Exam 3 QA
In the partially labeled Wigger's diagram shown above, the ejection fraction is closest to: A. 0.6 B. 50 C. 2.6 D. 120
A
The figure below shows how pressure inside the left ventricle and the volume of the ventricle co-vary during a cardiac cycle. The different letters mark different events in the cardiac cycle: end of systolic contraction, opening of the atrioventricular valve etc. Which way round the loop does the cycle go? A, Counter-clockwise (in order A to B to C to D to E to F) B. clockwise (in order A to F to E to D to C to B to A)
A
A The snorkel increases the anatomic dead space. Therefore, a smaller fraction of the inspired air makes it to the respiratory zone, where it is available for gas exchange.
A member of the UK swim team decides to use a snorkel to improve her competition time. After a few laps around the pool, she feels more "winded" than normal. Why do you think this happens? A. The snorkel increased the anatomic dead space. B. The snorkel decreased airway resistance. C. The snorkel decreased ventilation/perfusion. D. The snorkel increased the physiologic dead space
The large bolus of potassium chloride increased the extracellular potassium concentration. This reduced the concentration gradient governing the net movement of potassium ions out of cardiac cells. The cells depolarized (membrane potential became more positive) and the cells could not propagate repeated action potentials.
A patient died after they were accidentally injected with a large bolus of potassium chloride. What killed them?
Oxygen moves from one compartment to another by diffusion only. If we consider that room air has a Po2 ~ 160 mmHg, it is not possible for arterial Po2 to be greater than this number. In consequence, something is wrong with the measurement.
A patient shows up at the clinic with some mild respiratory discomfort. He is in an exam room, breathing room air. You take a sample of venous blood; it has a Po2 of 60 mmHg. Then, the attending physician asks you to measure arterial blood gases. The result comes back from the lab, showing arterial Po2 at 200 mmHg. You look at the number and then you say "the blood gas machine is broken". How do you know that?
B
A woman has a diastolic blood pressure of 90 mm Hg. Her mean arterial blood pressure is 100 mm Hg. Her systolic blood pressure is about A. 93 mm Hg B. 120 mm Hg C. 110 mm Hg D. 80 mm Hg
D
Aortic compliance A. increases the mean arterial pressure required to maintain a given cardiac output. B. decreases mean arterial pressure and cardiac output. C. increases mean arterial pressure and cardiac output. D. reduces the mean arterial pressure required to maintain a given cardiac output
An asthma attack reflects an acute increase in airway resistance, mostly due by intense bronchoconstriction (contraction of the smooth muscle of the small airways), plus obstruction by increased mucus secretion.
Asthma is basically an inflammatory disease. Explain why it is difficult to breathe during an asthma attack.
Which shows ventricular myocyte and which shows SA nodal cell?
A. ventricular myocyte B. SA nodal cell
A
AIDS (acquired immune deficiency syndrome) results mainly from the loss of helper T cells as a consequence of HIV infection. With that in mind, what immune mechanisms would you expect to be most affected? A. Antibody production B. Phagocytosis by macrophages C. Recognition of PAMPs (pathogen-associated molecular patterns) D. Alternative complement pathway
Helper T cells are needed for the activation of B and cytotoxic T cells. If the helper T cells are eliminated, then both humoral and cellular immunity are impaired. Therefore, AIDS patients are very susceptible to opportunistic infections and cancer.
Acquired immunodeficiency syndrome (AIDS) is a viral infection that results in the loss of helper T cells. What would you expect to be the consequences on humoral and cellular immunity?
A
Active hyperemia A. increases the blood supply to tissues that are using a lot of oxygen. B. is an example of extrinsic regulation. C. is most prevalent in the lymphatic system. D. decreases the blood supply to tissues that are using too much oxygen.
C
Blood clots are composed primarily of A. thrombin B. collagen C. fibrin D. fibrinogen
In the Wigger's diagram above, the minimum value of trace Y represents A. cardiac output. B. end-diastolic volume. C. diastolic pressure. D. systolic pressure.
C
In the partially labeled Wigger's diagram shown above, trace X could be A. aortic pressure. B. atrio-ventricular flow. C. aortic blood flow. D. atrial pressure.
C
The figure below shows how pressure inside the left ventricle and the volume of the ventricle co-vary during a cardiac cycle. The different letters mark different events in the cardiac cycle: end of systolic contraction, opening of the atrioventricular valve etc. Stroke volume could be represented by A. the horizontal distance between A and B B. the vertical distance between C and D C. the horizontal distance between A and C D. the vertical distance between A and F
C
a) Phagocytes cannot produce superoxide anions, hydrogen peroxide, and hydroxyl radicals. b) Bacteria cannot be digested and destroyed. c) Patients with this disease have more infections, and of greater severity.
Chronic granulomatous disease is a rare disorder in which phagocytes lack the enzymes needed to produce the reactive oxygen compounds that breakdown bacteria. What would be 3 consequences of this disease?
The negative intrapleural pressure keeps the lungs "attached" to the chest wall. At the end of expiration, the chest wall tends to recoil outwards, while the lungs tend to collapse. Since these structures are pulling in the opposite direction, the pressure in the virtual space between them (intrapleural space) is negative.
Explain why intrapleural pressure is negative at the end of a quiet breath (expiration).
B
F-type sodium channels are unusual because they A. are activated by the ligand fibrinogen. B. open when the cell is hyperpolarized. C. allow the passage of Ca2+ ions. D. are not voltage-gated.
C
Hematocrit is the percentage of blood that is A. plasma B. leukocytes C. red blood cells D. buffy coat
B
Hemoglobin will bind all of the following, EXCEPT A. hydrogen ions B. sodium hydroxide C. carbon monoxide D. carbon dioxide E. oxygen
E
In a patient with anemia (decreased hematocrit, low number of red blood cells), one would expect a decrease in the: A. arterial % saturation of the Hb-O2 curve B. arterial Pco2 C. arterial PO2 D. all answers are correct E. arterial O2 content
C
In contrast to other lymphoid cells, natural killer cells mediate non-specific responses, except in the case of: A. activation of the alternative complement pathway. B. opsonization of viral proteins. C. cytotoxicity triggered by antibodies. D. formation of the membrane attack complex.
D
If blood is flowing though a vessel with a diameter of 1 mm and the vessel dilates to a diameter of 2 mm, the rate of flow will A. decrease 4 times. B. decrease 16 times. C. increase 4 times. D. increase 16 times.
C
If the arteriole supplying a capillary network constricted, the rate at which fluid moved from the interstitial fluid to the plasma near the venous end of the capillary would A. increase because of decreased capillary osmotic pressure. B. decrease because of decreased capillary osmotic pressure. C. increase because of decreased capillary blood pressure. D. decrease because of decreased capillary blood pressure.
C
If the expiratory muscles were weakened you would expect the biggest increase in the volume of the a. functional residual capacity b. total lung capacity c. residual volume d. tidal volume e. expiratory reserve volume
B
In the vascular system, nitric oxide A. activates PKA. B. is released by endothelial cells. C. can only cross the capillary wall via bulk flow. D. stimulates beta-adrenergic receptors and initiates contraction.
How does this branching protect the airways?
It is difficult to block all the airways, unless it is a large object caught in one of the large airways (trachea, main bronchi). The anatomical arrangement makes it possible to create a large pressure below the obstruction, and then the object can be dislodged by coughing or sneezing.
The membrane attack complex (MAC) is a multiunit structure that forms "pores" or "channels" in microbial membranes; it results from the activation of the classic complement pathway. Perforin is a protein similar to MAC, and it forms pores in cellular membranes as well. However, it is contained in intracellular vesicles that are released after cytotoxic T cell activation.
What is the difference between the membrane attack complex and perforin?
A
What is the single most important difference between ventricular function in the right and left ventricles? A. Pressure B. Ejection volume C. Heart rate D. Excitation-contraction coupling mechanism
B Since the diaphragm is an inspiratory muscle, inspiratory volumes and capacities will decrease.
John Doe underwent emergency neck surgery last week after a bad car accident. During the operation, the surgeons found that both phrenic nerves were cut and the diaphragm was completely paralyzed. What lung volumes and capacities will be affected the MOST? A. Expiratory reserve volume B. Inspiratory reserve volume C. Functional residual capacity D. Residual volume
Pressure in the chest, pain or discomfort in arms, neck or jaw, unexplained shortness of breath, nausea, lightheadedness, breaking out in a cold sweat. A coronary artery becomes blocked, often by a clot, stopping blood flow to part of the heart. The heart muscle that no longer gets supplied with blood becomes ischemic and dies. Heart muscle barely regenerates so the muscle that dies is not replaced. The damage becomes permanent.
List 4 symptoms of a heart attack, describe what happens, and explain why t is bad
A
Normally, inflammation is a response that localizes to the site of injury. Which of the following is not characteristic of inflammation? A. It is only seen in innate immune responses. B. There are local changes in vascular permeability. C. It is induced by released chemical mediators. D. Macrophages migrate into the site of injury.
what does the figure show? Why can we say that the peripheral chemoreceptors are relatively insensitive to Po2?
The figure below shows the ventilator response to changes in Po2. From it, we can infer that the firing rate of peripheral chemoreceptors does not change significantly until arterial Po2 drops by ~20%. Remember that the hemoglobin saturation curve is flat at 100% at a Po2 between 80-100+ mmHg. Therefore, oxygen content does not change significantly if Po2 drops from ~100 to ~80 mmHg. In other words, the peripheral chemoreceptors are calibrated to account for the effect of hemoglobin on oxygen content.
B If the alveoli are filled with fluid (saline, surfactant, even water), then there is no surface tension. Under that condition, lung compliance would increase even more, but there would be less gas exchange.
Surfactant forms a thin layer inside the alveoli and increases lung compliance. What would happen if alveoli were completely full of surfactant? A. Lung compliance would not change. B. There would be no gas exchange. C. Ventilation/perfusion would increase. D. Lung compliance would decrease.
B
The development of self-tolerance depends on which of the following mechanisms? A. Deletion of lymphoid clones specific to microbial antigens. B. Deletion of T cell clones specific to self antigens. C. Preemptive inactivation of all lymphoid clones. D. Continuous expansion of all lymphoid clones.
C
The distance between alveoli and their capillaries is very short (1 µm or less). Why is this important? A. The shorter the distance, the lower the amount of ATP needed to pump O2 into the blood. B. The short distance slows down blood flow and allows for equilibration with alveolar gas. C. The shorter the distance, the faster the diffusion of gas across the tissue barrier.You Answered D. The shorter the distance, the greater the area available for gas diffusion.
A
The innate immune responses induced by Toll-like receptors depend on: A. The recognition of pathogen-associated molecular patterns. B. Specific Fc-receptors on the surface of B lymphocytes. C. Binding pathogen-pattern recognition receptors. D. Blocking the release of viral particles from infected cells.
A
Which of the following are characteristics of the adaptive immune system? A. Its response can be specific to the antigen. B. The timing and intensity of the response is constant. C. It relies only on lymphoid cells. D. Its final stage is tissue repair.
D
Which of the following comparisons is correct at the end of expiration when there is no airflow?(Patm = atmospheric pressure, Ppl = intrapleural pressure, PA = alveolar pressure and Pm = mouth pressure, same as atmospheric pressure). Be sure all indicated relationships (>, <, =) are correct. a. Patm = Ppl < PA < Pm b. Patm > Ppl = PA < Pm c. Patm > Ppl > PA > Pm d. Patm > Ppl < PA = Pm e. Patm < Ppl > PA < Pm
C
Which of the following is a characteristic of the adaptive immune system? a) It includes inflammation. b) It includes defenses on the body surfaces. c) It is a specific response against microbial antigens. d) It activates the alternative complement pathway
They are hypertensive (systolic is more than 140 mm Hg) and their heart rate is a little high. Resting heart rate is typically in the 60 to 100 beats per minute range but it depends on the person.
our significant other has a blood pressure of 150 / 90 mm Hg and a heart rate of 105 beats per minute at rest. Do they have hypertension? Is their heart rate normal ?
C
Which of the following statements is TRUE? A. Increased hemoglobin concentration increases the % Hb saturation. B. About 5% of the O2 is transported dissolved in plasma. C. Venous blood is usually 75% saturated with oxygen. D. The arterial PO2 is usually greater than the alveolar PO2. E. The arterial PO2 is usually around 40 mm Hg.
Because CO2 is hydrated to carbonic acid when dissolved in plasma (or water) in a reaction catalyzed by carbonic anhydrase.
Why do we say CO2 is an "acid"?
When we hyperventilate, we exhale CO2 at a rate faster than its production, which is equivalent to eliminating acid from the plasma (see 5.). Pco2 decreases and pH goes up (alkalosis).
Why does CO2 content and blood pH change when you hyperventilate?
C Because more oxygen flows into the alveoli than can be taken up by the blood (since less is consumed by the tissues). Therefore, alveolar Po2 increases.
Why does increased alveolar ventilation with no change in metabolism increase alveolar PO2? A. Breathing slows down. B. Oxygen diffusion is improved. C. Less O2 is taken up by the blood. D. Too much perfusion, not enough ventilation.
B Air flow is zero in both because the alveolar pressure is the same as atmospheric pressure. Therefore, there is no pressure gradient for air flow.
Why is air flow the same at the end of inspiration and at the end of expiration? A. Because intrapleural pressure is the same in both. B. Because alveolar and atmospheric pressures are the same. C. Because the recoil of the chest wall is the same in both. D. Because it is the same tidal volume in different directions.
D
With a tidal volume of 600 mL, a dead space of 200 mL and a respiratory frequency of 20, the alveolar minute ventilation would be A. 12 L B. 4 L C. 6 L D. 8 L E. 16 L
During rapid filling, the stiff heart muscle would require a greater change in pressure to stretch it. It would be likely that the filling would be delayed in this state. Atrial contraction might become more important in establishing the EDV. The rapid ejection phase is due to muscle contraction and the stiffness probably doesn't affect the contraction much - it could actually help to empty the ventricle faster!
With age, the ventricles of the heart become stiffer and difficult to stretch. Would this change be more likely to affect the rapid filling phase or the rapid ejection phase? Explain your answers.
A
A blood sample taken from a patient has an arterial Po2 of 50 mm Hg and an arterial Pco2 of 37 mm Hg. Any reflex changes in ventilation in this patient are due primarily to the A. peripheral chemoreceptors B. irritant receptors C. central chemoreceptors D. pulmonary C fibers E. pulmonary stretch receptors
B
Baroreceptors are important for A. intrinsic control of arteriolar diameter. B. short-term regulation of arterial blood pressure. C. maintaining the Frank-Starling relationship. D. long-term regulation of arterial blood pressure.
D
C-reactive protein is an opsonin because it: a) creates channels in bacterial membranes. b) increases C3b binding to a microbe. c) forms the pathogen-associated molecular patterns. d) enhances phagocytosis.
B
Calcium-induced calcium release describes a situation in which A. troponin releases Ca++ to initiate muscle contraction. B. Ca++ enters the cell and causes further Ca++ to be released through ryanodine receptors. C. Ca++ enters through ryanodine receptors and causes further Ca++ to be released. D. Ca++ released at the motor endplate enters the cell and initiates contraction.
C
Clonal activation is important for the ________________ immune system, and it involves the proliferation of _____________ A. innate, T cells B. innate, natural killer cells C. adaptive, B cells D. adaptive, tissue macrophages
C The bear hug would compress the ribs, decreasing thoracic volume even more. Therefore intrapleural pressure would become less negative.
Consider the direction of the lung and chest wall elastic recoils in a person at the end of expiration. What would happen if someone gives that person a strong bear hug at that exact moment? A. Alveolar pressure would become negative. B. There would be a sudden influx of air into the lungs. C. Intrapleural pressure would become less negative. D. Intrapleural pressure would become more negative.
The figure below shows how pressure inside the left ventricle and the volume of the ventricle co-vary during a cardiac cycle. The different letters mark different events in the cardiac cycle: end of systolic contraction, opening of the atrioventricular valve etc. Which point marks the end of the diastolic phase of the cardiac cycle? A. F on the diagram B. D on the diagram C. A on the diagram D. C on the diagram
D
The figure below shows how pressure inside the left ventricle and the volume of the ventricle co-vary during a cardiac cycle. The different letters mark different events in the cardiac cycle: end of systolic contraction, opening of the atrioventricular valve etc. At which point does the aortic valve open? A. A B. C C. F D. D
D
B
Cytotoxic T cells are the only lymphoid cells that interact with class I MHC antigens. This makes them important for: A. activation of B cell clones. B. identification of virus-infected cells. C. destruction of extracellular parasites. D. immune memory.
a) Opsonization b) Activation of classic complement pathway: Production of C3b (oposonization) Production of the membrane attack complex c) Antibody-dependent cellular cytotoxicity after binding to natural killer cells d) Direct neutralization of toxins and viruses
Describe 4 ways antibodies lead to the inactivation or destruction of bacteria and viruses.
- The electrical activity of the heart usually begins in the cells of the SA node which are located in an area of the right atrium where the specialized myocytes depolarize most rapidly. - From there the action potential is conducted through the atrial muscle and intermodal pathways to the AV node where the transmission of the electrical signal is delayed. - The electrical signal leaves the AV node through the Bundle of His which divides into 2 bundles before synapsing with the Purkinje fibers. These specialized muscle cells distribute the cardiac action potential rapidly throughout the ventricular muscle, exciting the ventricular myocytes. -The action potentials of these cell types all show a delayed repolarization compared to neuronal cells.
Describe the normal pathway for electrical activity through the heart. What cell types are involved and what do the individual action potentials look like for each cell type?
The horizontal position in swimming increases the venous return from the lower extremities. In addition, the weight/force of the water tends to "squeeze" some blood out of the exterior veins. Since swimming uses most of the musculature throughout the body, the muscle pumps also increase the movement of blood back to the heart. All three of these actions increase venous return. The increased venous return (VR) leads to an increased EDV which, through the Frank- Starling relationship, increases the SV. In jogging, some blood pools in the lower extremities because of the force of gravity. The muscle pumps do help limit this pooling.
During swimming there is a large increase in end diastolic volume (EDV) of the heart. This leads to an increase in stroke volume. Explain how the increased EDV leads to an increase in stroke volume. Why would EDV be markedly increased in swimming but not in jogging?
The small airways are linked by connective tissue to the alveoli. When the alveoli expand during inspiration, they pull on the airways and distend them, decreasing resistance.
Explain how "lateral traction" helps to keep airways open.
Surfactant is a surface-active (soap-like) mixture of phospholipids and proteins that decreases surface tension in the alveoli, increasing compliance.
How does surfactant influence lung compliance?
A. Ca channel blockers can be used - these can work by relaxing smooth muscle to decrease peripheral resistance and/or by decreasing the Ca influx into ventricular myocytes thereby decreasing cardiac contraction and stroke volume. B. Beta-adrenergic receptor blockers would decrease heart rate by acting on the SA nodal cells to block sympathetic input and also on ventricular myocytes to decrease their force of contraction. C. Alpha-adrenergic receptor blockers would decrease the contraction of vascular smooth muscle leading to a decrease in venous return (veins) and peripheral resistance (arterioles). D. ACE inhibitors - these block the action of angiotensin converting enzyme thereby decreasing the amount of angiotensin II available. AII normally reduces the uptake of Norepinephrine - therefore more NE exists in the synapse. This increased NE leads to increased heart rate and blood pressure. So, blocking the action of ACE leads to decreased AII, which in turn leads to increased NE uptake and reduced NE in the synapse - hence a reduction in SNS activity. E. Diuretics - these work on various parts of the kidney to increase salt and water excretion leading to a lower blood volume - and a lower cardiac output and blood pressure. F. there are other possibilities - decrease aldosterone secretion; decrease cortisol which has a permissive action on sympathetic neurotransmission.
Hypertension is a serious risk factor for several different diseases. List the types of drugs that might be used to lower the resting blood pressure - describe the mechanisms that would be affected with each of these drugs and the potential negative side-effects that might occur.
Mild hypertension can often be treated by lifestyle changes (e.g. getting more activity, reducing salt intake, managing stress). If that doesn't work, speak to your health‐ care provider who will probably prescribe medications including diuretics, calcium channel blockers and/or ACE inhibitors.
If you had mild hypertension, how would you treat it?
D Oxygen content decreases (no red blood cells = no hemoglobin), but Po2 remains normal (dissolved oxygen). A likely response is a compensatory increase in cardiac output, trying to deliver the amount of oxygen needed by the tissues. The ventilatory drive provided by the peripheral chemoreceptors may not change since these receptors are sensitive to changes in Po2 (which is set by the dissolved O2).
Imagine that 80% of the blood in a subject is replaced with pure plasma (no red blood cells). What do you think would be a likely compensatory response? A. All answers are correct. B. Ventilation will increase. C. Arterial PO2 will increase. D. Cardiac output will increase.
B Lung compliance would decrease -- it would be more difficult to inflate the lungs. Gas exchange would be compromised due to the decrease in the surface area available for diffusion and the increase distance between alveoli and capillaries.
In lung fibrosis, the normal lung parenchyma is replaced by fibrotic scar tissue. What do you think would happen to lung compliance and gas exchange? A. No change in lung compliance, gas exchange decreases B. Lung compliance and gas exchange decrease C. Lung compliance increases, gas exchange decreases D. Lung compliance increases, gas exchange is not affected.
D
In patients with respiratory acidosis, you would expect: A. them to have more carbonic anhydrase. B. them to be hyperventilating. C. a decreased anatomic dead space. D. their hemoglobin-O2 saturation curve to be shifted to the right. E. their arterial Pco2 to be lower than normal.
A
In the apex (top) of the lung during quiet breathing, one would expect the ____________ to be proportionally greater than the _____________ leading to a ____________ V/Q ratio. A. ventilation, perfusion, high B perfusion, ventilation, low C. perfusion, ventilation, ideal D. perfusion, ventilation, high E. ventilation, perfusion, low
B
James Black, the inventor of beta-blockers, was like Lister (the first doctor to use antiseptics) and Fleming (the person who discovered antibiotics), from A. England B. Scotland C. Wisconsin D. Kentucky
E
Most of the CO2 produced by cells is transported in the blood as A. carbaminohemoglobin B. dissolved CO2 C. carboxyhemoglobin D. carbonic anhydrase E. HCO3
Blood cells can go to one organ or the other, but they don't go through one organ and on to the next. This is useful because it means that every organ gets supplied with fresh blood. The body can also divert blood to different organs on demand.
Most of your organs are supplied with blood "in parallel". What does this mean and why is it useful
At least three reasons: a) To facilitate the diffusion of cytokines, chemokines, and other inflammatory mediators to the affected area. b) To facilitate the movement of inflammatory cells to the affected area. c) The fluid (including antigens and inflammatory cells - macrophages and lymphocytes most importantly) is removed from the interstitial space via lymph and the lymphatic system. Lymph flows through the lymph nodes, where lymphocytes are exposed to the invading antigens, triggering the adaptive immune response.
One of the consequences of inflammation is localized vascular permeability in the area of damage. Why do you think this is a part of the inflammatory process?
D Increase alveolar Po2, decrease alveolar Pco2, decrease arterial Pco2 resulting in respiratory alkalosis
One of your classmates hyperventilates uncontrollably after getting an "A" in the PGY 412G exam. He will: A. develop respiratory alkalosis B. decrease alveolar PCO2 C. increase alveolar PO2 D. all answers are correct
A
Poiseuille's law implies that flow through a pipe increases when A. the internal radius doubles but the length of the pipe halves. B. the viscosity of the fluid doubles. C. the length of the pipe doubles but the internal radius halves. D. fluid viscosity halves but the length of the pipe doubles.
If the heart develops less force, it takes longer to generate pressures great enough to open the semilunar valves, therefore the isovolumic period increases. With hypertension and high pressure in the aorta, the heart has to generate a greater pressure before the valve opens, therefore the isovolumetric phase would be increased (what would happen if there was a positive inotropic effect?)
Predict the effects of a reduced rate of cardiac muscle contraction on the duration of the isovolumetric contraction phase of the cardiac cycle What would be the likely effects of hypertension on the duration of the isovolumetric phase?
Standing, Running, Swimming Exercise increases cardiac output, activity increases muscle pump, pushing blood back towards the right heart. The horizontal posture in swimming and the additional pressure from the surrounding water pushes more blood from the legs to the heart.
Put the following activities in order based on the volume of your right ventricle (smallest volume first) while you are doing them: Standing, Swimming, Running. Why?
A
Red blood cells move at the slowest velocity in A. capillaries B. aorta C. vena cava D. arterioles
B
The T wave in an ECG trace occurs closest in time to A. the atrial kick. B. closing of the aortic valve. C. isovolumic ventricular contraction. D. closing of the atrioventricular valve.
C As the airways get obstructed with the thick mucus, resistance to airflow increases. In addition, the thick mucus is difficult to move, so microorganisms are not cleared and are more likely to cause infections.
The airways of patients with cystic fibrosis produce very thick mucus that is difficult to clear. What are likely consequences of this effect? A. Their gas exchange is accelerated. B. Their airway resistance will decrease. C. The patients will have more lung infections. D. All answers are correct
B
The basic respiratory rhythm is generated in the A. spinal cord B. medulla C. cortex D. pons E. cerebellum
Explain how the branching of the airways influences gas exchange.
The branching of the airways decreases resistance to air flow, slows down air (more time to warm and moisten the air, and more time for gas exchange), and increases the surface area available for diffusion (300 million alveoli = 200 m2 area)
A
The conducting airways a. have a volume equal to the anatomic dead space. b. help to sense the atmospheric O2 concentration. c. contain alveoli. d. include the respiratory bronchioles. e. are lined with type I cells that secrete surfactant.
C
The correct sequence of events in cardiac excitation is A. sinoatrial node, bundle branch, atria, atrioventricular node, ventricle B. atrioventricular node, atria, sinoatrial node, bundle branch, ventricle C. sinoatrial node, atria, atrioventricular node, bundle branch, ventricle D. atria, sinoatrial node, bundle branch, atrioventricular node, ventricle
The attached traces represent EKGs from 3 different people. Identify the P wave, QRS and T waves for each of them. What is the heart rate for each of them? Which trace is abnormal and what is the likely problem for this individual?
The heart rate for trace 1 is 75-80 bpm depending on which R-R interval you look at. There is .75-.8 sec between beats. For trace 2, heart rate is 60 sec/.8 sec = 75 bpm; for trace 3 heart rate is 60 sec/ .75 sec = 80 bpm. Trace 3 is abnormal in that the QRS is much longer than normal. This is indicative of poor conduction through the Purkinje system so that the ventricular myocytes are not recruited almost synchronously as one would normally expect.
C
The most important cells for hemostasis (the prevention of blood loss) are A. thromboxin B. erythrocytes C. platelets D. neutrophils
D
The presence of surfactant a. depends on secretion by the type I alveolar cells. b. encourages the collapse of small alveoli into larger ones. c. increases the surface tension of the lungs. d. increases the lung compliance. e. occurs in the intrapleural space
C
The rapid increase in antibody production after repeated exposures to the same antigen is due to: a) higher levels of IgE. b) clonal proliferation of NK cells. c) the presence of memory cells. d) antibody-dependent cellular cytotoxicity.
D
The trigger calcium that initiates calcium-induced calcium release in ventricular myocytes A. enters the cell through T-type Ca2+ channels. B. is released from troponin C. C. enters the cell through ryanodine receptors. D. passes through L-type Ca2+ channels
B
Two substances that are important for localizing hemostatic action to damaged tissue are A. erythropoietin and basophils B. nitric oxide and prostacyclin C. thromboxane and fibrinogen E. erythropoietin and nitric oxide
A
Type 1 interferons are important for the innate immune system because they: A. inhibit viral replication. B. activate the complement pathway. C. trigger the release of histamine. D. serve as opsonins.
Oxygen diffuses from capillaries to the interstitium and is flow‐limited. This means that more oxygen will be delivered to muscle cells if blood is pumped through capillaries at a faster rate. Increasing heart rate, increases cardiac output.
Using your knowledge of oxygen diffusion, explain why it is useful to increase heart rate when you exercise
-- The lung tissue itself: the alveoli behave as ballons; the alveolar walls have elasticity and oppose inflation and recoil to a smaller size when air flows out. -- Surface tension: this is the cohesive force of the surface molecules in the thin layer of fluid coating the inside of alveoli.
What are the determinants of lung compliance?
Going from the alveoli to the capillaries: the alveolar wall (mainly type I alveolar cells), the interstitial space, capillary wall (the endothelial cell), the plasma, red blood cell membrane.
What are the structural barriers to gas exchange in the lungs, from alveoli to hemoglobin?
Left atrial pressure goes up in both cases. If the valve is insufficient, blood gets pushed back in to the atrium during systole. If the valve is stenotic, it doesn't open properly and less blood gets into the ventricle. The left atrial blood volume increases in both cases so pressure goes up.
What happens to left atrial pressure if a patient has mitral valve insufficiency? What if the patient has mitral valve stenosis?
B
When phagocytes cannot produce the reactive oxygen species needed to kill and break down microbes, severe chronic infections occur. Based on what you know about the innate and adaptive immune systems, what other processes would you predict to be affected in these patients? A. Activation of the alternative complement system. B. Antigen presentation to lymphocytes. C. Binding of microbial opsonins. D. Antibody production by T lymphocytes.
D
When your ventricles contract one might expect that your A. left ventricular volume increases from 65 ml to 135 ml. B. left ventricular volume increases from 5 mm Hg to 135 mm Hg. C. left ventricular volume decreases from 135 mm Hg to 5 mm Hg. D. left ventricular volume decreases from 135 ml to 65 ml.
A
Your cardiologist notices that you have a long QT interval. This could be caused by A. more Pca (calcium current) in your ventricular cells. B. more Pf (funny current) in your nodal cells. C. slow conduction in the atrioventricular node. D. more Pk (potassium current) in your ventricular cells
Assuming the garden hose is wide enough to have negligible effects on resistance, it behaves as a dead space, meaning the cousin is breathing into the same volume. In other words, he will not get fresh air from the environment.
Your cousin is too cheap to buy a regular snorkel. He tells you he plans to use a 12-ft long garden hose instead: he is sure he can use it to breathe while swimming along the bottom of the pool. Explain why he is wrong.
Her ejection fraction could be low (20 to 45%) if she has Heart Failure with Reduced Ejection Fraction, or normal (45% to 60%) if she has Heart Failure with Preserved Ejection Fraction. The latter is more common in old women. In the first case, the heart doesn't squeeze properly. In the second case, the heart doesn't fill properly. Cardiac output is reduced in both cases. She's breathless because blood is backing up in the left atrium (because it's not being pumped on). This increases pressure in the pulmonary veins and thus the pulmonary capillaries. Water is forced into the lungs by Starling forces and the lymphatic system is overwhelmed. Your grandmother is drowning.
Your grandmother has heart failure. What is her ejection fraction and justify your answer? Why is she breathless?
