes a large fall in PO2 because the oxygen dissociation curve is so flat in its upper range.

The following diagram shows a lung with a large shunt in which mixed venous bypasses the oxygen exchangeareas of the lung. Breathing room air produces the oxygen partial pressures shown on the diagram. Whatis the oxygen tension of the arterial blood (in mm Hg) when the person breathes 100% oxygen and the inspired oxygen tension is over 600 mm Hg? Select one: a. 55 b. 60 c. 175 d. 200 e. 40

Fecal incontinence (i.e., no control over defecation) Prior to pelvic floor training, the pressure at the external anal sphincter was unchanged following inflation of the rectal balloon. " is failure of the external anal sphincter to contract is expected to result in defecation. After pelvic floor training, the external anal sphincter contracts when the rectal balloon is inflated, which prevents inappropriate defecation

The following diagram shows manometric recordings from a patient before and after pelvic floor training. A balloon placed in the rectum was blown up (arrows) and deflated repeatedly. Tracing Z is a manometric recording obtained from the external anal sphincter before and after pelvic floor training. Which of the following best describes the condition for which the patient received pelvic floor training? Select one: a. Hirschsprung disease b. Anal fissure (i.e., tear or superficial laceration) c. Chronic diarrhea d. Fecal incontinence (i.e., no control over defecation) e. Hemorrhoids

Internal anal sphincter The internal anal sphincter relaxes when the rectum is stretched, as indicated by repeated decreases in pressure following inflation of the rectal balloon. Pressures in the distal and proximal rectum are expected to increase following inflation of the rectal balloon. Inflation of a rectal balloon should not affect pressures at the lower esophageal sphincter or ileocecal valve.

The following diagram shows manometric recordings from a patient before and after pelvic floor training. A balloon placed in the rectum was blown up (arrows) and deflated repeatedly. Tracing Z is a manometric recording obtained from the external anal sphincter before and after pelvic floor training. Which of the following best describes the origin of tracing X shown in the upper panel? Select one: a. Internal anal sphincter b. Distal rectum c. Proximal rectum d. Ileocecal valve e. Lower esophageal sphincter

6.25 L/min Cardiac output is calculated by the Fick principle if whole body oxygen (O2) consumption and [O2] in the pulmonary artery and pulmonary vein are measured. Mixed venous blood could substitute for a pulmonary artery sample, and BRS Physiologyperipheral arterial blood could substitute for a pulmonary vein sample. Central venous pressure and heart rate are not needed for this calculation.

The following measurements were obtained in a male patient: Central venous pressure: 10 mm Hg Heart rate: 70 beats/min Pulmonary vein [O2] = 0.24 mL O2/mL Pulmonary artery [O2] = 0.16 mL O2/mL Whole body O2 consumption: 500 mL/min What is this patient's cardiac output? Select one: a. 4.55 L/min b. 6.25 L/min c. 1.65 L/min d. 5.00 L/min e. 8.00 L/min

6.25 L/min Cardiac output is calculated by the Fick principle if whole body oxygen (O2) consumption and [O2] in the pulmonary artery and pulmonary vein are measured. Mixed venous blood could substitute for a pulmonary artery sample, and BRS peripheral arterial blood could substitute for a pulmonary vein sample. Central venous pressure and heart rate are not needed for this calculation.

The following measurements were obtained in a male patient: Central venous pressure: 10 mm HgHeart rate: 70 beats/minPulmonary vein [O2] = 0.24 mL O2/mLPulmonary artery [O2] = 0.16 mL O2/mLWhole body O2 consumption: 500 mL/min What is this patient's cardiac output? Select one: a. 8.00 L/min b. 5.00 L/min c. 6.25 L/min d. 1.65 L/min e. 4.55 L/min

60 ml/min GFR is equal to the clearance of inulin. Inulin clearance = urine inulin concentration (60 mg/ml) x urine flow rate (2 ml/min)/plasma inulin concentra- tion (2 mg/ml) = 60 ml/min.

The following test results were obtained: urine flow rate = 2.0 ml/min; urine inulin concentration = 60 mg/ml; plasma inulin concentration = 2 mg/ml; urine potassium concentration = 20 (mol/ml; plasma potassium concentration = 4.0 (mol/ml; urine osmolarity = 150 mOsm/L; and plasma osmolarity = 300 mOsm/L. What is the approximate GFR? Select one: a. 75 ml/min b. 25 ml/min c. 20 ml/min d. 30 ml/min e. 60 ml/min

D Damage to the gastric mucosal barrier allows hydrogen ions to back-leak into the mucosa in exchange for sodium ions. A low pH in the mucosa causes mast cells to leak histamine, which damages the vasculature causing ischemia. " e ischemic mucosa allows a greater leakage of hydrogen ions—more cell injury and death—resulting in a vicious cycle. Factors that normally strengthen the gastric mucosal barrier include mucus (which impedes the influx of hydrogen ions), gastrin (which stimulates mucosal growth), certain prostaglandins (which can stimulate mucus secretion), and various growth factors that can stimulate growth of blood vessels, gastric mucosa, and other tissues. Factors that weaken the gastric mucosal barrier include Helicobacter pylori (a bacterium that produces toxic levels of ammonium) as well as aspirin, NSAIDS, ethanol, and bile salts.

The gastric mucosal barrier has a physiological and an anatomical basis to prevent back-leak of hydrogen ions into the mucosa. Some factors are known to strengthen the integrity of the gastric mucosal barrier, whereas other factors can weaken the barrier. Which of the following factors strengthen or weaken the barrier? Select one: a. D b. C c. B d. E e. A

Proton pump inhibitor A proton pump inhibitor such as omeprazole inhibitsall acid secretion by directly inhibiting the H!, K!-ATPase (H! pump). "e parietal cell has receptors for secretagogues such as gastrin, acetylcholine, and histamine. "erefore, antigastrin antibodies, atropine, and histamine H2 blockers can reduce the secretion of acid, but none of these can totally eliminate acid secretion. Antacids neutralize gastric acid once it has entered the stomach, but they cannot inhibit acid secretion from parietal cells.

The gastric phase of gastric secretion accounts for about 60% of the acid response to a meal. Which of the following can virtually eliminate the secretion of acid during the gastric phase? Select one: a. Antiacids (e.g., Rolaids) b. Antigastrin antibodies c. Proton pump inhibitor d. Atropine e. Histamine H2 blocker

B Gastrin stimulates gastric acid secretion, and secretin and GLIP inhibit gastric acid secretion under normal, physiological conditions. It is important to differentiate the physiological effects of the gastrointestinal hormones from their pharmacological actions. For example, gastrin and cholecystokinin (CCK) have identical actions on gastrointestinal function when large, pharmacological doses are administered, but they do not share any actions at normal, physiological concentrations. Likewise, GLIP and secretin share multiple actions when pharmacological doses are administered, but only one action is shared at physiological concentrations: inhibition of gastric acid secretion.

The gastrointestinal hormones have physiological effects that can be elicited at normal concentrations as well as pharmacological effects that require higher than normal concentrations. What is the direct physiological effect of the various hormones on gastric acid secretion? (GLIP, glucose-dependent insulinotropic peptide) Select one: a. E b. C c. A d. B e. D

E Cholecystokinin (CCK) is the only gastrointestinal hormone that inhibits gastric emptying under normal,physiological conditions. CCK inhibits gastric emptying by relaxing the orad stomach, which increases its compliance. When the compliance of the stomach is increased, the stomach can hold a larger volume of food without excess build up of pressure in the lumen. None of the gastrointestinal hormones increase gastric emptying under physiological conditions; however, gastrin, secretin, and GLIP can inhibit gastric emptying when pharmacological doses are administered experimentally.

The gastrointestinal hormones have physiological effects that can be elicited at normal concentrations as well as pharmacological effects that require higher than normal concentrations. What is the physiological effect of the various hormones on gastric emptying? Select one: a. A b. B c. F d. D e. E f. C

They have the greatest resistance The decrease in pressure at any level of the cardiovascular system is caused by the resistance of the blood vessels (∆P = Q × R). The greater the resistance is, the greater the decrease in pressure is. The arterioles are the site of highest resistance in the vasculature. The arterioles do not have the greatest surface area or cross-sectional area (the capillaries do). Velocity of blood flow is lowest in the capillaries, not in the arterioles.

The greatest pressure decrease in the circulation occurs across the arterioles because Select one: a. they have the greatest cross-sectional area b. they have the greatest surface area c. the velocity of blood flow through them is the lowest d. they have the greatest resistance e. the velocity of blood flow through them is the highest

it will lead to lower amplitude of depolarization

The inactivation gates on the Na+ channels are closing (by depolarization), but their response is slower than the opening of the activation gates (this is normal) If you saw a faster inactivation of sodium channels how would that affect the action potential?

the number of motor units recruited by the central nervous system (CNS) and by their frequency of activation

The increase in the force of contraction of skeletal muscle is regulated by?

hypertension and hypokalemia

The increased levels of mineralocorticoids lead to increased sodium retention and potassium excretion, which leads to?

Point D The plateau phase (phase 2) is the result of the influx of calcium. Although calcium channels begin to open during the upstroke (phase 0), the greatest number of cal- cium channels is open during the plateau. The upstroke is primarily depen- dent on the opening of Na+ channels. The initial repolarization (phase 1) is dependent on the inactivation of Na+ channels and the opening of a tran- sient K+ channel. Repolarization (phase 3) is produced by the inactivation of Ca2+ channels and the activation of the delayed rectifier K+ channels

The phases of the ventricular muscle action potential are represented by the lettered points on the diagram below. At which point on the ventricular action potential is membrane potential most dependent on calcium permeability? Select one: a. Point E b. Point A c. Point C d. Point B e. Point D

-7 the pleural pressure (sometimes called the intra- pleural pressure) is the pressure of the fluid in the nar- row space between the visceral pleura of the lungs and parietal pleura of the chest wall. e pleural pres- sure is normally about 5 cm H2O immediately before inspiration (i.e., at functional residual capacity, FRC) when all of the respiratory muscles are relaxed. During inspiration, the volume of the chest cavity increases and the pleural pressure becomes more negative. e pleural pressure averages about 7.5 cm H2O immedi- ately before expiration when the lungs are fully ex- panded. e pleural pressure then returns to its resting value of 5 cm H2O as the diaphragm relaxes and lung volume returns to FRC. erefore, the intrapleural pressure is always subatmospheric under normal con- ditions varying between 5 and 7.5 cm H2O during quiet breathing.

The pleural pressure of a normal 56-year-old woman is approximately = 5 cm H2O during resting conditions immediately before inspiration (i.e., at functional residual capacity). What is the pleural pressure (in cm H2O) during inspiration? Select one: a. 0 b. +4 c. -7 d. -3 e. +1

Gastric glands of the stomach Pepsinogen is the precursor of the enzyme pepsin. Pepsinogen is secreted from the peptic or chief cells of the gastric gland (also called the oxyntic gland). To be converted from the precursor form to the active form (pepsin), pepsinogen must come in contact with hydrochloric acid or pepsin itself. Pepsin is a proteolytic enzyme that digests collagen and other types of connective tissue in meats

The proenzyme pepsinogen is secreted mainly from which of the following structures? Select one: a. Ductal cells of the pancreas b. Gastric glands of the stomach c. Acinar cells of the pancreas d. Epithelial cells of the duodenum

Bronchioles The larger bronchi near to the trachea have the greatest resistance to airflow in the healthy lung. How- ever, in disease conditions, the smaller bronchioles often have a far greater role in determining resistance because (a) they are easily occluded because of their small size, and (b) they have an abundance of smooth muscle in their walls and therefore constrict easily.

The resistance of the pulmonary tree is so low that a 1 cm of water pressure gradient is sufficient to cause normal air flow during resting conditions. Which of the following often has a substantial resistance during pulmonary disease states that can limit alveolar ventilation? Select one: a. Bronchioles b. Large bronchi c. Trachea d. Small bronchi e. Alveoli

K+ The resting potential of any cell is dependent on the concentration gradients of the permeant ions and theirrelative permeabilities (Goldman equation). In the myelinated nerve fiber, as in most cells, the resting membraneis predominantly permeable to K!. !e negative membrane potential observed in most cells (including nerve cells) is due primarily to the relatively high intracellular concentration and high permeability of K!.

The resting potential of a myelinated nerve fiber is primarily dependent on the concentration gradient of which of the following ions? Select one: a. HCO3- b. Na+ c. Cl- d. Ca+ e. K+

Ca2+ Quantitatively, the driving force on any given ion is the difference in millivolts between the membrane potential (Vm) and the equilibrium potential for that ion (Eion). In this cell, EK = -61 millivolts, ECl = - 61 millivolts, ENa = + 61 millivolts, and ECa = 525 millivolts. Therefore, Ca!! is the ion with the equilibrium potential farthest from Vm. This means that Ca!! would have the greatest tendency to cross the membrane through an open channel (in this particular example).

The table shows the concentrations of four ions across the plasma membrane of a model cell. Refer to this table when answering the following four questions If the membrane potential of this cell is -80 millivolts, the driving force is greatest for which ion? Select one: a. Ca2+ b. Cl- c. K+ d. Na+

- 61 millivolts

The table shows the concentrations of four ions across the plasma membrane of a model cell. Refer to this table when answering the following four questions What is the equilibrium potential for K+ across the plasma membrane of this cell? Select one: a. -122 millivolts b. 61 millivolts c. -61 millivolts d. 122 millivolts e. 0 millivolts

-61 millivolts The equilibrium potential for chloride (ECl "), a monovalent anion, can be calculated using the Nernst equation: ECl " (in millivolts) = 61 x log (Ci/Co), where Ci is the intracellular concentration and Co is the extracellular concentration. In this case, ECl " = 61 x log (11/110) = - 61 millivolts.

The table shows the concentrations of four ions across the plasma membrane of a model cell. Refer to this table when answering the following four questions What is the equilibrium potential for Cl- across the plasma membrane of this cell? Select one: a. 122 millivolts b. 0 millivolts c. -122 millivolts d. -61 millivolts e. 61 millivolts

61 millivolts hyperpolarization If a membrane is permeable to only a single ion, Vm is equal to the equilibrium potential for that ion. In this cell, Ek = -61 millivolts. If the extracellular K+ concentration is reduced 10-fold, Ek = 61 x log ((1.4/140) = -122 millivolts, which is a hyperpolarization of 61 millivolts.

The table shows the concentrations of four ions across the plasma membrane of a model cell. Refer to this table when answering the following question If this cell were permeable only to K+, what would be the effect of reducing the extracellular K+ concentration from 14 to 1.4 millimolar? Select one: a. 61 millivolts depolarization b. 122 millivolts depolarization c. 10 millivolts depolarization d. 122 millivolts hyperpolarization e. 61 millivolts hyperpolarization f. 10 millivolts hyperpolarization

partial occlusion of a blood vessel Turbulent flow is predicted when the Reynolds number is increased. Factors that increase the Reynolds number and produce turbulent flow are decreased viscosity (hematocrit) and increased velocity. Partial occlusion of a blood vessel increases the Reynolds number (and turbulence) because the decrease in cross- sectional area results in increased blood velocity (v = Q/A).

The tendency for blood flow to be turbulent is increased by Select one: a. partial occlusion of a blood vessel b. increased viscosity c. increased hematocrit d. decreased velocity of blood flow

filtered load -tubular reabsorption of glucose (TM)

The urinary glucose excretion

myelinating the nerve Myelin insulates the nerve, thereby increasing conduction velocity; action potentials can be generated only at the nodes of Ranvier, where there are breaks in the insulation. Activity of the Na+-K+ pump does not directly affect the formation or conduction of action potentials. Decreasing nerve diameter would increase internal resistance and, therefore, slow the conduction velocity.

The velocity of conduction of action potentials along a nerve will be increased by Select one: a. stimulating the Na+-K+ pump b. myelinating the nerve c. lengthening the nerve fiber d. inhibiting the Na+-K+ pump e. decreasing the diameter of the nerve

hemolytic disease of the newborn •Rh: •Rh ⊝ mothers; Rh ⊕ fetus •First pregnancy: mother exposed to fetal blood (often during delivery) -> formation of maternal anti-D IgG. •Subsequent pregnancies: anti-D IgG crosses the placenta -> HDN in the fetus •Jaundice shortly after birth, kernicterus, hydrops fetalis •Prevent by administration of anti-D IgG to Rh⊝ pregnant women during third trimester and early postpartum period (if fetus tests ⊕ for Rh). Prevents maternal anti-D IgG production. •ABO: •A (B) fetus/O mother •Mother's anti-A (or anti-B) antibodies (IgG !!!) cross the placenta and agglutinize fetal RBCs •Can occur during 1st pregnancy

This disease occurs in the fetus if the fetus is Rh+ while the mother is Rh-.

Blockade of voltage-sensitive Na+ channels, Replacement of the voltage-sensitive K+ channels with "slow" Ca++ channels In the absence of hyperpolarization, the inability of an otherwise excitatory stimulus to initiate an action potential is most likely the result of the blockade of the voltage-gated channels responsible for the generation of the all-or-none depolarization. In nerve cells, these are the voltage-gated Na! channels.

Trace A represents a typical action potential recorded under control conditions from a normal nerve cell in response to a depolarizing stimulus. Which of the following perturbations would account for the failure of the same stimulus to elicit an action potential in trace C Select one: a. Blockade of Na-K "leak" channels b. Blockade of voltage-sensitive K+ channels c. Blockade of voltage-sensitive Na+ channels d. Replacement of the voltage-sensitive Na+ channels with "slow" Ca++ channels e. Replacement of the voltage-sensitive K+ channels with "slow" Ca++ channels

e. Vm, Pna, PK Trace A exhibits the characteristic shape of an action potential, including the rapid depolarizationfollowed by a rapid repolarization that temporarily overshoots the resting potential. Trace B best illustrates the change in PNa that occurs during an action potential. !e rapid increase in PNa closely parallels the rapid depolarization phase of the action potential. Trace C best illustrates the slow onset of the increase in PK that reflects the opening of the voltage-gated K! channels.

Traces A, B, and C in the diagram summarize the changes in membrane potential (Vm) and the underlying membrane permeabilities (P) that occur in a nerve cell over the course of an action potential. Choose the combination of labels below that accurately identifies each of the traces. Select one: a. a b. e c. c d. b e. d

disorders of vascular tone or blood volume, cardiovascular disorders, or cerebrovascular disease. Approximately one-fourth of syncopal episodes are of cardiac origin

Transient decreases in cerebral blood flow are usually due to one of three general mechanisms:

simple diffusion Only two types of transport occur "downhill"—simple and facilitated diffusion. If there is no stereospecificity for the D- or L-isomer, one can conclude that the transport is not carrier-mediated and, therefore, must be simple diffusion.

Transport of D- and L-glucose proceeds at the same rate down an electrochemical gradient by which of the following processes? Select one: a. Countertransport b. Primary active transport c. Cotransport d. Facilitated diffusion e. Simple diffusion

water will move from A to B

Two solutions A and B are separated by a membrane permeable to water. Solution A is 3 mmol/L glycerol, and Solution B is 4 mmol/L NaCl. Assume that g NaCl = 1.85. Which of the following will be correct regarding? Select one: a. there is no water flow between these two solutions b. water will move from A to B c. glycerol will move from A to B until its concentration equalizes in both solutions d. Water will move from B to A e. NaCl will move from B to A until its concentration equalizes in both solutions

A is hyperosmotic and hypertonic

Two solutions A and B are separated from each other by a semipermeable membrane. Solution A is the solution of 3 mol/L NaCl, and B is the solution of 4 mol/L glycerol. Assume that g NaCl = 1.85, that σNaCl = 0.6, and σglycerol = 0.02. Assume that at 37°C (310 K), RT = 25.45 L-atm/mol. Which of the following is correct about these two solutions? Select one: a. A is hyperosmotic and hypertonic b. B is hyperosmotic and hypertonic c. They are isosmotic and isotonic d. They are isotonic, B is hyposmotic, A is hyperosmotic e. They are isosmotic, A is hypotonic, B is hypertonic f. They are isosmotic, B is hypotonic, A is hypertonic g. They are isotonic, A is hyposmotic, B is hyperosmotic h. A is hyperosmotic and hypotonic

500 ml/min Blood flow in a vessel is directly proportional to the fourth power of the vessel radius. Increasing vesseldiameter by 50% (1.5 times control) would increase blood flow 1.5 to the fourth power % normal blood flow (100 ml/min). " us, blood flow would increase to 100 ml/min % 5.06, or approximately 500 ml/min.

Under control conditions, flow through a blood vessel is 100 ml/min with a pressure gradient of 50 mm Hg.What would be the approximate flow through the vessel after increasing the vessel diameter by 50%, assuming the pressure gradient is maintained at 100 mm Hg? Select one: a. 500 ml/min b. 300 ml/min c. 150 ml/min d. 100 ml/min e. 700 ml/min

D Parathyroid hormone (PTH) increases Ca2+ reabsorption from the thick ascending limb and the distal convoluted tubule. Although most of the filtered Ca2+ is reabsorbed in the proximal tubule, the regulation of Ca2+ excretion occurs in the thick ascending limb and the distal convo- luted tubule. PTH regulates the reabsorption of HPO42− in the proximal tubule.

Use the following diagram of a nephron to answer the next questionParathyroid hormone increases Ca2+ reabsorption at which of the following points? Select one: a. A b. B c. C d. D e. E

C THe cephalic phase of gastric secretion is mediated entirely by the vagus nerve: vagotomy abolishes theresponse. "e vagus also mediates a significant portion of the gastric phase of gastric secretion. Vagal stimulation increases acid secretion by a direct action of parietal cells as well as by stimulating gastrin secretion. Vagal stimulation increases gastrin secretion by (a) directly stimulating G cells, which secrete gastrin, and (b) inhibiting somatostatin cells from secreting somatostatin, which would otherwise inhibit G cells from secreting gastrin. Gastrin releasing peptide (GRP) is the neurotransmitter released from interneurons thatstimulate G cells to secrete gastrin.

Vagal stimulation plays an essential role during the cephalic and gastric phases of gastric secretion. Vagal stimulation tends to cause which of the following changes in the release of gastric releasing peptide (GRP) and somatostatin? Select one: a. D b. A c. C d. B e. E

E Essentially all proteolytic enzymes are secreted in an inactive form, which prevents autodigestion of the secreting organ. Enterokinase is physically attached to the brush border of the enterocytes which line the inner surface of the small intestine. Enterokinase activates trypsinogen to become trypsin in the gut lumen. The trypsin then catalyzes the formation of additional trypsin from trypsinogen as well as several other proenzymes (e.g., chymotrypsinogen, procarboxypeptidase, proelastase, and others). Pepsin is first secreted as pepsinogen, which has no proteolytic activity. However, as soon as it comes into contact with hydrochloric acid, and especially in contact with previously formed pepsin plus hydrochloride acid, it is activated to form pepsin.

Various proteolytic enzymes are secreted in an inactive form into the lumen of the gastrointestinal tract. Which of the following substances is/are important for activating one or more proteolytic enzymes, converting them to an active form? Select one: a. E b. B c. A d. D e. C

D The act of vomiting is preceded by antiperistalsis that may begin as far down in the gastrointestinal tract as the ileum. Distension of the upper portions of the gastrointestinal tract (especially the duodenum) becomes the exciting factor that initiates the actual act of vomiting. At the onset of vomiting, strong contractions occur in the duodenum and stomach along with partial relaxation of the lower esophageal sphincter. From then on, a specific vomiting act ensues that involves (a) a deep breath, (b) relaxation of the upper esophageal sphincter, (c) closure of the glottis, and (d) strong contractions of the abdominal muscles and diaphragm.

Vomiting is a complex process that requires coordination of numerous components by the vomiting center located in the medulla. Which of the following occurs during the vomiting act? Select one: a. C b. E c. A d. B e. D

block voltage sensitive Na+ channels and prevent the occurrence of nerve action potentials

What are the actions of the drugs tetrodotoxin and lidocaine?

Bile duct obstruction Most clotting factors are formed in the liver. If a vitamin K injection will correct the problem, this implies that the liver is working fine, and that the patient does not have hepatitis. Vitamin K is a fat-soluble vitamin and is absorbed from the intestine along with fats. Bile secreted by the gallbladder is required for the absorption of fats. If the patient is deficient in vitamin K, then clotting deficiency can be corrected by an injection of vitamin K. Antithrombin II has no relationship to factor IX.

What condition leads to a deficiency in factor IX that can be corrected by an intravenous injection of vitamin K? Select one: a. Classic hemophilia b. Bile duct obstruction c. Genetic deficiency in antithrombin III d. Hepatitis B

Increasing heart rate increases intracellular [Ca2+] because more Ca2+ ions enter the cell during the plateau of each action potential. Sympathetic stimulation and norepinephrine increase intracellular [Ca2+] by increasing entry during the plateau and increasing the storage of Ca2+ by the sarcoplasmic reticulum (SR) [for later release]. Cardiac glycosides increase intracellular [Ca2+] by inhibiting the Na+-K+ pump, thereby inhibiting Na+-Ca2+ exchange (a mechanism that pumps Ca2+ out of the cell).

What increases intracellular Ca2+

38 A 1 millimolar solution has an osmolarity of 1 milliosmole when the solute molecule does not dissociate. However, NaCl and KCl both dissociate into two molecules, and CaCl2 dissociates into three molecules. !erefore, 12 millimolar NaCl has an osmolarity of 24 milliosmoles, 4 millimolar KCl has an osmolarity of 8 milliosmoles, and 2 millimolar CaCl2 has an osmolarity of 6 milliosmoles. !ese add up to 38 milliosmoles.

What is the calculated osmolarity of a solution containing 12 millimolar NaCl, 4 millimolar KCl, and 2 millimolar CaCl2 (in mOsm/L)? Select one: a. 38 b. 26 c. 32 d. 16 e. 29

70 The heart rate can be calculated by 60 divided by the R-R interval, which is 0.86 sec. is results in a heart rate of 70 beats/min.

What is the heart rate in the following EKG? Select one: a. 104 b. 88 c. 94 d. 64 e. 70

-40 mV The normal resting membrane potential of the S-A node is 55 mV. As the sodium leaks into the mem- brane an upward drift of the membrane potential occurs until it reaches 40 mV. is is the threshold level that initiates the action potential at the S-A node

What is the membrane potential (threshold level) at which the S-A node discharges? Select one: a. -105 mV b. -55 mV c. -65 mV d. -85 mV e. -40 mV

Tissue trauma, formation of prothrombin activator, conversion of prothrombin into thrombin, conversion of fibrinogen into fibrin threads the extrinsic pathway involves damage to the tis- sue, then the subsequent formation of prothrombin activator. Tissue trauma results in the release of tissue factor or tissue thromboplastin, which functions as a proteolytic enzyme. Tissue factor binding with factor VII results in an activation of factor X. ere is a subsequent activation of prothrombin activator, con- version of prothrombin to thrombin, then the conver- sion of fibrinogen into fibrin threads. Activation of the extrinsic pathway is very fast because of the small number of enzymatic reactions.

What is the proper pathway for the extrinsic clotting pathway? Select one: a. Trauma to the blood, formation of prothrombin activator, conversion of prothrombin into thrombin, conversion of fibrinogen into fibrin threads b. Activation of platelets, formation of prothrombin activator, conversion of prothrombin into thrombin, conversion of fibrinogen into fibrin threads c. Contact of blood with collagen, formation of prothrombin activator, conversion of prothrombin into thrombin, conversion of fibrinogen into fibrin threads d. Tissue trauma, formation of prothrombin activator, conversion of prothrombin into thrombin, conversion of fibrinogen into fibrin threads

-55 mV The resting membrane potential of the sinus nodal fibers is 55 mV, and this is in contrast with the 85 to 90 mV membrane potential of cardiac muscle. Other major differences between the sinus nodal fibers and ventricular muscle fibers are that the sinus fibers exhibit self-excitation from inward leaking of sodium ions.

What is the resting membrane potential of the sinus nodal fibers? Select one: a. -80 mV b. -55 mV c. -100 mV d. -90 mV e. -20 mV

Bare Zone (H Zone)

What part of the sarcomere changes in length?

Movement of Na+ into the cell (Influx in the cell) (efflux out of the cell) The upstroke of the nerve action potential is caused by opening of the Na+ channels (once the membrane is depolarized to threshold). When the Na+ channels open, Na+ moves into the cell down its electrochemical gradient, driving the membrane potential toward the Na+ equilibrium potential.

What process is responsible for the change in membrane potential that occurs between point 1 and point 3? Select one: a. Movement of K+ into the cell b. Activation of the Na+-K+ pump c. Movement of K+ out of the cell d. Movement of Na+ into the cell e. Movement of Na+ out of the cell

Movement of K+ out of the cell The process responsible for repolarization is the opening of K+ channels. The K+ permeability becomes very high and drives the membrane potential toward the K+ equilibrium potential by flow of K+ out of the cell

What process is responsible for the change in membrane potential that occurs between point 3 and point 4? Select one: a. Movement of K+ into the cell b. Movement of Na+ out of the cell c. Activation of the Na+-K+ pump d. Movement of Na+ into the cell e. Movement of K+ out of the cell

ion channels span the membrane and when open, permit the passage of certain ions

What type of membrane channel has the following characteristics? •selective •may be open or closed •conductance depends on the probability that the channel is open.

facilitated diffusion eg: GLUTs - glucose, galactose, fructose transport

What type of transport has the following characteristics? •down an electrochemical gradient •does not require metabolic energy •more rapid than simple diffusion •is carrier-mediated

primary active transport eg: Na+-K+ pump, Ca2+-ATPase, H+-K+-ATPase

What type of transport has the following characteristics? •against an electrochemical gradient •requires direct input of metabolic energy - ATP •active

secondary active transport

What type of transport has the following characteristics? •two or more solutes is coupled •One of the solutes (Na+) is transported "downhill" and provides energy for the "uphill" transport of the other solute

simple diffusion

What type of transport has the following characteristics? •not carrier-mediated •down an electrochemical gradient •does not require metabolic energy and therefore is passive. •Permeability - describes the ease with which a solute diffuses through a membrane

Between ovulation and the beginning of menstruation the corpus luteum is the only source of progesterone production, except for minute quantities secreted from the follicle before ovulation. e corpus luteum is functional between ovulation and the beginning of menstruation, during which time the concentration of luteinizing hormone (LH) is suppressed below the level achieved during the preovulatory LH surge.

When do progesterone levels rise to their highest point during the female hormonal cycle? Select one: a. Immediately before ovulation b. When 12 primary follicles are developing to the antral stage c. When the blood concentration of luteinizing hormone is at its highest point d. Between ovulation and the beginning of menstruation

left arm By convention, the left arm is the positive elec- trode for lead aVL of an EKG

When recording lead aVL on an EKG, the positive electrode is the Select one: a. right arm + left leg b. left arm + left leg c. right leg d. left arm e. left leg

Increased K+ secretion by the late distal and collecting tubules Most of the daily variation in potassium excretion is caused by changes in potassium secretion in the late distal tubules and collecting tubules. erefore, when the dietary intake of potassium increases, the total body balance of potassium is maintained primarily by an increase in potassium secretion in these tubular segments. Increased potassium intake has little effect on GFR or on reabsorption of potassium in the proxi- mal tubule and loop of Henle. Although high potas- sium intake may cause a slight shift of potassium into the intracellular compartment, a balance between intake and output must be achieved by increasing the excretion of potassium during high potassium intake.

When the dietary intake of K# increases, body K# balance is maintained by an increase in K# excretion primarily by which of the following? Select one: a. Shift of K# into the intracellular compartment b. Decreased reabsorption of K# by the thick ascending limb of the loop of Henle c. Increased K# secretion by the late distal and collecting tubules d. Decreased glomerular filtration of K# e. Decreased reabsorption of K# by the proximal tubule

Blocks Na+-K+ pump indirectly blocks Na+-Ca2+ exchange

Where does the drug digitalis act?

Adrenergic β1 receptors Heart rate is increased by the stimulatory effect of norepineph- rine on β1 receptors in the sinoatrial (SA) node. There are also sympathetic β1 receptors in the heart that regulate contractility.

Which autonomic receptor mediates an increase in heart rate? Select one: a. Cholinergic nicotinic receptors b. Adrenergic β1 receptors c. Cholinergic muscarinic receptors d. Adrenergic β2 receptors e. Adrenergic α receptors

Cholinergic nicotinic receptors Preganglionic sympathetic fibers synapse on the chromaffin cells of the adrenal medulla at a nicotinic receptor. Epinephrine and, to a lesser extent, norepinephrine are released into the circulation.

Which autonomic receptor mediates secretion of epinephrine by the adrenal medulla? Select one: a. Cholinergic nicotinic receptors b. Adrenergic α receptors c. Adrenergic β2 receptors d. Adrenergic β1 receptors e. Cholinergic muscarinic receptors

A there is an antigen and antibody reaction between the anti-A antibodies and the red cells. ere is no reaction between the anti-B antibodies and the red cells. erefore the red cells have the A antigen and the cells must be type A.

Which blood type is depicted in the following figure? Select one: a. A b. AB c. O d. B

A Resistance of a vessel = pressure gradient / blood flow of the vessel. In this example, vessel A has the highest vascular resistance (100 mm Hg/1000 ml/min, or 0.1 mm Hg/ml/min).

Which blood vessel has the highest vascular resistance? Select one: a. C b. D c. A d. B e. E

F Alveolar ventilation can increase by more than eightfold when the arterial carbon dioxide tension is increased over a physiological range from about 35 to 75 mm Hg. is demonstrates the tremendous effect that carbon dioxide changes have in controlling respi- ration. By contrast, the change in respiration caused by changing the blood pH over a normal range from 7.3 to 7.5 is more than 10 times less effective.

Which diagram best describes the relationship between alveolar ventilation (VA) and arterial carbon dioxide tension (PCO%) when the PCO% is changed acutely over a range of 35 to 75 mm Hg? Select one: a. A b. B c. C d. D e. E f. F

Acetylcholine (ACh) Acetylcholine (ACh) has a negative inotropic effect on the atria.

Which of the following agents or changes has a negative inotropic effect on the heart? Select one: a. Norepinephrine b. Acetylcholine (ACh) c. Sympathetic stimulation d. Cardiac glycosides e. Increased heart rate

Cells shrink transiently and return to their original volume over time A solution of 140 millimolar NaCl has an osmolarity of 280 milliosmoles, which is iso-osmotic relative to "normal" intracellular osmolarity. If red blood cells were placed in 140 millimolar NaCl alone, there would be no change in cell volume because intracellular and extracellular osmolarities are equal. !e presence of 20 millimolar urea, however, increases the solution's osmolarity and makes it hypertonic relative to the intracellular solution. Water will initially move out of the cell, but because the plasma membrane is permeable to urea, urea will diffuse into the cell and equilibrate across the plasma membrane. As a result, water will re-enter the cell, and the cell will return to its original volume.

Which of the following best describes the changes in cell volume that will occur when red blood cells (previously equilibrated in a 280-milliosmolar solution of NaCl) are placed in a solution of 140 millimolar NaCl containing 20 millimolar urea, a relatively large but permeant molecule? Select one: a. Cells shrink initially, then swell over time and lyse b. Cells shrink transiently and return to their original volume over time c. No change in cell volume will occur d. Cells swell and lyse e. Cells swell transiently and return to their original volume over time

Cells shrink transiently and return to their original volume over time A solution of 140 millimolar NaCl has an osmolarity of 280 milliosmoles, which is iso-osmotic relative to "normal" intracellular osmolarity. If red blood cells were placed in 140 millimolar NaCl alone, there would be no change in cell volume because intracellular and extracellular osmolarities are equal. !e presence of 20 millimolar urea, however, increases the solution's osmolarity and makes it hypertonic relative to the intracellular solution. Water will initially move out of the cell, but because the plasma membrane is permeable to urea, urea will diffuse into the cell and equilibrate across the plasma membrane. As a result, water will re-enter the cell, and the cell will return to its original volume.

Which of the following best describes the changes in cell volume that will occur when red blood cells (previously equilibrated in a 280-milliosmolar solution of NaCl) are placed in a solution of 140 millimolar NaCl containing 20 millimolar urea, a relatively large but permeant molecule? Select one: a. Cells swell transiently and return to their original volume over time b. Cells shrink transiently and return to their original volume over time c. Cells shrink initially, then swell over time and lyse d. No change in cell volume will occur e. Cells swell and lyse

Type O, Rh +ive packed red cells

Which of the following blood units carries the least risk of inducing an immediate reaction in a type B, Rh+ patient? Select one: a. Type A , Rh+ive whole blood. b. Type AB, Rh -ive packed red cells c. Type O, Rh +ive packed red cells d. Type O, Rh +ive whole blood e. Type AB, Rh +ive whole blood.

Packed red cells O+ In any patient, transfusion of O-type packed cells will minimize a transfusion reaction since the antibodies will be removed with the plasma removal. If the Rh fac- tor is matched, then this will also minimize transfusion reaction. erefore, in a B patient, a B transfusion or an O transfusion will elicit no transfusion reaction.

Which of the following blood units carries the least risks for inducing an immediate transfusion reaction into a B$ (B, rhesus positive) recipient? Select one: a. Whole blood AB+ b. Whole blood A+ c. Packed red cells O+ d. Packed red cells AB- e. Whole blood O+

A decrease in ATP level Rigor is a state of permanent contraction that occurs in skeletal muscle when adenosine triphosphate (ATP) levels are depleted. With no ATP bound, myosin remains attached to actin and the cross-bridge cycle cannot continue. If there were no action potentials in motoneurons, the muscle fibers they innervate would not contract at all, since action potentials are required for release of Ca2+ from the sarcoplasmic reticulum (SR). When intracellular Ca2+ concentration increases, Ca2+ binds troponin C, permitting the cross-bridge cycle to occur. Decreases in intracellular Ca2+ concentration cause relaxation.

Which of the following causes rigor in skeletal muscle? Select one: a. No action potentials in motoneurons b. An increase in adenosine triphosphate (ATP) level c. A decrease in ATP level d. An increase in intracellular Ca2+ level e. A decrease in intracellular Ca2+ level

Increased glomerular capillary filtration coefficient the glomerular capillary filtration coefficient is the product of the hydraulic conductivity and surface area of the glomerular capillaries. Therefore, increasing the glomerular capillary filtration coefficient tends to increase GFR. Increased afferent arteriolar resistance, decreased efferent arteriolar resistance, increased Bowman's capsule hydrostatic pressure, and decreased glomerular hydrostatic pressure tend to decrease GFR

Which of the following changes tends to increase GFR? Select one: a. Decreased glomerular capillary hydrostatic pressure b. Increased afferent arteriolar resistance c. Increased glomerular capillary filtration coefficient d. Decreased efferent arteriolar resistance e. Increased Bowman's capsule hydrostatic pressure

Extracellular fluid volume expansion In the proximal tubule, calcium reabsorption usu- ally parallels sodium and water reabsorption. With extracellular volume expansion or increased blood pressure, proximal sodium and water reabsorption is reduced, and there is also a reduction in calcium reabsorption, causing increased urinary excretion of calcium. Increased parathyroid hormone, increased plasma phosphate concentration, and metabolic acidosis all tend to decrease the renal excretion of calcium.

Which of the following changes tends to increase urinary Ca++ excretion? Select one: a. Metabolic acidosis b. Decreased blood pressure c. Extracellular fluid volume expansion d. Increased plasma parathyroid hormone concentration e. Increased plasma phosphate concentration

D Excessive activity of the amiloride-sensitive so- dium channel in the collecting tubules would cause a transient decrease in sodium excretion and expansion of extracellular fluid volume, which in turn would in- crease arterial pressure and decrease renin secretion, leading to decreased aldosterone secretion. Under steady-state conditions, sodium excretion would return to normal so that intake and renal excretion of sodium are balanced. One of the mechanisms that re-establishes this balance between intake and output of sodium is the rise in arterial pressure that induces a "pressure natriuresis."

Which of the following changes would be expected in a patient with Liddle's syndrome (excessive activity of amiloride-sensitive sodium channel in the collecting tubule) under steady-state conditions, assuming that intake of electrolytes remained constant? Select one: a. A b. B c. C d. D e. E

Increase in plasma reservoir for rapid replenishment of free hormone Protein-bound hormones are biologically inactive and cannot be metabolized. us, an increase in pro- tein binding would tend to decrease hormone activity and plasma clearance and increase the half-life of the hormone. Free hormone is also responsible for nega- tive feedback inhibition of hormone secretion. ere- fore, a sudden increase in hormone binding to plasma proteins would decrease negative feedback. Protein binding of hormones does, however, provide a reser- voir for the rapid replacement of free hormone.

Which of the following changes would be expected to occur with increased binding of a hormone to plasma proteins? Select one: a. Increase in hormone activity b. Increase in plasma clearance of the hormone c. Increase in degree of negative feedback exerted by the hormone d. Increase in plasma reservoir for rapid replenishment of free hormone e. Decrease in half-life of the hormone

E A 50% reduction in renal efferent arteriolar resis- tance would reduce glomerular capillary hydrostatic pressure (upstream from the efferent arterioles) and therefore reduce GFR, while increasing hydrostatic pressure in peritubular capillaries (downstream from the efferent arterioles) and increasing renal blood flow.

Which of the following changes would you expect to find after acute administration of a vasodilator drug that caused a 50% decrease in renal eff erent arteriolar resistance and no change in aff erent arteriolar resistance or arterial pressure? Select one: a. A b. B c. C d. D e. E

Increased renal blood flow, increased GFR, and increased peritubular capillary hydrostatic pressure A 50% reduction in afferent arteriolar resistance with no change in arterial pressure would increase renal blood flow and glomerular hydrostatic pressure, thereby increasing GFR. At the same time, the reduction in afferent arteriolar resistance would raise peritubular capillary hydrostatic pressure.

Which of the following changes would you expect to find after administering a vasodilator drug that caused a 50% decrease in afferent arteriolar resistance and no change in arterial pressure? Select one: a. Increased renal blood flow, increased GFR, and increased peritubular capillary hydrostatic pressure b. Increased renal blood flow, increased GFR, and decreased peritubular capillary hydrostatic pressure c. Decreased renal blood flow, decreased GFR, and decreased peritubular capillary hydrostatic pressure d. Decreased renal blood flow, decreased GFR, and increased peritubular capillary hydrostatic pressure e. Increased renal blood flow, increased GFR, and no change in peritubular capillary hydrostatic pressure

C A plasma glucose concentration of 300 mg/dL would increase the filtered load of glucose above the renal tubular transport maximum and therefore increase uri- nary glucose excretion. e unreabsorbed glucose in the renal tubules would also cause an osmotic diuresis, increased urine volume, and decreased extracellular fluid volume, which would stimulate thirst. Increased glucose also causes vasodilatation of afferent arterioles, which increases GFR

Which of the following changes would you expect to find in a newly diagnosed 10-year-old patient with type I diabetes and uncontrolled hyperglycemia (plasma glucose = 300 mg/dL). Select one: a. A b. B c. C d. D e. E

Occurs down an electrochemical gradient Both types of transport occur down an electrochemical gradient ("downhill"), and do not require metabolic energy. Saturability and inhibition by other sugars are characteristic only of carrier-mediated glucose transport; thus, facilitated diffusion is saturable and inhibited by galactose, whereas simple diffusion is not.

Which of the following characteristics is shared by simple and facilitated diffusion of glucose? Select one: a. Is inhibited by the presence of galactose b. Is saturable c. Requires a Na+ gradient d. Requires metabolic energy e. Occurs down an electrochemical gradient

Veins THe percentage of total blood volume in the veins is approximately 64%.

Which of the following components of the circulatory system contains the largest percentage of the total blood volume? Select one: a. Arteries b. Capillaries c. Pulmonary circulation d. Veins e. Heart

Type A Rh+ packed cells to an O Rh+ patient Type O RBCs are considered to be universal donor blood. Reactions occur between the recipient's antibody and donor antigen as shown in the following table.

Which of the following will result in a transfusion reaction? Assume that the patient has never had a transfusion. Select one: a. Type A Rh+ packed cells to an O Rh+ patient b. Type AB Rh+ packed cells to an AB Rh+ patient c. Type A Rh+ packed cells to an A Rh- patient d. Type O Rh- packed cells to an AB Rh+ patient

Pulmonary hypertension Systemic hypertension results in a left axis devia- tion because of the enlargement of the left ventricle. Aortic valve stenosis and aortic valve regurgitation also result in a large left ventricle and left axis devia- tion. Excessive abdominal fat, because of the mechani- cal pressure of the fat, causes a rotation of the heart to the left resulting in a leftward shift of the mean electri- cal axis. Pulmonary hypertension causes enlargement of the right heart and thus causes right axis deviation.

Which of the following conditions will usually result in right axis deviation in an EKG? Select one: a. Pulmonary hypertension b. Excess abdominal fat c. Aortic valve regurgitation d. Systemic hypertension e. Aortic valve stenosis

Chronic renal failure Ca2+ deficiency (low Ca2+ diet or hypocalcemia) activates 1α-hydroxylase, which catalyzes the conversion of vitamin D to its active form, 1,25-dihy- droxycholecalciferol. Increased parathyroid hormone (PTH) and hypophosphatemia also stimulate the enzyme. Chronic renal failure is associated with a constellation of bone dis- eases, including osteomalacia caused by failure of the diseased renal tissue to produce the active form of vitamin D.

Which of the following decreases the conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol? Select one: a. Hypophosphatemia b. Hyperparathyroidism c. A diet low in Ca2+ d. Chronic renal failure e. Hypocalcemia

F All of these factors can inhibit gastric acid secretion under normal physiological conditions. Gastric acid stimulates the release of somatostatin (a paracrine factor), which has a direct effect on the parietal cell to inhibit acid secretion as well as an indirect effect mediated by suppression of gastrin secretion. Secretin and GLIP inhibit acid secretion through a direct action on parietal cells as well as indirectly through suppression of gastrin secretion. Enterogastrones are unidentified substances released from the duodenum and jejunum that directly inhibit acid secretion. When acid or hypertonic solutions enter the duodenum, a neurally mediated decrease in gastric acid secretion follows.

Which of the following factors can inhibit gastric acid secretion? (GLIP, glucose-dependent insulinotropic peptide) Select one: a. C b. F c. A d. E e. D f. B

E The presence of acid, fatty acids, and hyperosmotic solutions in the duodenum and jejunum lead to suppression of acid secretion through a variety of mechanisms. Acid stimulates the secretion of secretin from the small intestine, which in turn inhibits acid secretion from parietal cells. Acidification of the antrum and oxyntic gland area of the stomach stimulates the release of somatostatin, which in turn inhibits acid secretion by a direct action on the parietal cells and an indirect action mediated by suppression of gastrin secretion. The presence of fatty acids in the small intestine stimulates the release of GLIP (glucose-dependent insulinotropic peptide), which inhibits acid secretion both directly (parietal cell inhibition) and indirectly (by decreasing gastrin secretion). Hyperosmotic solutions in the small intestine cause the release of unidentified enterogastrones, which directly inhibit acid secretion from parietal cells. Isotonic solutions have no effect on acid secretion.

Which of the following factors have a physiologic role to stimulate the release of hormones or stimulate nervous reflexes, which in turn can inhibit gastric acid secretion? Select one: a. E b. A c. D d. C e. B

Increased release of glucose from the liver Because insulin secretion is deficient in type 1 diabetes mellitus, there is increased (not decreased) release of glucose from the liver. Low plasma levels of insulin also lead to a high rate of lipolysis; increased plasma osmolality, hypovolemia, and acidosis are all symptoms of uncontrolled type 1 diabetes mellitus.

Which of the following findings is most likely to occur in a patient who has uncontrolled type 1 diabetes mellitus? Select one: a. Increased plasma pH b. Decreased rate of lipolysis c. Increased plasma volume d. Decreased plasma osmolality e. Increased release of glucose from the liver

Increased synthesis of thyroglobulin Because iodine is needed to synthesize thyroid hormones, the production of thyroid hormones is impaired if iodine is deficient. As a result of feedback, plasma levels of thyroid-stimulating hormone increase and stimulate the follicular cells to increase the synthe- sis of thyroglobulin. is results in a goiter. Increased metabolic rate, sweating, nervousness, and tachycar- dia are all common features of hyperthyroidism, not hypothyroidism due to iodine deficiency

Which of the following findings would likely be reported in a patient with a deficiency in iodine intake? Select one: a. Nervousness b. Tachycardia c. Increased synthesis of thyroglobulin d. Increased sweating e. Weight loss

Total Osmolarity Intracellular and extracellular body fluids have the same total osmolarity under steady-state conditions because the cell membrane is highly permeable to water. erefore, water flows rapidly across the cell membrane until osmotic equilibrium is achieved. e colloid osmotic pressure is determined by the protein concentration, which is considerably higher inside the cell. e cell membrane is also relatively impermeable to potassium, sodium, and chloride, and active trans- port mechanisms maintain low intracellular concen- trations of sodium and chloride and a high intracellu- lar concentration of potassium.

Which of the following has similar values for both intracellular and interstitial body fluids? Select one: a. Potassium ion concentration b. Colloid osmotic pressure c. Chloride ion concentration d. Total osmolarity e. Sodium ion concentration

Gonadotropin-releasing hormone (GnRH) Gonadotropin-releasing hormone (GnRH) is a peptide hor- mone that acts on the cells of the anterior pituitary by an inositol 1,4,5-triphosphate (IP3)-Ca2+ mechanism to cause the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). 1,25-Dihydroxycholecalciferol and progesterone are steroid hormone derivatives of cholesterol that act by inducing the synthesis of new proteins. Insulin acts on its target cells by a tyrosine kinase mechanism. Parathyroid hormone (PTH) acts on its target cells by an adenylate cyclase-cyclic adenosine monophosphate (cAMP) mechanism.

Which of the following hormones acts by an inositol 1,4,5-triphosphate (IP3)-Ca2+ mechanism of action? Select one: a. 1,25-Dihydroxycholecalciferol b. Progesterone c. Gonadotropin-releasing hormone (GnRH) d. Parathyroid hormone (PTH) e. Insulin

Sex steroid Continued production of sex steroid hormones is seen in both 21-hydroxylase and 1ß-hydroxylase deficiency.

___________ hormones are produced in the zona reticularis.

Thyroid hormone Thyroid hormone, an amine, acts on its target tissues by a steroid hormone mechanism, inducing the synthesis of new proteins. The action of antid- iuretic hormone (ADH) on the collecting duct (V2 receptors) is mediated by cyclic adeno- sine monophosphate (cAMP), although the other action of ADH (vascular smooth mus- cle, V1 receptors) is mediated by inositol 1,4,5-triphosphate (IP3). Parathyroid hormone (PTH), β1 agonists, and glucagon all act through cAMP mechanisms of action.

Which of the following hormones acts on its target tissues by a steroid hormone mechanism of action? Select one: a. Glucagon b. Parathyroid hormone (PTH) c. b1 adrenergic agonists d. Antidiuretic hormone (ADH) on the collecting duct e. Thyroid hormone

Growth Hormone GH and ADH are stored in the anterior and poste- rior lobes of the pituitary gland, respectively. However, although GH is also synthesized in the (anterior) pitu- itary gland, this is not the case for ADH. ADH and the hypothalamic releasing (GHRH) and hypothalamic inhibitory hormones (somatostatin) are synthesized in the hypothalamus. Somatomedins are growth factors (small proteins) that stimulate growth in bone and peripheral tissues. One of the most important somato- medins is somatomedin C, which is produced by the liver in response to GH. Somatomedin C stimulates all aspects of bone growth

Which of the following hormones is both synthesized and stored in the pituitary gland? Select one: a. Somatostatin b. GH releasing hormone (GHRH) c. Somatomedin d. Growth hormone (GH) e. ADH

Cholecystokinin (CCK) CCK is the only gastrointestinal hormone that inhibits gastric emptying under physiological conditions. This inhibition of gastric emptying keeps the stomach full for a prolonged time, which is one reason why a breakfast containing fat and protein "sticks with you" better than breakfast meals containing mostly carbohydrates. CCK also has a direct eff ect on the feeding centers of the brain to reduce further eating. Although CCK is the only gastrointestinal hormone that inhibits gastric emptying, all of the gastrointestinal hormones with the exception of gastrin are released to some extent by the presence of fat in the intestine.

Which of the following hormones is released by the presence of fat and protein in the small intestine and has a major effect to decrease gastric emptying? Select one: a. Gastrin b. Glucose-dependent insulinotropic peptide (GLIP) c. Motilin d. Cholecystokinin (CCK)

Thyroid-stimulating hormone (TSH) Thyroid-stimulating hormone (TSH) is secreted by the anterior pituitary. Dopamine, growth hormone-releasing hormone (GHRH), somato- statin, and gonadotropin-releasing hormone (GnRH) all are secreted by the hypothala- mus. Oxytocin is secreted by the posterior pituitary. Testosterone is secreted by the testes.

Which of the following hormones originates in the anterior pituitary? Select one: a. Growth hormone-releasing hormone (GHRH) b. Somatostatin c. Oxytocin d. Gonadotropin-releasing hormone (GnRH) e. Thyroid-stimulating hormone (TSH) f. Dopamine g. Testosterone

Somatomedins Growth hormone is secreted in pulsatile fashion, with a large burst occurring during deep sleep (sleep stage 3 or 4). Growth hormone secretion is increased by sleep, stress, puberty, starvation, and hypoglycemia. Somatomedins are gen- erated when growth hormone acts on its target tissues; they inhibit growth hormone secretion by the anterior pituitary, both directly and indirectly (by stimulating somato- statin release).

Which of the following inhibits the secretion of growth hormone by the anterior pituitary? Select one: a. Starvation b. Hypoglycemia c. Puberty d. Stress e. Sleep f. Somatomedins

the father of the child has to be Rh$ HDN occurs when an Rh mother gives birth to a second Rh child. erefore, the father has to be Rh . e mother becomes sensitized to the Rh anti- gens following the birth of the first Rh child. HDN is prevented by treating the mother with antibodies against Rh antigen after the birth of each Rh child. is will destroy all fetal RBCs in the mother and pre- vent the mother from being sensitized to the Rh anti- gen. A complete blood transfusion of the mother would be required to prevent the formation of Rh antibodies, but this is impractical. A transfusion of the first child after the birth will not accomplish anything as the mother has been exposed to the Rh antigen during the birth process.

Which of the following is TRUE concerning erythroblastosis fetalis (hemolytic disease of the newborn, HDN)? Select one: a. the father of the child has to be Rh$ b. this is prevented by giving the mother a blood transfusion c. A complete blood transfusion after the first birth will prevent HDN d. this occurs when a Rh$ mother has an Rh# child

Generation of action potentials only at the nodes of Ranvier Myelination of the axons of large nerve fibers has several consequences. It provides insulation to the axon membrane, decreasing membrane capacitance and thereby decreasing the "leakage" of ions across the cell membrane. Action potentials in myelinated axons occur only at the periodic breaks in the myelin sheath, called nodes of Ranvier. Voltage-gated Na! channels are concentrated at these nodes. !is arrangement both increases the velocity of the nerve impulses along the axon and minimizes the number of charges that cross the membrane during an impulse, thereby minimizing the energy required by Na, K- ATPase to re-establish the relative concentration gradients for Na and K.

Which of the following is a consequence of myelination in large nerve fibers? Select one: a. Generation of action potentials only at the nodes of Ranvier b. Increased nonselective diffusion of ions across the axon membrane c. Increased membrane capacitance d. Decreased velocity of nerve impulses e. Increased energy requirement to maintain ion gradients

Preganglionic neurons originate in the thoracolumbar spinal cord Sympathetic preganglionic neurons origi- nate in spinal cord segments T1-L3. Thus, the designation is thoracolumbar. The sympa- thetic nervous system is further characterized by short preganglionic neurons that synapse in ganglia located in the paravertebral chain (not in the effector organs) and postganglionic neurons that release norepinephrine (not epinephrine). Common features of the sympathetic and parasympathetic nervous systems are preganglionic neurons that release acetylcholine (ACh) and postganglionic neurons that synapse in effector organs.

Which of the following is a feature of the sympathetic, but not the parasympathetic, nervous system? Select one: a. Postganglionic neurons synapse on effector organs b. Postganglionic neurons release ACh c. Preganglionic neurons release acetylcholine (ACh) d. Ganglia located in the effector organs e. Preganglionic neurons originate in the thoracolumbar spinal cord f. Preganglionic neurons release norepinephrine g. Long preganglionic neurons h. Postganglionic neurons release epinephrine

Vitamin B12 deficiency Vitamin B12 absorption requires intrinsic factor, which is a glycoprotein secreted by parietal cells in the stomach. Binding of intrinsic factor to dietary vitamin B12 is necessary for attachment to specific receptors located in the brush border of the ileum. "erefore, ileal resection can lead to vitamin B12 deficiency. Achalasia is a neuromuscular failure of relaxation at the lower end of the esophagus with progressive dilation, tortuosity, incoordination of peristalsis, and often hypertrophy of the proximal esophagus. Atrophic gastritis is a type of autoimmune gastritis that is mainly confined to the acid-secreting corpus mucosa. The gastritis is diffuse and eventually severe atrophy develops. Ileal resection is likely to cause diarrhea, but not constipation. Benign gastric and duodenal ulcers are best classified together as peptic ulcers even though their etiology is different. In both types of ulcer it is acid and pepsin which causes the mucosal damage. Duodenal ulcers are more common.

Which of the following is a likely consequence of ileal resection? Select one: a. Vitamin B12 deficiency b. Peptic ulcer c. Achalasia d. Constipation e. Atrophic gastritis

Increased blood volume Venous return of the heart is equal to the mean systemic filling pressure minus the right atrial pressure divided by the resistance to venous return. erefore, decreased mean systemic filling pressure will decrease the venous return to the heart. Factors that will decrease the systemic filling pressure include large vein dilation, decreased sympathetic tone, increased venous compliance and increased blood volume.

Which of the following is normally associated with an increased venous return of blood to the heart? Select one: a. Acute large vein dilation b. Decreased mean systemic filling pressure c. Increased blood volume d. Decreased sympathetic tone e. Increased venous compliance

Increased blood volume Venous return of the heart is equal to the mean systemic filling pressure minus the right atrial pressure divided by the resistance to venous return. erefore, decreased mean systemic filling pressure will decrease the venous return to the heart. Factors that will decrease the systemic filling pressure include large vein dilation, decreased sympathetic tone, increased venous compliance and decreased blood volume.

Which of the following is normally associated with an increased venous return of blood to the heart? Select one: a. Increased blood volume b. Acute large vein dilation c. Increased venous compliance d. Decreased mean systemic filling pressure e. Decreased sympathetic tone

Triglycerides Triglycerides are digested within the intestinal lumen to monoglycerides and free fatty acids, which are then absorbed directly through the membrane of the intestinal epithelial cells. After entering the epithelial cell, the fatty acids and monoglycerides are taken up by the cell's smooth endoplasmic reticulum where they are mainly used to form new triglycerides that are subsequently released in the form of chylomicrons through the base of the epithelial cell. The chylomicrons are absorbed by the central lacteal in the villus and transported in lymph through the thoracic lymph duct to the circulating blood. " us, most triglycerides bypass the portal circulation.

Which of the following is not normally found in abundance in the portal blood? Select one: a. Triglycerides b. Amino acids c. Glucose d. Short-chain fatty acids

Movement of K+ out of the cell The rapid depolarization phase is terminated at point D by the inactivation of the voltage-gated Na! channels and the opening of the voltage-gated K! channels. The latter results in the efflux of K! from the cytosol into the extracellular fluid and repolarization of the cell membrane.

Which of the following is primarily responsible for the change in membrane potential between points D and E? Select one: a. Movement of K+ into the cell b. Movement of Na+ out of the cell c. Inhibition of the Na+, K+-ATPase d. Movement of K+ out of the cell e. Movement of Na+ into the cell

Starch The three major sources of carbohydrates in the normal human diet include sucrose mainly from sugarcane and sugar beets, lactose from milk, and a wide variety of large polysaccharides collectively known as starches. Although some diets may contain a large quantity of cellulose, this substance cannot be digested by the human gut and is not considered a food. Maltose is a product of the digestion of starch but is not consumed in large quantities in the human diet.

Which of the following is the main digestible carbohydrate normally consumed in the human diet? Select one: a. Maltose b. Cellulose c. Amylose d. Starch

It spreads inward to all parts of the muscle via the T-tubules Depolarization of the muscle fiber is essential for initiating muscle contraction. The action potential of skeletal muscle is transmitted to all of the fibrils along T-tubules, triggering the release of Ca2+ from the lateral sacs of the sarcoplasmic reticulum next to the T-system. The electrical events in skeletal muscle and the ionic fluxes underlying them are similar to those in nerve. In contrast, the action potential in cardiac muscle is longer and has a prolonged plateau phase.

Which of the following is true regarding the action potential of skeletal muscle? Select one: a. It is longer than the action potential of cardiac muscle b. It has a prolonged plateau phase c. It is not essential for contraction d. It causes the immediate uptake of Ca2+ into the lateral sacs of the sarcoplasmic reticulum e. It spreads inward to all parts of the muscle via the T-tubules

Ascending limb of the loop of Henle The primary site of reabsorption of magnesium is in the loop of Henle, where about 65% of the filtered load of magnesium is reabsorbed. e proximal tubule normally reabsorbs only about 25% of filtered magne- sium, and the distal and collecting tubules reabsorb less than 5%.

Which of the following nephron segments is the primary site of magnesium reabsorption under normal conditions? Select one: a. Descending limb of the loop of Henle b. Proximal tubule c. Collecting ducts d. Distal convoluted tubule e. Ascending limb of the loop of Henle

B With carbon monoxide there is only a small change in CO required to bind to hemoglobin. erefore there is a minimal change in PO2. us, there will be no stimu- lus to increase respiration, and thus no change in PCO2.

Which of the following occurs with carbon monoxide inhalation? Select one: a. A b. B c. C d. D e. E f. F

E Carbon monoxide (CO) combines with hemoglobin at the same point on the hemoglobin molecule as oxygen and therefore can displace oxygen from the hemoglobin, reducing the oxygen saturation of hemo- globin. Because CO binds with hemoglobin (to form carboxyhemoglobin) with about 250 times as much te- nacity as oxygen, even small amounts of CO in the blood can severely limit the oxygen carrying capacity of the blood. e presence of carboxyhemoglobin also shifts the oxygen dissociation curve to the left (which means that oxygen binds more tightly to hemoglobin), which further limits the transfer of oxygen to the tissues.

Which of the following oxygen-hemoglobin dissociation curves corresponds to normal blood (red line) and blood containing carbon monoxide (green line)? Select one: a. A b. B c. C d. D e. E f. F

e. Glycerol and urea are both permeant molecules, which means that both will diffuse through the cell membrane until the intracellular and extracellular concentrations are identical. !us, during steady-state conditions the intracellular and extracellular osmolarity is 600 mOsm/L (300 mOsm/L from urea and 300 mOsm/L from glycerol). Choice A is not correct because albumin is a smaller molecule compared to IgG. !is difference in molecular weight means that a 10% solution of albumin will contain more molecules per unit volume compared to a 10% solution of IgG and thus exert a greater osmotic effect. Choice B: A solution of 100 mmol/L NaCl has an osmolarity of 200 mOsm/L because Na and Cl dissociate. !us, the osmolarity of solution A will be two times greater than solution B. Choices C and D: Both solutions have equal osmolarities; however, both urea and glycerol are permeant molecules (whereas glucose and NaCl are not), which means that urea and glycerol will diffuse into the cell and effectively cancel their osmotic effects across the cell membrane.

Which of the following pairs of aqueous solutions will exert equal osmotic pressures across a normal cell membrane once steady-state conditions have been established? Select one: a. b b. e c. d d. a e. c

Veins The vascular compliance is proportional to the vascular distensibility and vascular volume of any given segment of the circulation. e compliance of a systemic vein is 24 times that of its corresponding artery because it is about 8 times as distensible and it has a volume about 3 times as great.

Which of the following parts of the circulation has the highest compliance? Select one: a. Veins b. Large arteries c. Capillaries d. Aorta e. Small arteries

aorta THe velocity of blood flow within each segment of the circulatory system is inversely proportional to the total cross-sectional area of the segment. Because the aorta has the smallest total cross-sectional area of all circulatory segments, it has the highest velocity of blood flow.

Which of the following segments of the circulatory system has the highest velocity of blood flow? Select one: a. Veins b. Venules c. Aorta d. Arteries e. Capillaries

F THe pulmonary and systemic circulations both receive about the same amount of blood flow because the lungs receive the entire cardiac output. [However, the output of the left ventricle is actually 1% to 2% higher than the right ventricle because the bron- chial arterial blood originates from the left ventricle and the bronchial venous blood empties into the pul- monary veins.] e pulmonary blood vessels have a relatively low resistance allowing the entire cardiac output to pass through them without increasing the pressure to a great extent. e pulmonary artery pressure averages about 15 mm Hg, which is much lower than the systemic arterial pressure of about 100 mm Hg.

Which of the following sets of diff erences best describes the hemodynamics of the pulmonary circulation when compared to the system circulation? Select one: a. A b. B c. C d. D e. E f. F

C THe adult form of excess growth hormone secre- tion is called acromegaly and is usually associated with a pituitary tumor. Increased plasma levels of growth hormone stimulate the liver and other tissues to produce somatomedin C. As a result of feedback, increased plasma levels of somatomedin C cause the hypothalamus to increase the secretion of growth hormone-inhibiting hormone, somatostatin. Elevated plasma levels of growth hormone also tend to in- crease plasma glucose concentration, which favors an increase in insulin secretion.

Which of the following sets of physiological changes is most likely to occur in a patient in the early stages of acromegaly? Select one: a. D b. C c. A d. B e. E

1 L of 3% sodium chloride solution A 3% sodium chloride (NaCl) solution is hyper- tonic and when infused intravenously would increase extracellular fluid volume and osmolarity, thereby causing water to flow out of the cell. is would decrease intracellular fluid volume and further increase extracellular fluid volume. e 0.9% NaCl solution and 5% dextrose solution are isotonic, and therefore would not reduce intracellular fluid volume. Pure water and the 0.45% NaCl solution are hypotonic, and when infused would increase both intracellular and extracellular fluid volumes.

Which of the following solutions when infused intravenously would result in an increase in extracellular fluid volume, a decrease in intracellular fluid volume, and an increase in total body water after osmotic equilibrium? Select one: a. 1 L of 5% dextrose solution b. 1 L of 3% sodium chloride solution c. 1 L of 0.45% sodium chloride solution d. 1 L of 0.9% sodium chloride solution e. 1 L of pure water

It has opposite effects on urine and plasma osmolality Antidiuretic hormone (ADH) increases the perme- ability of the collecting tubules and ducts to water, but not to sodium, which in turn increases water reabsorp- tion and decreases water excretion. As a result, urine concentration increases, and the retained water dilutes the plasma. ADH is synthesized in the supraoptic and paraventricular nuclei of the hypothalamus and has no direct effect on the thirst center.

Which of the following statements about antidiuretic hormone is true? Select one: a. It is synthesized in the posterior pituitary gland b. It has opposite effects on urine and plasma osmolality c. It stimulates thirst d. It increases salt and water reabsorption in the collecting tubules and ducts

C Acid acts directly on somatostatin cells to stimulate the release of somatostatin. " e somatostatin decreases acid secretion by directly inhibiting the acid secreting parietal cells and indirectly by inhibiting gastrin secretion from G cells in the antrum. Acid is a weak stimulus for CCK release, but CCK does not inhibit (or stimulate) gastrin release. Acid does not stimulate GLIP release. Fatty acids are a weak stimulus for motilin, but motilin does not aff ect gastrin release. Fatty acids are not thought to stimulate somatostatin release.

Which of the following stimulus-mediator pairs normally inhibit gastrin release? (CCK, cholecystokinin; GLIP, glucose-dependent insulinotropic peptide) Select one: a. C b. B c. A d. E e. D

Orad stomach During a swallow, the orad portion of the stomach and lower esophageal sphincter relax at about the same time. Intraluminal pressures in both regions decrease before the arrival of the swallowed bolus. THis phenomenon is called receptive relaxation. Because the orad stomach relaxes with each swallow, the stomachcan accept a large volume of food with only a few mm Hg rise in intragastric pressure. Receptive relaxation is mediated by aff erent and eff erent pathways in the vagus. Receptive relaxation and gastric distensibility are impaired following vagotomy. THe palatopharyngeal folds are important for determining whether abolus of food is small enough to be swallowed. THe pharynx and thoracic esophagus undergo peristaltic contractions during swallowing, but they do not undergo receptive relaxation. THe upper esophagealsphincter opens during a swallow, but this is not considered to be receptive relaxation.

Which of the following structures undergoes receptive relaxation when a bolus of food is swallowed? Select one: a. Thoracic esophagus b. Orad stomach c. Palatopharyngeal folds d. Upper esophageal sphincter e. Pharynx

Glucose Because O2, CO2, and CO are lipophilic, they cross capillary walls primarily by diffusion through the endothelial cell membranes. Glucose is water- soluble; it cannot cross through the lipid component of the cell membrane and is restrict- ed to the water-filled clefts, or pores, between the cells.

Which of the following substances crosses capillary walls primarily through water-filled clefts between the endothelial cells? Select one: a. CO2 b. CO c. Glucose d. O2

Adrenocorticotropic hormone (ACTH) Pro-opiomelanocortin (POMC) is the parent molecule in the anterior pituitary for adrenocorticotropic hormone (ACTH), β-endorphin, α-lipotropin, and β-lipotropin [and in the intermediary lobe for melanocyte-stimulating hormone (MSH)]. Follicle-stimulating hormone (FSH) is not a member of this "family"; rather, it is a member of the thyroid-stimulating hormone (TSH) and luteinizing hormone (LH) "family." MSH, a component of POMC and ACTH, may stimulate melatonin produc- tion. Cortisol and dehydroepiandrosterone are produced by the adrenal cortex.

Which of the following substances is derived from pro-opiomelanocortin (POMC)? Select one: a. Follicle-stimulating hormone (FSH) b. Melatonin c. Cortisol d. Adrenocorticotropic hormone (ACTH) e. Dehydroepiandrosterone

Inulin and radioactive albumin Interstitial fluid volume is measured indirectly by determining the difference between extracellular fluid (ECF) volume and plasma volume. Inulin, a large fructose polymer that is restricted to the extracellular space, is a marker for ECF vol- ume. Radioactive albumin is a marker for plasma volume.

Which of the following substances or combinations of substances could be used to measure interstitial fluid volume? Select one: a. D2O alone b. Inulin and D2O c. Evans blue d. Mannitol e. Inulin and radioactive albumin

Creatinine Sodium is isosmotically reabsorbed from the proximal tubule; that is, when sodium is reabsorbed, water flows out of the proximal tubule to maintain a constant osmolarity. Thus, the concentration of sodium does not normally change as the filtrate flows through the proximal tubule. Because creatinine cannot be reab- sorbed from the tubule, its concentration rises as water is reabsorbed. The concentration of glucose, bicarbonate, and phosphate are all less at the end of the proximal tubule than at the beginning.

Which of the following substances will be more concentrated at the end of the proximal tubule than at the beginning of the proximal tubule? Select one: a. Phosphate b. Glucose c. Bicarbonate d. Sodium e. Creatinine

A diuretic that inhibits the action of aldosterone (e.g., spironolactone) Aldosterone stimulates potassium secretion by the principal cells of the collecting tubules. erefore, blockade of the action of aldosterone with spironolac- tone would inhibit potassium secretion. Other factors that stimulate potassium secretion by the cortical collecting tubule include increased potassium concen- tration, increased cortical collecting tubule flow rate (as would occur with high sodium intake or a diuretic that reduces proximal tubular sodium reabsorption), and acute alkalosis.

Which of the following tends to decrease potassium secretion by the cortical collecting tubule? Select one: a. A diuretic that decreases proximal tubule sodium reabsorption b. Increased plasma potassium concentration c. High sodium intake d. Acute alkalosis e. A diuretic that inhibits the action of aldosterone (e.g., spironolactone)

A Rh- whole blood to a B Rh- patient Transfusion of Rh blood into a Rh person with the same ABO type will not result in any reaction. Type A blood has A antigen on the surface and type B antibodies. Type B blood has B antigens and A anti- bodies. erefore, transfusing A blood into a person with type B blood will cause the A antibodies in the type B person to react with the donor blood.

Which of the following transfusions will result in an immediate transfusion reaction? Select one: a. O Rh+ whole blood to an O Rh- patient b. AB Rh- whole blood to an AB Rh+ patient c. A Rh- whole blood to a B Rh- patient d. B Rh whole blood to an B Rh- patient

cotransport In the "usual" Na+ gradient, the [Na+] is higher in extracellular than in intracellular fluid (maintained by the Na+-K+ pump). Two forms of transport are energized by this Na+ gradient—cotransport and countertransport. Because glucose is moving in the same direction as Na+, one can conclude that it is cotransport

Which of the following transport processes is involved if transport of glucose from the intestinal lumen into a small intestinal cell is inhibited by abolishing the usual Na+ gradient across the cell membrane? Select one: a. Countertransport b. Cotransport c. Simple diffusion d. Primary active transport e. Facilitated diffusion

Capillaries The capillaries have the largest total cross- sectional area of all vessels of the circulatory system. e venules also have a relatively large total cross- sectional area, but not as great as the capillaries, which explains the large storage of blood in the venous sys- tem compared with that in the arterial system.

Which of the following vessels has the greatest total cross-sectional area in the circulatory system? Select one: a. Small arteries b. Venules c. Capillaries d. Aorta e. Vena cava

Doubling the oil/water partition coefficient of the solute Increasing oil/water partition coefficient increases solubility in a lipid bilayer and therefore increases permeability. Increasing molecular radius and increased membrane thickness decrease permeability. The concentration difference of the solute has no effect on permeability.

Which of the following will double the permeability of a solute in a lipid bilayer? Select one: a. Doubling the oil/water partition coefficient of the solute b. Doubling the thickness of the bilayer c. Doubling the molecular radius of the solute d. Doubling the concentration difference of the solute across the bilayer

Increased triiodothyronine (T3) levels Graves' disease (hyperthyroidism) is caused byover- stimulation of the thyroid gland by circulating antibodies to the thyroid-stimulating BRS Physiology hormone (TSH) receptor [which then increases the production and secretion of tri- iodothyronine (T3) and thyroxine (T4), just as TSH would]. Therefore, the signs and symp- toms of Graves' disease are the same as those of hyperthyroidism, reflecting the actions of increased circulating levels of thyroid hormones: increased heat production, weight loss, increased O2 consumption and cardiac output, exophthalmos (bulging eyes, not drooping eyelids), and hypertrophy of the thyroid gland (goiter). TSH levels will be decreased (not increased) as a result of the negative feedback effect of increased T3 levels on the anterior pituitary.

Which of the following would be expected in a patient with Graves' disease? Select one: a. Atrophy of the thyroid gland b. Decreased cardiac output c. Increased thyroid-stimulating hormone (TSH) levels d. Drooping eyelids e. Weight gain f. Decreased O2 consumption g. Increased triiodothyronine (T3) levels h. Cold sensitivity

Hyperpolarizing the membrane potential The amount of potassium leaking out of the cell depends on its membrane potential, its concentration gradient, and its membrane conductance. According to the Nernst equation, the electrical gradient for K+ is inward and the concentration gradient is outward. Hyperpolarizing the membrane makes the inside of the cell morenegative and therefore makes it more difficult for potassium to flow out of the cell. Decreasing the extracellular potassium concentration would increase the flow of potassium out of the cell, as would increasing the permeability of the membrane to potassium. Altering the activity of the sodium-potassium pump or the extracellular sodium concentration has no immediate effect on the flow of potassium across the membrane. Decreasing the activity of the sodium-potassium pump will ultimately depolarize the membrane, however, resulting in an increased flow of potassium out of the cell.

Which of the following would cause an immediate reduction in the amount of potassium leaking out of a cell? Select one: a. Hyperpolarizing the membrane potential b. Reducing the activity of the sodium-potassium pump c. Increasing the permeability of the membrane to potassium d. Decreasing the extracellular potassium concentration e. Decreasing the extracellular sodium concentration

Chronic treatment with a diuretic that inhibits the action of aldosterone Inhibition of aldosterone causes hyperkalemia by two mechanisms: (1) shifting potassium out of the cells into the extracellular fluid, and (2) decreasing cortical collecting tubular secretion of potassium. In- creasing potassium intake from 60 to 180 mmol/day would cause only a very small increase in plasma potassium concentration in a person with normal kid- neys and normal aldosterone feedback mechanisms (see TMP11 Figures 29-7 and 29-8). A reduction in sodium intake also has very little effect on plasma potassium concentration. Chronic treatment with a diuretic that inhibits loop of Henle Na -2Cl -K co-transport would tend to cause potassium loss in the urine and hypokalemia. However, chronic treatment with a diuretic that inhibits sodium reabsorption in the collecting ducts, such as amiloride, would have little effect on plasma potassium concentration.

Which of the following would cause the greatest degree of hyperkalemia? Select one: a. Chronic treatment with a diuretic that inhibits sodium reabsorption in the collecting ducts b. Chronic treatment with a diuretic that inhibits loop of Henle Na#-2Cl"-K# co-transport c. Increase in potassium intake from 60 to 180 mmol/ day in a person with normal kidneys and a normal aldosterone system d. Chronic treatment with a diuretic that inhibits the action of aldosterone e. Decrease in sodium intake from 200 to 100 mmol/ day

Movement of leg muscles Interstitial hydrostatic pressure in a muscle capil- lary bed is normally negative ( 3 mm Hg). Pumping by the lymphatic system is the basic cause of the nega- tive pressure.

Which of the following would decrease venous hydrostatic pressure in the legs? Select one: a. Presence of ascitic fluid in the abdomen b. Pregnancy c. Increase in right atrial pressure d. Movement of leg muscles

Excessive antidiuretic hormone secretion Excessive secretion of antidiuretic hormone increases water reabsorption by the renal collecting tubules, which reduces extracellular fluid sodium con- centration (hyponatremia). Restriction of fluid intake, excessive aldosterone secretion, or administration of hypertonic 3% NaCl solution would all cause increased plasma sodium concentration (hypernatremia), whereas administration of 0.9% NaCl (an isotonic solution) would cause no major changes in plasma osmolarity.

Which of the following would likely lead to hyponatremia? Select one: a. Administration of 2 L of 0.9% sodium chloride solution b. Restriction of fluid intake c. Administration of 2 L of 3% sodium chloride solution d. Excess aldosterone secretion e. Excessive antidiuretic hormone secretion

Aspirin Heparin is used for the prevention of a clot, but has to be infused. is occurs by binding to antithrom- bin III and the subsequent inactivation of thrombin. Warfarin is used to inhibit the formation of vitamin K clotting factors. Aspirin is used to prevent activation of platelets. Activation of platelets following exposure to an atherosclerotic plaque and the formation of a platelet plug will impede blood flow and result in an ischemic heart attack. Streptokinase is used to break down an already formed clot, which is appropriate therapy for a pulmonary embolus

Which of the following would most likely be used for prophylaxis of transient ischemic heart attack? Select one: a. Streptokinase b. Aspirin c. Heparin d. Warfarin

Aspirin Heparin is used for the prevention of a clot, but has to be infused. is occurs by binding to antithrom- bin III and the subsequent inactivation of thrombin. Warfarin is used to inhibit the formation of vitamin K clotting factors. Aspirin is used to prevent activation of platelets. Activation of platelets following exposure to an atherosclerotic plaque and the formation of a platelet plug will impede blood flow and result in an ischemic heart attack. Streptokinase is used to break down an already formed clot, which is appropriate therapy for a pulmonary embolus

Which of the following would most likely be used for prophylaxis of transient ischemic heart attack? Select one: a. Streptokinase b. Aspirin c. Warfarin d. Heparin

Increased intracellular Ca2+ concentration Inhibition of Na+,K+-adenosine triphosphatase (ATPase) leads to an increase in intracellular Na+ concentration. Increased intracellular Na+ concentration decreases the Na+ gradient across the cell membrane, thereby inhibiting Na+-Ca2+ exchange and causing an increase in intracellular Ca2+ concentration. Increased intracellular Na+ concentration also inhibits Na+-glucose cotransport.

Which of the following would occur as a result of the inhibition of Na+, K+-ATPase? Select one: a. Increased Na+-glucose cotransport b. Increased Na+-Ca2+ exchange c. Increased intracellular Ca2+ concentration d. Decreased intracellular Na+ concentration e. Increased intracellular K+ concentration

increased filtration fraction Increasing filtration fraction means that a larger portion of the renal plasma flow (RPF) is filtered across the glomerular capillaries. This increased flow causes an increase in the protein concentration and oncotic pressure of the blood leaving the glomerular capillaries. This blood becomes the peritubular capillary blood supply. The increased oncotic pressure in the peritubular capillary blood is a driving force favoring reabsorption in the proximal tubule. Extracellular fluid (ECF) volume expan- sion, decreased peritubular capillary protein concentration, and increased peritubular capillary hydrostatic pressure all inhibit proximal reabsorption. Oxygen deprivation would also inhibit reabsorption by stopping the Na+-K+ pump in the basolateral membranes.

Which of the following would produce an increase in the reabsorption of isosmotic fluid in the proximal tubule? Select one: a. Extracellular fluid (ECF) volume expansion b. Increased peritubular capillary hydrostatic pressure c. Increased filtration fraction d. Oxygen deprivation e. Decreased peritubular capillary protein concentration

C Trace C shows a basal subatmospheric pressure with a positive pressure wave cause by passage of the food bolus. Trace A shows an increase LES pressure after swallowing. Trace B could represent the lower esophageal sphincter (LES) in a patient with achalasia. Trace D depicts normal operation of the LES. Trace E show a basal positive pressure trace, which does not occur where the esophagus passes through the chest cavity

Which one of the following manometric recordings illustrate normal function of the esophagus at midthoracic level before and after swallowing (indicated by arrow)? The dashed lines represent a pressure of 0 mm Hg Select one: a. D b. C c. B d. E e. A

E Aplastic anemia is a condition in which the bone marrow has a decreased production but does not respond to erythropoietin. erefore, a person with aplastic anemia would have a low hematocrit and an elevated erythropoietin level.

Which points in the following graph most closely define Aplastic anemia? Normal erythropoietin (EPO) levels are approximately 10. Select one: a. A b. E c. D d. C e. B

D A well-trained athlete will have a slightly elevated EPO level and the hematocrit will be elevated up to a value of 50%. A hematocrit higher than 50% suggests EPO treatment.

Which points in the following graph most closely define Olympic marathoner? Normal erythropoietin (EPO) levels are approximately 10. Select one: a. C b. D c. B d. A e. E

α1 Receptors The α1 receptors for norepinephrine are excitatory on vascular smooth muscle and cause vasoconstriction. There are also β2 receptors on the arterioles of skeletal muscle, but they produce vasodilation.

Which receptor mediates constriction of arteriolar smooth muscle? Select one: a. b1 Receptors b. b2 Receptors c. a1 Receptors d. Muscarinic receptors

Cholesterol -> pregnenolone The conversion of cholesterol to pregnenolone is catalyzed by cholesterol desmolase. This step in the biosynthetic pathway for steroid hormones is stimulated by adrenocorticotropic hormone (ACTH).

Which step in steroid hormone biosynthesis is stimulated by adrenocorticotropic hormone (ACTH)? Select one: a. Progesterone -> 11-deoxycorticosterone b. Cholesterol -> pregnenolone c. Testosterone -> dihydrotestosterone d. Testosterone -> estradiol e. 17-Hydroxypregnenolone -> dehydroepiandrosterone

17-Hydroxypregnenolone -> dehydroepiandrosterone The conversion of 17-hydroxypregnenolone to dehydroepiandrosterone (as well as the conversion of 17-hydroxyprogesterone to androstene- dione) is catalyzed by 17,20-lyase. If this process is inhibited, synthesis of androgens is stopped.

Which step in steroid hormone biosynthesis,if inhibited, blocks the production ofall androgenic compounds but does not block the production of glucocorticoids? Select one: a. Testosterone - estradiol b. Testosterone -> dihydrotestosterone c. Cholesterol -> pregnenolone d. 17-Hydroxypregnenolone -> dehydroepiandrosterone e. Progesterone -> 11-deoxycorticosterone

Vitamin K deficiency the clotting factors are formed in the liver and require vitamin K. Vitamin K is a fat-soluble vitamin and absorption is dependent on adequate fat digestion and absorption. erefore, any state of malnutrition would have a decreased fat absorption, and results in decreased vitamin K absorption and decreased syn- thesis of clotting factors.

Why do some malnourished patients bleed excessively when injured? Select one: a. Platelet sequestration by fatty liver b. Serum bilirubin raises neutralizing thrombin c. Low serum-protein levels cause factor XIII problems d. Vitamin K deficiency

C Diuretics that inhibit loop of Henle sodium reab- sorption are used to treat conditions associated with excessive fluid volume (e.g., hypertension and heart failure). ese diuretics initially cause an increase in sodium excretion that reduces extracellular fluid volume and blood pressure, but under steady-state conditions, the urinary sodium excretion returns to normal, due in part to the fall in blood pressure. One of the important side effects of loop diuretics is hypo- kalemia that is caused by the inhibition of Na -2Cl -K co-transport in the loop of Henle and by the increased tubular flow rate in the cortical collecting tubules, which stimulates potassium secretion.

You begin treating a hypertensive patient with a powerful loop diuretic (e.g., furosemide). Which of the following changes would you expect to find, compared with pretreatment values, when he returns for a follow-up examination 2 weeks later? Select one: a. A b. B c. C d. D e. E

E A 50% reduction in GFR (from 80 to 40 ml/min) would result in an approximate 50% reduction in creatinine clearance rate, since creatinine clearance is approximately equal to the GFR. is would, in turn, lead to doubling of plasma creatinine concentration. is rise in plasma creatinine concentration results from an initial decrease in creatinine excretion rate, but as the plasma creatinine concentration increases, the filtered load of creatinine (the product of GFR plasma creatinine concentration) returns to normal and creatinine excretion rate returns to normal un- der steady-state conditions. us, under the steady state conditions, a 50% reduction in GFR is associ- ated with a doubling of plasma creatinine concentra- tion, a 50% decrease in creatinine clearance, a normal filtered load of creatinine, as well as no change in load of filtered creatinine and no change in creatinine excretion rate as long as the person's protein metabo- lism is not altered. Likewise, sodium excretion rate returns to normal even when the GFR is reduced because of multiple feedback systems that eventually reestablish sodium balance. Under steady-state con- ditions sodium excretion must equal sodium intake in order to maintain life.

You have been following a patient with type 2 diabetes and chronic renal disease and his GFR has decreased from 80 ml/min to 40 ml/min over the past 4 years. Which of the following changes would you expect to find compared to 4 years ago, before the decline in GFR, assuming steady-state conditions and no change in electrolyte intake or protein metabolism? Select one: a. A b. B c. C d. D e. E f. F

Fanconi syndrome

a decrease in Na+ transport out of the cells by Na+-K+ ATPase

Hypokalemia

a decrease in extracellular potassium hyperpolarizes the cell (RMP is more negative) and increases the size of action potential

Hemophilia

a genetic loss of clotting factor VIII

Erythropoietin

a glycoprotein hormone that is secreted from the interstitial cells of the kidney to increase RBC production. Upon erythropoietin binding to its receptor (EpoR), intracellular nonreceptor tyrosine kinases transduce signals via the JAK-STAT pathway.

Tachycardia

a heart rate above 100 beats per minute

action potential

a phenomenon of excitable cells such as nerve and muscle and consists of rapid changes in the membrane potential that spread rapidly along a membrane

BNP, or brain natriuretic peptide

a polypeptide secreted by the ventricles of the heart to decrease systemic vascular resistance and central venous pressure, in the setting of heart failure. Upon BNP binding to its receptors (NPRA), the intracellular cGMP-signaling cascade is activated to mediate vasodilation.

distal convoluted tubule

a portion of kidney nephron between the loop of Henle and the collecting duct system.

Hyperosmotic

a solution with the higher osmolarity that another one?

Hyposmotic

a solution with the lower osmolarity of the other one?

Cortisol

a steroid hormone secreted from the zona fasciculata of the adrenal cortex. Upon cortisol binding to intracellular glucocorticoid receptor, it undergoes nuclear translocation to regulate gene expression.

ACTH

an endocrine hormone secreted from the anterior pituitary gland that stimulates glucocorticoid steroid hormone secretion from the adrenal cortex. Upon ACTH binding to cell surface ACTH receptor, the intracellular cAMP-signaling cascade is activated to mediate secretion of glucocorticoid steroid.

87. A 42-year-old man comes to the physician because of a 3-year history of abdominal discomfort. He takes no medications or dietary supplements. Upper Endoscopy shows a 1-cm, benight ulcer crater on the lesser curvature of the stomach. Cultures grow helicobacter pylori. Tissue sam;ing from the gastric Antrum showed a 95% decrease in parietal cell density. Long-term decrease cells is most likely to cause which of the following conditions?

anemia

G-protein-coupled receptors (GPCRs)

are located on the cell's surface. Although literature shows evidence that steroid hormones may bind to GPCRs, this is not the major mechanism by which they modulate gene expression

37. A 37-year-old woman is brought to the emergency department after her husband found her unconscious. Her temperature is 36 C (96.8F), pulse is 128/min, and blood pressure is 70/40 mm Hg. PHysical examination shows cool, pale extremities, jugular venous distention, feint peripheral pulses and crackles over the bottom two thirds of both lung fields. Heart sounds are normal, and there are no murmurs. She withdraws to painful stimuli in all four extremities. This patient is most likely experiencing which of the following types of shock?

cardiogenic

Phagocytosis

cells bind and internalize particulate matter larger than around 0.75 µm in diameter, such as small-sized dust particles, cell debris, micro-organisms and apoptotic cells

Sinus Bradycardia

characterized by normal sinus rhythm, with a P wave before every QRS, and a ventricular rate < 60 beats per minute (bpm). This can be normal for some individuals or can result from medications like calcium channel blockers or beta blockers. Some individuals may be asymptomatic if their baseline is < 60 bpm, while others may develop dizziness, syncope, and hypotension.

Mobitz type I

characterized by progressive PR interval lengthening, until a beat is "dropped," indicating that the depolarization signal failed to pass from the atria to the ventricles. It is usually asymptomatic and is often caused by medications such as digoxin, calcium channel blockers, and beta-blockers. It can also be caused by right-sided heart ischemia. It is treated by stopping the medication, although atropine is sometimes used

The QR segment

corresponds to ventricular depolarization, which is Phase 0 of the myocyte action potential and is characterized by sodium influx.

Tropomyosin

covers myosin binding sites on the actin molecules

Excitatory postsynaptic potentials (EPSPs)

depolarize the postsynaptic cell •opening Na+ and K+ channels

•Lung compliance describes the change in lung volume for a given change in pressure. •The compliance of the lungs and chest wall is inversely correlated with their elastic properties or elastance •expressed as ΔV/ΔP and is inversely proportional to wall stiffness. •High compliance = lung easier to fill (emphysema, normal aging), •lower compliance = lung harder to fill (pulmonary fibrosis, pneumonia, NRDS, pulmonary edema). •Surfactant increases compliance. •At FRC, inward pull of lung is balanced by outward pull of chest wall, and system pressure is atmospheric.

describe lung compliance

1. Depolarization of smooth muscle opens voltage-gated Ca2+ channels in the sarcolemmal membrane. 2. Ca2+ binds to calmodulin 4 A. The Ca2+ -calmodulin complex binds to and activates myosin-light-chain kinase (phosphorylation of myosin light chain) 4 B. Ca2+ -calmodulin complex affects two thin filament proteins - calponin and caldesmon 5. cross-bridge cycling 6. Relaxation - intracellular Ca2+ concentration falls or activation of myosin-light-chain phosphatase

describe smooth muscle contraction

Mobitz Type II heart block

diagnosed by unexpected, randomly dropped beats without lengthening or change in the PR interval. It is caused by fibrotic disease of the cardiac electrical conduction system, often as an acute or chronic complication of a myocardial infarction. It is symptomatic with occasional syncope and frequently progresses to third degree heart block. Therefore, pacemaker placement is indicated.

6. A 16-year-old type 1 diabetic is noncompliant with his required insulin therapy and develops hyperglycemia after eating several pieces of hard candy. The Release of which of the following intestinal hormones would most likely be stimulated in response to oral glucose intake?

gastric inhibitory peptide [GIP]

hemophilias

hereditary bleeding disorders caused by lack of clotting factors Symptoms include prolonged bleeding and painful and disabled joints

respiratory alkalosis

high pH, low CO2

Inhibitory postsynaptic potentials (IPSPs)

hyperpolarize the postsynaptic cell •opening Cl− channels

48. A 24-year-old woman with marfan syndrome came to the physician 1 week after a home pregnancy test results were positive. Previous evaluations Showed mild coarctation of the thoracic aorta with mild dilation of the ascending aorta, and mild aortic regurgitation, but no significant heart failure. If her Pregnancy were to proceed, which of the following mechanisms would most likely increase the amount of aortic regurgitation in this patient?

hypervolemia

16. Shortly after a surgical procedure, a 48-year-old woman developed signs and symptoms of neuromuscular irritability, including tingling paresthesias. Gently tapping over the facial nerve in front of the ear results in reflex contraction of the facial muscles. Which of the following electrolyte abnormalities is the most likely cause of these findings?

hypocalcemia

nephrotic syndrome

increased permeability of the GBM , Generalized pitting edema , proteinuria, Hypoalbuminemia

Cell surface receptor antagonism

is not a mechanism of action of steroid hormones. Steroid hormones are hydrophobic, which means that they are able to diffuse across a cell's plasma membrane and bind to receptors once inside the cell.

3. A 35-year-old man comes to the emergency department because of a 2-hour history of moderate chest pain. He has had a 2-kg [4.4-lb] weight loss During the past 2 months. His pulse is 100/min, respirations are 25/min, and blood pressure is 135/90 mm Hg. An ECG shows no abnormalities. A barium Swallow shows a dilated esophagus with beak-like narrowing at the level of the lower esophageal sphincter [LES]. a biopsy specimen of the LES is most Likely to show which of the following?

loss of neurons in the myenteric plexus

110. A 26-year-old woman comes to the emergency department because of a 3-day history of nausea and vomiting. Her last menstrual period was 9 weeks Ago. a urine pregnancy test is positive. Ultrasonography shows an intrauterine pregnancy consistent in size with a 7-week gestation. The hormone that Was measured in this patient's urine to detect the pregnancy is also directly responsible for which of the following processes?

maintenance of the corpus luteum

11ß-hydroxylase deficiency

manifests with hypertension, hypokalemia, and virilization in females. By closely paying attention the patient's blood pressure, labs, and sexual characteristics, you can differentiate among the causes of congenital adrenal hyperplasia.

21-Hydroxylase deficiency

manifests with hypotension, hyperkalemia, and continued production of sex hormones leading to virilization in females. It the most common congenital adrenal deficiency and manifests in infancy with salt-wasting or in childhood as precocious puberty.

tonicity The solution would be isotonic

measure of the osmotic pressure gradient between two solutions? if the result is no effect?

you calculate membrane potential using the nearest equation [-61/ ion charge] log [concentration outer/ concentration inner]

membrane potentials to memorize

Exocytosis

membrane-bound secretory vesicles are carried to the cell membrane, and their contents are secreted into the extracellular environment

Hemophilia C

mild type; factor XI deficiency

Hydrophilic solutes (e.g., Na+)

must cross cell membranes through water-filled channels, or pores

anions

negative charged ions?

Hypernatremia

no change in Resting Membrane Potential and larger action membrane potential

Second-degree heart block

occurs when the action potential fails to reach the ventricles some, but not all, of the time

103. An 18-year-old woman, gravida 1 para 1, comes to the physician for a routine postpartum examination. She says that she often has milk leakage even When she is not ready to breast-feed ehr 6-week-old son. She reports that this symptom is particularly severe whenever he begins to cry. The physician Reassures her that this is an entirely normal response. This reaction is likely caused by psychogenic stimuli that promote secretion of which of the Following mediators?

oxytocin

5. A 63-year-old man comes to the physician because of a 3-month history of abdominal pain that is only partially relieved by antacids. He states that he has Also tried fasting, but it has had little to no effect on the pain. Palpation of the abdomen shows exquisite tenderness focused on the right of the midline. Laboratory studies show a fasting serum gastrin concentration of 800 pg/mL [N < 100] and no evidence of helicobacter pylori infection. Secretin infusion After the patient has fasted increases serum gastrin concentration to 1150 pg/mL. Secretion of which of the following is also most likely increased in this Patient as the result of this infusion?

pancreatic bicarbonate

Early PCT

part of the nephron that contains brush border

P50 - a standard measure of hemoglobin's affinity for oxygen and is about 25 - 26 mm Hg in normal individuals.

partial pressure of oxygen in the blood when 50% saturated

88. A 4-year-old child signs of precocious [early onset] puberty is brought to a clinic for evaluation and found to have a congenital deficiency of 21-b-Hydroxylase. Feedback inhibition of the pituitary gland is lost and excess ACTH is secreted. As a result, which of the following happens?

precursors to cortisol synthesis increase.

glucosuria In adults, at plasma glucose of ∼ 200 mg/dL, glucosuria begins (threshold). At rate of ∼ 375 mg/min, all transporters are fully saturated (Tm) Pregnancy - ↑ GFR -glucosuria

presence of glucose in the urine

collecting tubule

reabsorbs Na+ in exchange for secreting K+ and H+. Aldosterone - acts on mineralocorticoid receptor -> mRNA -> protein synthesis. •In principal cells: activates Na+/K+ pump, ↑ epithelial Na+ channel activity -> ↑ K+ secretion. •In a-intercalated cells: ↑ H+ ATPase activity -> H+ secretion ↑ HCO3−/Cl− exchanger activity. ADH - acts at V2 receptor -> insertion of aquaporin H2O channels on apical side. 3-5% Na+ reabsorbed 70% of urea is reabsorbed in presence of ADH K++ is secreted (aldosterone) or reabsorbed (low K diet) 5% Mg++ reabsorbed H2O is reabsorbed (ADH)

Early distal convoluted tubule

reabsorbs Na+, Cl−. Impermeable to H2O. Makes urine fully dilute (hypotonic). PTH - activates Ca2+/Na+ exchange -> Ca2+ reabsorption. 5-10% Na+ reabsorbed 8% Ca++ impermeable to urea

thick ascending limb

reabsorbs Na+, K+, and Cl−. Indirectly induces paracellular reabsorption of Mg2+ and Ca2+ through lumen potential generated by K+ backleak. Impermeable to H2O impermeable to urea Makes urine less concentrated as it ascends. 10-20% Na+ reabsorbed. 60% Mg++ 25% Ca++ 20% K+

Sinus bradycardia

regular rhythm, below 60 beats/minute

Loop of Henle

section of the nephron tubule that conserves water and minimizes the volume of urine

79. The ventilatory response to decreasing levels of inspired oxygen concentration for an experimental animal is shown. Which of the following labeled Figures best represents the response in this animal after removal of the carotid bodies?

straight across line Surgical removal of the carotid bodies in experimental animals and in humans results in a stable new steady state of hypoventilation. The animal then maintains a "normal" PaCO2 that is a few mmHg higher than in animals with intact peripheral chemoreceptors

Afterload

the "load" that the heart must work against •aortic pressure - hypertension •TPR •aortic stenosis

down regulation

the decrease in population of receptors on a cell surface •This is usually due to overstimulation of receptors •As a result, a greater amount of agonist will be required to have the same effect •This commonly occurs with opioids, benzodiazepines and other drugs

S > T > U Compliance (C) is the change in lung volume ( V) that occurs for a given change in the transpulmonary pressure ( P), that is, C V/ P. ( e transpulmonary pressure is the difference between the alveolar pressure and pleural pressure.) Because compliance is equal to the slope of the volume-pressure relationship, it should be clear that curve S represents the highest compliance, and that curve U represents the lowest compliance.

the diagram above shows three different compliance curves (S, T, and U) for isolated lungs subjected to various transpulmonary pressures. Which of the following best describe the relative compliances for the three curves? Select one: a. S > T < U b. S > T > U c. S < T > U d. S = T = U e. S < T < U

Driving force

the difference between the actual, measured membrane potential (Em ) and the ion's calculated equilibrium potential (EX)

Equilibrium potentia

the diffusion potential that exactly balances (opposes) the tendency for diffusion caused by a concentration difference

Systemic blood vessels the innervation and function of systemic blood vessels is influenced primarily, if not exclusively, by the sympathetic nervous system.

the function of which of the following organs or systems is dominated by the sympathetic nervous system? Select one: a. Gastrointestinal motility b. Systemic blood vessels c. Heart d. Salivary glands e. Gastrointestinal gland secretion

Pinocytosis

the invagination of the cell membrane to form a pocket, which then pinches off into the cell to form a vesicle filled with a large volume of extracellular fluid and molecules within it

preload

the load on the muscle in the relaxed state •load on ventricular muscle at the end of diastole •Left ventricular end-diastolic volume (LVEDV) •Left ventricular end-diastolic pressure (LVEDP) •↑ - Add volume , Slow heart rate, Constrict veins •↓ - Remove volume, Raise heart rate, Pool blood in veins

Resting membrane potential -70 to -80 is close to the equilibrium potentials for K+ and Cl− therefore, the permeability to these ions at rest is high

the potential difference that exists across the membrane of excitable cells such as nerve and muscle in the period between action potentials - at rest −70 to −80 mV

miniature end plate potential (MEPP)

the smallest possible change in membrane potential of the motor end plate

B A spirometer can be used to measure changes in lung volume, but cannot determine absolute volume. It consists of a drum filled with air inverted over a cham- ber of water. When the person breathes in and out, the drum moves up and down recording the changes in lung volume. e spirometer cannot be used to mea- sure residual volume (RV) because the residual volume of air in the lungs cannot be exhaled into the spirome- ter. e functional residual capacity (FRC) is the amount of air left in the lungs after a normal expiration. FRC cannot be measured using a spirometer because it contains the RV. e total lung capacity (TLC) is the total amount of air that the lungs can hold after a maximum inspiration. Because the TLC includes the RV it cannot be measured using a spirometer. TLC, FRC, and RV can be determined using the helium dilu- tion method or a body plethysmograph.

the various lung volumes and capacities include the total lung volume (TLC), vital capacity (VC), inspiratory capacity (IC), tidal volume (VT), expiratory capacity (EC), expiratory reserve volume (ERV), inspiratory reserve volume (IRV), functional residual capacity (FRC), and residual volume (RV). Which of the following lung volumes and capacities can be measured using direct spirometry without additional methods? Select one: a. A b. B c. D d. C e. E

more tension when the muscle contracts isometrically than isotonically

there is more tension when the muscle contracts ______________ than ______________

DHP receptor

voltage sensor in the t tubules, communicates to the ryanodine receptors

Third-degree (complete) heart block

when conduction of the action potential from the atria to the ventricles is completely interrupted. Under these conditions, pacemaker cells within the His-Purkinje system or the ventricular muscle cause the ventricles to beat at a low rate (idioventricular rhythm) independently of the atria there is no electrical communication between the atria and ventricles. The p-waves and QRS complexes on the electrocardiogram have no relationship to each other. Clinical symptoms are syncope, dizziness, and hypotension. Acute heart failure can result. A pacemaker must be urgently placed.

Digitalis/ glycosides

•Inhibit the Na/K ATPase causing an increase in cytosolic Na+ •Elevated Na+ will exchange with calcium via the Na/Ca antiporter •Elevated calcium levels will increase myosin-actin crossbridge formation and inotropy will increase •The greater the cytosolic calcium in skeletal muscle, the greater the force generated because of recruitment of more Myosin-Actin crossbridges •This may also lead to tetany

Torsades de pointes

• Polymorphic ventricular tachycardia •shifting sinusoidal waveforms

right sided heart failure

•"cor pulmonale" •Inability to pump blood to the pulmonary circulation -> ↑ RV pressure -> ↑ RA pressure -> ↑ systemic venous pressure (↑ jugular venous pressure) -> ↑ Pc -> lower extremity edema, liver congestion Hepatomegaly (nutmeg liver), Jugular venous distention, Peripheral edema•"cor pulmonale" •Inability to pump blood to the pulmonary circulation -> ↑ RV pressure -> ↑ RA pressure -> ↑ systemic venous pressure (↑ jugular venous pressure) -> ↑ Pc -> lower extremity edema, liver congestion Hepatomegaly (nutmeg liver), Jugular venous distention, Peripheral edema

•> 5.0 mEq/L = hyperkalemia •< 3.5 mEq/L = hypokalemia

•> 5.0 mEq/L = ____________ •< 3.5 mEq/L = ____________

Wolff-Parkinson-White syndrome

•Abnormal fast accessory conduction pathway from atria to ventricle •shortened PR interval

Hypokalaemia

•Flattened T wave •Large U wave

aortic regurgitation

•Increased ventricular diastolic volume •Murmur: early diastolic; decrescendo, begins at S2. •chamber enlargement, hypertrophy, systolic dysfunction •Decreased aortic diastolic pressure •↑ SV, ↑ EDV, ↑ ESV

Mitral stenosis

•Left atrial pressure increases •associated with rheumatic fever •Increased pulmonary venous, capillary (edema, dyspnea), pulmonary arterial pressures •Murmur: diastolic; opening snap after S2, followed by a low-frequency decrescendo murmur (diastolic rumble) •↓ EDV, ↓ ESV , ↓ SV

Hypertension

•Primary •Na+ intake •NSAIDs •Renal artery stenosis •Coarctation of the Aorta •in Pregnancy

Autoregulation

•The maintenance of a constant blood flow to an organ in the face of changing arterial pressure

Myogenic autoregulation

↑ arterial pressure -> stretch of the afferent arteriole -> reflex contraction of smooth muscle in the blood vessel walls -> afferent arteriole constricts with high pressure -> resistance to blood flow

Tubuloglomerular feedback

↑ arterial pressure -> ↑ RBF, ↑ GFR -> ↑ delivery of solute and water to the distal tubule -> ↑ NaCl is delivered by primary urine to the macula densa (a part of the juxtaglomerular apparatus) -> adenosine release in the macula densa -> local constriction of afferent arterioles -> ↓ RBF and GFR back to normal