BIOS 3455 Final Exam

What are stimulators of glucagon?

Amino acids CCK, gastrin Cortisol Exercise Infections Other stresses Beta-adrenergic stimulators Theophylline Acetylcholine Hypoglycemia

What is hemoglobin A1C?

Amount of glycosylated hemoglobin (Hb with glucose bound) Tells picture of last 3-4 months

What are the digestive enzymes and their optimal pH values?

Amylase: Salivary glands and pancreas (6.8-7.0) Pepsin: Gastric glands (1.5-2.5) Trypsin: Pancreas (7.8) Chymotrypsin: Pancreas (7.8) Peptidases: Pancreas (7.8-8.0) Lipase: Pancreas (7.0-9.0)

What is hyperpnea?

An abnormal increase in depth and rate of respiration.

What is dyspnea?

"Air hunger," shortness of breath, a subjective difficult or distress in breathing, usually associated with serious disease of the heart or lungs, and occurring in healthy individuals during intense physical exertion or at high altitude.

Under what conditions are bilirubin and urobilinogen observed in urine?

*Bilirubin* is formed by the breakdown of hemoglobin as an end product of heme metabolism, bilirubin is mostly bound to albumin in the blood. Free bilirubin enters the liver where it is bound to cytoplasmic proteins. It is next conjugated to glucuronic acid in a reaction catalyzed by glucuronyl transferase. The hepatic cells then excrete it into the bile as bilirubin glucuronide. In the large intestine, the bilirubin glucuronide is converted to stercobilinogen and *urobilinogen* by bacteria. Small amounts of urobilinogens enter the general circulation and are excreted in the urine. Bilirubin may be found in the urine under the following conditions: *cirrhosis, hepatitis, other liver diseases*, or when a person has *obstructed bile ducts*.

What are Boyle's and Charles' laws?

*Boyle's law* states that under constant temperature conditions, the volume of a gas in a confined space is inversely proportional to the pressure exerted by the gas. *Charles' law* states that the volume of a gas under constant pressure is directly proportional to the absolute temperature.

What is CCK?

*Cholecystokinin* (CCK) causes contraction of the gall bladder and also increases the secretion of pancreatic juice rich in enzymes. The secretion of CCK is increased by contact of the intestinal mucosa with the products of digestion, particularly peptides and amino acids, and also by the presence in the duodenum of fatty acids containing more than 10 carbon atoms. The secretion is terminated when the products of digestion move onto the lower portions of the GI tract.

How does exercise influence glucose uptake?

*Exercise* causes an increase in glucose transport into the muscle cell also, but does not require insulin to do so. Both insulin and exercise cause an increase in the number of *GLUT4* glucose transporters in the muscle cell membrane, thus increasing the permeability of the membrane to glucose.

What is GIP?

*GIP* used to be called *gastric inhibitory peptide* because it had a mild inhibitory effect on gastric motility and secretion. GIP is now referred to as *glucose-dependent insuinotropic peptide*. Once a meal has made its way to the intestines, the nutrients (especially glucose) promote GIP secretion from the intestines. GIP, in turn, promotes insulin secretion. In this way some insulin is secreted even before blood glucose increases, so that as soon as glucose is absorbed from the intestines into the circulation, the cells of the body (under the influence of insulin) are ready to take up glucose.

What is glucagon?

*Glucagon* is a polypeptide hormone composed of a chain of 29 amino acids. It mobilizes glucose, fatty acids, and amino acids from body stores into the bloodstream. Its actions are therefore reciprocal to the actions of insulin, and it is reciprocally secreted in most circumstances. Therefore, the major stimulus for its secretion is hypoglycemia. The two major effects of glucagon on metabolism are 1) the breakdown of liver glycogen (*glycogenolysis*) and 2) increased *gluconeogenesis* (the formation of glucose from non-carbohydrates, such as amino acids or glycerol). Liver glycogenolysis and gluconeogenesis will both result in an increase in blood glucose and thus increase the availability of glucose to the other organs of the body. A decrease in plasma concentration of glucose stimulates the alpha cells of the islets to secrete glucagon which in turn elevates the blood glucose by the methods noted above.

What is hypoventilation?

*Hypoventilation* (lower than normal ventilation) of the lungs results in a net gain of carbon dioxide in the body fluids because the carbon dioxide isn't being removed as fast as it is being formed. This results in a net gain of hydrogen ions due to the formation of carbonic acid. Respiration is stimulated by this increase in H+ ions. Elevation of respiratory rate and depth occurs until carbon dioxide and hydrogen ion concentrations are restored to normal levels.

What is osmosis?

*Osmosis* is the net diffusion of a solvent from a solution of lesser to one of greater solute concentration that are separated by a selectively permeable membrane. Within body fluids, the solvent is water. Thus, biologists consider osmosis to be the net diffusion of water through a selectively permeable membrane. The force of the water movement across the membrane is called the *osmotic pressure*. The osmotic pressure depends on the number of particles present on either side of the membrane; the more particles, the higher the osmotic pressure developed. Osmotic pressure is dependent on the number of active particles in solution. When placed in solution, a mole of an electrolyte will create more osmotic pressure than a mole of non-electrolyte because the electrolyte will dissociate into its constituent ions, each an osmotically active particle. As stated before, the driving force for diffusion is a concentration gradient. The driving force for osmosis is the osmotic pressure. However, if you look at the osmotic pressure formula closely, you will see that the osmotic pressure (the driving force for osmosis) is very dependent upon the concentration gradient.

Under what conditions are phosphates observed in urine?

*Phosphates* are derived chiefly from food and are also produced in small amounts during cellular metabolism. Large amounts of calcium phosphate are found in bone. Thus, in bone demineralizing diseases, such as *rickets, osteomalacia, or osteoporosis*, there is an increase in the renal excretion of phosphates.

What is secretin?

*Secretin* is released by cells deep in the mucosal glands located in the upper portion of the small intestine. Secretin increases the secretion of bicarbonate by the duct cells of the pancreas and biliary tract. It is responsible for the secretion of a watery, alkaline pancreatic juice. It also augments the action of CCK in producing pancreatic secretion of digestive enzymes and decreases gastric acid secretion. The secretion of secretin is increased by the products of protein digestion and by acid bathing the mucosa of the upper small intestine. Because of the release of an alkaline pancreatic juice, the acid from the stomach is neutralized. This neutralization stops the further secretion of secretin.

What is tonicity?

*Tonicity* is defined as the osmotic pressure or tension of a solution, usually relative to the blood. Fluids which contain osmotically active particles in the same concentration as found in the plasma of the blood are said to be *isotonic*. Isotonic implies that the solution will produce no change in cell size due to water movement in or out of the cell. If a human blood cell is placed in an isotonic solution, it neither shrinks nor swells since the net diffusion of water into and out of the cell is zero. A 0.3 Molar solution of a nonelectrolyte such as glucose is isotonic to mammalian cells, as is a 0.9% solution of sodium chloride (an electrolyte). Fluids which contain a higher concentration of osmotically active particles than blood plasma are said to be *hypertonic*. Red blood cells which are placed in a hypertonic solution will shrink (*crenate*), since there is net diffusion of water out of the cells. *Hypotonic* solutions contain a lower concentration of osmotically active particles than does the plasma, and thus produce a lower osmotic pressure than within the red blood cell. Therefore, the red blood cells will swell and burst (*lyse*) when placed in hypotonic solutions since the net diffusion of water will be into the cell.

What are tubular secretion and reabsorption?

*Tubular secretion* is the selective movement of molecules from the peritubular capillaries into the tubules. This process can allow certain molecules to be removed from our blood more quickly than if filtration alone were responsible for removing substances from our blood. *Tubular reabsorption* is the selective movement of molecules from the tubular lumen into the peritubular capillaries. Tubular reabsorption of specific molecules is thoroughly regulated by a number of hormones. Regulation of tubular reabsorption allows us to maintain fine control over out internal fluid environment, and is thus of extreme importance in maintaining homeostasis.

What are the 3 ways diabetes can be diagnosed?

1) Blood glucose >126 mg% 2) OGTT over 200 mg% after 2 hours 3) Hemoglobin A1C

How are proteins digested?

1) Dietary and endogenous proteins are hydrolyzed to their constituent amino acids and a few small peptide fragments by gastric pepsin and the pancreatic proteolytic enzymes. 2) Amino acids are absorbed into the small-intestine epithelial cells and eventually enter the blood by means of Na+ and energy-dependent secondary active transport. Various amino acids are transported by carriers specific for them. 3) The small peptides, which are absorbed by a different type of carrier, are broken down into their amino acids by aminopeptidases in the epithelial cells' brush borders or by intracellular peptidases.

How are carbohydrates digested?

1) The dietary polysaccharides starch and glycogen are converted into the disaccharide maltose through the action of salivary and pancreatic amylase. 2) Maltose and the dietary disaccharides lactose and sucrose are converted to their respective monosaccharides by the disaccharidases (maltase, lactase, and sucrase) located in the brush borders of the small-intestine epithelial cells. 3) The monosaccharides glucose and galactose are absorbed into the interior of the cell and eventually enter the blood by means of Na+ and energy-dependent secondary active transport. 4) The monosaccharide fructose is absorbed into the blood by passive facilitated diffusion.

What are the principal actions of insulin on the liver?

1. Decreased cyclic AMP 2. Decreased ketogenesis 3. Increased protein synthesis 4. Increased lipid synthesis 5. Decreased glucose output (decreases gluconeogenesis and increases glycogen synthesis)

What are the principal actions of insulin on adipose tissue?

1. Increased glucose uptake 2. Increased fatty acid synthesis 3. Increased glycerol phosphate synthesis (necessary to form triglycerides) 4. Increased triglyceride deposition 5. Activation of lipoprotein lipase (allowing for increased fatty acid uptake) 6. Inhibition of hormone-sensitive lipase (which decreases breakdown of triglycerides) 7. Increased K+ uptake

What are the principal actions of insulin on muscle?

1. Increased glucose uptake 2. Increased glycogen synthesis 3. Increased amino acid uptake 4. Increased protein synthesis 5. Decreased protein catabolism 6. Decreased release of gluconeogenic amino acids 7. Increased ketone uptake 8. Increased K+ uptake

What are the blood glucose levels you should know?

<50 mg%: hypoglycemia, nervous system dysfunction (sweating, heart racing, light-headedness) 60-100 mg% fasted state, FBG, normal subejcts >100 fasting, pre-diabetes, increased risk for coronary artery disease >126 fasting, diabetes mellitus (7 mM) > 200 OGTT, 2 hours after consuming solution, >200 mg% indicative of diabetes mellitus

What are the brain centers responsible for blood pressure control?

A *vasomotor center* in the *medulla oblongata* (which is located in the *brain stem*) transmits signals through the sympathetic nervous system.

How are the kidneys related to hypertension?

90-95% of all cases of hypertension are primary (or essential) hypertension, in which there is no precisely known cause. In all cases of primary hypertension there is an increase systemic vascular resistance, and in some cases an increase in cardiac output. However, for the high pressures in hypertension to be maintained, there must be a failure of pressure natriuresis to return blood pressure back to normal. It is now clear that the relationship between pressure and sodium excretion is shifted in chronic hypertension so that a higher pressure is required to achieve a given level of sodium excretion. Thus, the elevated blood pressure is accompanied by greater *sodium load* in the body (total amount of sodium in the body) an an increase in blood volume.

What is hypocapnea?

A decreases in the carbon dioxide concentration in the blood (below normal levels).

What is atelectasis?

A general term used to describe partial or total collapse of a lung. Causes include stab or gun show wounds that allow air to enter the pleural cavity, excessive secretions or compression caused by tumors, and other causes.

What is the glucose tolerance test?

A glucose tolerance test is often performed in the diagnosis of diabetes mellitus. The oral glucose tolerance test is commonly used because it is easy and simple to administer. The test includes a 3 day regular mixed diet of at least 250 grams of carbohydrate prior to the test, an overnight fast following the third day, blood and urine samples tested for glucose prior to the test on the fourth day, an ingestion of 80-100 grams of glucose, and measurement of blood and urine samples for glucose at 30, 60, 90, 120, 150 and 180 minutes after ingestion. A normal glucose tolerance test would show elevated blood glucose of about 150 mg/dL after 60 minutes, 140 mg/dL after 90 minutes and then dropping to about 80 mg/dL by 120 minutes. There would normally be no glucose in any of the urine samples.

What is the modified tilt test?

A tilt test can be used to determine if a subject has orthostatic hypotension or if a subject has lost significant amounts of blood of if they are dehydrated. The modified tilt test is performed by taking the subject's seated blood pressure (ideally in a real seated position with a normal chair) and then having them stand up. Start the stop watch or note the time when they stand up. Then, take their heart rate and blood pressure 1 minute after standing up. Unique cutoff points indicating that the subject is "tilt positive" (they have lost significant amounts of blood and/or are dehydrated) if heart rate increases by 20 bpm or if SBP decreases by more than 20 mmHg. However, these cutoffs are considered by some to be too conservative, and it is fairly common for army medics and military medical personnel to use cutoffs of a 10 bpm increase in HR and/or a 10 mmHg decrease in SBP as cutoffs for a "tilt positive" test. If HR increases less than 10 bpm and/or if SBP decreases by less than 10 mmHg we will consider the subject "tilt negative" (normal, not dehydrated, no/insignificant blood loss). This test also demonstrates the function of the baroreceptors and the baroreflex.

What is a spirogram?

A typical spirogram reports the volume of air moved by the lungs on the y-axis and the time it takes to move this air on the x-axis. The information obtained from a spirogram is very useful in assessing possible obstructive or restrictive pulmonary limitations. Both obstructive and restrictive pulmonary diseases can several reduce one's ability to perform exercise, or for that matter, perform their daily tasks. Therefore, it is important for health professionals to understand some of the basic problems associated with obstructive and restrictive disorders and how they are diagnosed.

What is anoxia?

Absence of oxygen in inspired gases, arterial blood, or tissues.

How do pulmonary volumes and capacities differ?

All the pulmonary volumes and capacities are about 20-25% lower in women than men, and tend to be greater in elite athletes and in large persons than in small or inactive individuals.

What is the diabetic curve?

An elevated curve most commonly occurs with diabetes mellitus but may also occur with myasthenia gravis, hyperthyroidism, severe liver damage, emotional stress, and Cushing's disease. A depressed curve may occur in conjunction with tumors of the pancreatic islets, hypothyroidism, Addison's disease, lower than normal functioning ofthe adenohypophysis, and diseases characterized by poor gastrointestinal absorption of carbohydrates. Note the diabetic's hyperglycemic response in blood glucose level and then the very slow drop back to the fasting level (5-6 hours). This abnormal response demonstrates the inability of the pancreas to secrete additional insulin when needed. The normal person's shows elevated blood glucose initially (1 hour) but then falling back to normal within 3 hours or even below fasting levels because of excess insulin release by the pancreas (insulin rebound effect).

What is tachypnea?

An increase in respiratory rate; rapid breathing.

What is hypercapnia?

An increase in the carbon dioxide tension in the body fluids results in stimulation of the medullary respiratory centers. Stimulation of respiratory rate and depth due to elevated partial pressure of carbon dioxide is caused by the increase of hydrogen ions in the cerebral spinal fluid due to the increase in carbon dioxide. Pulmonary ventilation will increase until carbon dioxide levels and the extracellular pH return to normal. Increases in the carbon dioxide level (*hypercapnia*) and hydrogen ion content of arterial blood also stimulate respiration by way of the chemoreceptor mechanisms of the aortic and carotid bodies.

What is alveolar volume?

As previously stated, not all of the air inspired reaches the alveoli because of the anatomical dead space. *Alevolar volume (Va)* or volume of air reaching the alveoli per minute can be calculated as: Va = (TV - 150) X RR

In what other ways can renal hypertension occur?

As we age, we tend to see a reduction in the total number of functioning nephrons in the kidneys (approximately 10% reduction per decade beyond age 40; approximately 30% reduction in nephron number by age 70). The incidence of hypertension increases as we age, and this age-related increase in blood pressure could be due, at least in part, to a failure to be able to clear sodium from the circulation as well as before (need a higher pressure to achieve a given level of sodium excretion). In obesity, there is an increase in renal sympathetic nerve activity. This decreases renal blood flow, and thus reduces GFR and sodium clearance. This is one of the mechanisms by which obesity may result in chronically elevated blood pressure (hypertension).

Why is glucose not normally present in the urine?

As we observed in the renal physiology lab, glucose is not usually present in the urine. However, when blood glucose exceeds the *renal threshold* for reabsorbing glucose, some glucose will be present in the urine, this is called *glucosuria*. This glucosuria has an osmotic effect which will tend to draw excess water with it, leading to excessive urination, a condition called *polyuria*. This excessive fluid loss may lead to dehydration. Diabetes mellitus is also a major health risk for both acute and chronic conditions. Chronic diabetes mellitus is a major risk factor for the development of coronary *atherosclerosis*, ultimately leading to *Coronary Artery Disease (CAD)*.

Are the lungs fully utilized during normal activity?

At rest the amount of air moving in and out of the lungs is much less than the volume of air which the lungs are capable of holding. During heavy exercise, the volume of air is much greater than at rest and this volume may nearly equal the lung capacity. This means the lungs are not fully utilized during normal activity, and that there is a "reserve" volume which may be used during greater workloads. To distinguish between the various types of breathing employed, functional volumes of the lungs have been defined. These static lung volumes can be used to evaluate the status of a patient or athlete.

What are the vascular components of the nephron?

At rest, the kidneys receive about 25% of the total cardiac output. This fact emphasizes the importance of the kidneys for waste removal and regulation of water and electrolytes. Blood enters the kidney by way of renal arteries. Near the hilus, the *renal artery* divides into several branches which divide into even smaller branches. These arteries give rise to several afferent arterioles. The capillary networks, of the glomerulus, form from the afferent arterioles. The efferent arteriole takes blood away from the glomerular capillaries and branches into another network of capillaries surrounding the proximal and distal tubules called *peritubular capillaries*. Long, thin-walled loops of peritubular capillaries called *vasa recta* may also pass into the medulla. The vasa recta are extensions of the efferent arteriole that run parallel to the loop of Henle and the collecting ducts and play a role in the concentration of urine. The peritubular capillaries and the vasa recta drain into veins which join to form a single *renal vein*

What is the residual volume?

At the end of a maximal expiration, some air still remains in the lungs. This volume remains because the mechanical limits of expiration have been reached and no further reduction in the thoracic cavity can occur. This remaining volume is called the *residual volume*.

What is apnea?

Cessation of the breathing process.

How are fats digested?

Because fat is not soluble in water, it must undergo a series of transformations in order to be digested and absorbed. 1) Dietary fat in the form of large fat globules composed of triglycerides is emulsified by the detergent action of bile salts into a suspension of smaller fat droplets. This lipid emulsion prevents the fat droplets from coalescing and thereby increases the surface area available for attack by pancreatic lipase. 2) Lipase hydrolyzes triglycerides into monoglycerides and free fatty acids. 3) These water-insoluble products are carried in the interior of water-soluble micelles, which are formed by bile salts and other bile constituents, to the luminal surface of the small intestine epithelial cells. 4) When a micelle approaches the absorptive epithelial surface, the monoglycerides and fatty acids leave the micelle and passively diffuse through the lipid bilayer of the luminal membranes. 5) The monoglycerides and free fatty acids are resynthesized into triglycerides inside the epithelial cells. 6) These triglycerides aggregate and are coated with a layer of lipoprotein to form water-soluble chylomicrons, which are extruded through the basal membrane of the cells by exocytosis. 7) Chylomicrons are unable to cross the basement membrane of blood capillaries, so instead they enter the lymphatic vessels, the central lacteals.

What are the effects of increased insulin?

Because insulin increases glucose uptake by most cells in the body, insulin secretion tends to decrease *blood glucose* concentrations. In excess, insulin can cause low blood glucose (*hypoglycemia*) which can cause convulsions and coma. This can arise if a type I diabetic injected more insulin than necessary, and is sometimes referred to as *insulin shock*.

What is digestion?

Before nutrients can be absorbed by the mucosa of the GI tract, food must first be broken down (degraded) into chemically less complex molecules. Carbohydrates are broken down from *polysaccharides* (starch) into their component *monosaccharides*. Proteins are degraded into component amino acids, and lipids are degraded into glycerol and fatty acids. Digestion, therefore, involves the progress of the degradation of complex molecules into simpler molecules. Digestion is catalyzed by the actions of several enzymes secreted into the lumen of the alimentary canal. Digestive enzymes function by catalyzing the *breakdown of the covalent bonds* that hold the digested materials together. Thus, breaking the bonds subdivides the molecule into smaller (simpler) components (molecules). Digestive enzymes all work by catalyzing the *hydrolysis* of these larger molecules into smaller molecules.

What is bile?

Bile is excreted by the liver into the duodenum via the biliary duct system (hepatic ducts, cystic duct and common bile duct). The *gallbladder* is attached to the biliary duct system via the cystic duct. The gallbladder acts as a storage site for bile until it is needed in the duodenum. The cystic and hepatic duct join to form the common bile duct. Immediately before the common bile duct empties into the duodenum, it is joined by the main pancreatic duct. The exocrine portion of the pancreas secretes a number of digestive enzymes, as well as large amounts of sodium bicarbonate, a nonenzyme which acts as a buffer to the hydrochloric acid from the stomach.

How are the pancreatic enzymes activated?

CCK works on acinar cells of pancreas, so the pancreas secretes trypsinogen, chymotrypsinogen and procarboxypeptidase at same time. Enteropeptidase converts trypsinogen to trypsin. Trypsin then converts chymotrypsinogen to chymotrypsin and procarboxypeptidase to carboxypeptidase.

What is emphysema?

Condition where the alveoli become distended with trapped air. Lung elasticity is reduced and the alveolar walls degenerate so that the air sacs are increased and there is a reduction in functional alveoli. The chest becomes enlarged and barrel-shaped. There is an increase in airway resistance that makes exhalation difficult. Caused by infectious agents; seen in chronic smokers.

What is hypoxia?

Decrease below normal levels of oxygen in air, blood, or tissues.

What is blood glucose regulation?

Decrease of glucose concentration in the blood -> stimulates alpha cells -> secretes glucagon -> glycogenolysis (breaks down glycogen) + gluconeogenesis (glucose from amino acids, lactate, glycerol) -> increases plasma glucose level -> stimulates beta cells in islets -> secretes insulin -> stimulates glycogenesis (formation of glucose to glycogen) and increase cell uptake of glucose -> decrease in plasma glucose level

How does liver disease affect filtration?

Decreased colloid osmotic pressure -> increased filtration High blood pressure: increased capillary blood pressure -> increased filtration

What is the diving reflex?

Decreased heart rate caused by PNS Benefit? Heart uses less oxygen Mean arterial pressure increases: vasoconstriction of arterioles, less oxygen used by tissues Brain and heart most important Receptor: thermoreceptors Afferent nerves: trigeminal nerve Increased apnea -> increased response

What are the effects of decreased insulin?

Deficiency of insulin secretion or insulin action causes *diabetes mellitus*, a potentially fatal disease characterized by hyperglycemia, *glucosuria*, accelerated lipid and protein metabolism, *ketoacidosis*, acetone breath, *polyuria* (increased urine flow), *polydipsia* (excessive thirst), *polyphagia* (excessive eating), and in some cases, paradoxically, *hyperinsulinemia* (elevated blood insulin levels).

What is diabetes mellitus?

Diabetes mellitus is, unfortunately, a very common endocrine disorder. Diabetes mellitus is characterized by inadequate insulin action, which results in hyperglycemia. Clinically, diabetes mellitus is defined by having a fasting blood glucose concentration of over 126 mg/dL (or 7 mmol/L). There are two types of diabetes mellitus. *Type I*, or *insulin-dependent diabetes mellitus* is characterized by insufficient insulin secretion due to the destruction of the insulin-producing beta-cells of the pancreas. In *Type II*, or *non-insulin-dependent diabetes mellitus*, insulin's target cells are less sensitive to insulin (the cells are said to be *insulin resistant*). The exact cause of this insulin resistance is unknown. However, most of the research literature suggests that the problem lies in the cell's intracellular signaling pathways.

What is asthma?

Difficulty in breathing caused by a spasm or constriction of the bronchioles. Allergens in the air that are inhaled into the lungs cause most of the asthmatic attacks.

What is the digestive system?

Digestion is the process that converts ingested food into material suitable for assimilation for the synthesis of tissues (anabolism) or the liberation of energy (catabolism). The human digestive system consists of the *alimentary canal* and the *accessory organs*. The function of the digestive system is controlled by the autonomic nervous system;the parasympathetic nervous system speeds up the function of the digestive system and the sympathetic nervous system slows it down.

What is tidal volume?

During normal quiet breathing the lung expands from the midpoint to a somewhat larger volume and then returns to the midpoint. This volume taken in and expired is known as the *tidal volume*. Tidal volume averages about 500 mL in adults.

What is the anatomy of the kidney?

Each bean-shaped kidney has two borders: the lateral border is convex and the medial border is concave. At the medial border is an indentation known as the *hilus* where the ureter exits the kidney and the renal vessels, lymphatics, and nerves communicate with the kidney. Internally, the hilus opens into a space called the *renal sinus*. This sinus contains the *renal pelvis* and the renal vessels. There are two main regions of the kidney - an outer reddish region known as the cortex and an inner reddish-brown area known as the medulla. The medullary region contains 5-18 structures called renal pyramids. Each pyramid's base is at the cortical end and its apex is at the internal (medullary) end. The pyramids are separated from one another by continuations of the cortex called renal columns. The apex of each pyramid leads into a small tube known as a minor calyx. Several minor calyces join together to form a major calyx. The major calyces then converge to form a large cavity called the renal pelvis. It is the renal pelvis that beings to taper near the hilus and narrows to become the ureter. Urine, having been formed, travels this minor calyx-major calyx-renal pelvis route to the urinary bladder via the ureter.

What are vasoconstrictors you should know?

Epinephrine Norepinephrine Vasopressin (ADH) Angiotensin I and II Ca++ Decreased temperature

What is the valsalva maneuver?

Exhale against a closed glottis (not very long) Increased pressure in thoracic cavity -> increased pressure on aorta and arteries -> MAP elevated Harder to return blood to heart if pressure is high -> decreased venous return -> decreased heart rate

What is the cold pressor reflex?

Extreme cold can stimulate temperature sensitive nociceptors and therefore cause pain. In general, painful stimuli initiate fight or flight responses. The normal reflex response to a cold stimulus (or painful stimulus) is an increase in blood pressure (both systolic and diastolic). This occurs because the cold stimulus produces an overall systemic vasoconstriction, which elevates blood pressure. In normal subjects, the increase in blood pressure is detected by the baroreceptors, which reflexively bring about a lowering of blood pressure to compensate for the rise. If the baroreceptor reflex is working normally, the rise in blood pressure with cold will be held to 10 mmHg. A hypertensive individual may experience a rise in blood pressure as high as 30 to 40 mmHg.

What is forced expiratory volume in one second (FEV1)?

FEV1 can also be expressed as a percent of total vital capacity expired during the entire expiratory period (FEV1/VC x 100), this is called the *FEV1/VC ratio*. A normal person should be able to forcefully exhale 80% of VC in 1 second, 94% of VC in 2 seconds, and 97% of VC in 3 seconds.

What is the function of vasopressin?

Fine control over the reabsorption of water in the kidney is regulated by the hormone *vasopressin* (VP, also known as *antidiuretic hormone*, ADH, also sometimes AVp, arginine vasopressin). ADH functions to regulate water balance in the body by increasing tubular permeability (to water) of the collecting tubules and thus, increasing the amount of water reabsorbed. The more ADH present in the kidney, the greater the permeability of the distal and collecting tubules to water. This is due to mobilization of *aquaporins* to the epithelial cell membranes. Upon binding with its receptor, ADH increases *cAMP* production and signals the translocation of aquaporin vesicles to the membrane. ADH is produced by the supraoptic nuclei of the hypothalamus and is stored and released by the posterior pituitary (neurohypophysis). ADH-producing cells act as osmoreceptors (cells that are sensitive to changes in extracellular osmolarity), so that when osmolarity decreases, ADH secretion decreases and *when osmolarity increases, ADH secretion increases.* Vasopressin plays an important role in regulation of blood pressure; both by its role in regulating ECF volume, and by actin as a vasoconstrictor.

What are the forces involved in glomerular filtration?

Glomerular capillary blood pressure: favors filtration Plasma-colloid osmotic pressure: opposes filtration Bowman's capsule hydrostatic pressure: opposes filtration Net filtration pressure: Favors filtration

What are inhibitors of glucagon?

Glucose (hyperglycemia) Somatostatin Secretin Free fatty acids Ketones Insulin Phenytoin Alpha-adrenergic stimulators

What are stimulators of insulin?

Glucose (hyperglycemia) Manose Amino acids Intestinal hormones (GIP, gastrin, secretin, CCK, glucagon) Beta-Keto acids Acetylcholine Cyclic AMP and various cyclic AMP-generating substances Beta-adrenergic stimulating agents Theophylline Sulfonylureas

How does glucose get across cell membranes?

Glucose is delivered to cells via blood in the capillaries, but because it is a larger molecule that requires a membrane transport molecule (glucose transporter, *GLUT*) to get across the membrane (via carrier-mediated transport) it enters the cell more slowly. Some cells, like those in the tubules of the kidney and the brain, have GLUT molecules (GLUT1 and GLUT3) that are always present in the membranes (and thus not subject to regulation). However, the type of GLUT molecules in skeletal muscle and adipose tissue, *GLUT4*, are subject to regulation by insulin, and in the case of muscle, by muscle contraction. Under resting conditions, the muscle cells take up very little glucose, because there are not very many GLUT4 molecules in the muscle cell membrane (*sarcolemma*). But the hormone insulin, which is secreted by the pancreas when there is an increase in blood glucose (such as after a meal), causes an increase in muscle glucose uptake by increasing the number of GLUT4 molecules in the membrane. The translocation of vesicles of GLUT4 from the interior of the cell to the membrane can also be caused by exercise.

What are the critical cardiovascular relationships you must know?

HR = 60/RR interval SV (mL/beat) = EDV - ESV MAP (mmHg) = 1/3PP + DBP MAP (mmHg) = Q x TPR R = nL8/pi^4 Q (L/min) = SV x HR EF% = SV/EDV PP = SBP - DBP RPP = HR x SBP EDV is especially influenced by factors that influence *venous return* (e.g. muscle pump, respiratory pump, cardiac suction, venoconstriction, blood volume, among others).

What are vasodilators you should know?

Histamine K+ Na+ Magnesium Increase temperature Increase H+ (low pH) Increased carbon dioxide concentration Acetylcholine ADP Nitric Oxide (NO, EDRF)

What is insulin shock?

If insulin causes the blood glucose levels to fall to low values, the central nervous system becomes depressed. In patients with hyperinsulinism or in diabetics who administer too much insulin to themselves, the condition known as *insulin shock* may occur. As the blood glucose level falls into the 50-70 mg/dL range, the central nervous system usually becomes very excitable due to hypoglycemia at this range facilitating neuronal activity. Symptoms at this level may include extreme nervousness, trembling, sweating, and even hallucinations. With blood glucose falling to the 20-50 mg/dL level, clonic convulsions and loss of consciousness are likely to occur. As the glucose level decreases still lower, the convulsions cease, and only a state of coma remains. It is sometimes difficult to distinguish between *diabetic coma* as a result of the lack of insulin and coma due to the hypoglycemia caused by excess insulin. In hypoglycemic coma (insulin shock), the acetone breath and the rapid deep breathing of diabetic coma are not present. If treatment (i.e. by intravenous administration of glucose or administration of glucagon) is not done immediately, permanent damage to the neuronal cells of the central nervous system occurs.

What occurs in hyperventilation?

If respiration is increased above the body's metabolic demands (*hyperventilation*), the lungs rid the body of carbon dioxide faster than it is produced, thus decreasing the hydrogen ion concentration in the circulation, causing the pH to increase. This tends to depress respiration until carbon dioxide levels and hydrogen ion levels are back to normal. The temporary cessation of breathing after voluntary hyperventilation is called *apnea vera*. With hyperventilation, one often gets dizzy or light-headed. Carbon dioxide is a major vasodilator of cerebral blood vessels. With the lowering of carbon dioxide in the blood due to the hyperventilation, there is a resultant vasoconstriction in the brain which reduces blood flow and creates the light-headed feeling.

Under what conditions are ketone bodies observed in urine?

If there is *excessive fat metabolism*, one may see greater than trace amounts of *ketone* bodies such as acetic acid and beta-hydroxybutyric acid in the urine. This can be due to a high dietary fat intake or a dependence on fat metabolism for energy production because of a lack of glucose uptake (such as in *diabetes mellitus*).

What is the inspiratory reserve volume?

If we inspire as much air as we can, the lung is expanded much more than it is in normal respiration. The extra volume taken in above tidal volume following a maximal inspiration is called the *inspiratory reserve volume*.

Why did we test vital capacity?

If your subject's measured VC is less than 80% of predicted VC, we will take this as evidence that the subject has a *restrictive pulmonary disease*.

What is asphyxia?

Impaired or absent exchange of oxygen and carbon dioxide on a ventilatory basis.

What are the functions of the endocrine pancreas?

In addition to the exocrine functions utilized by the digestive system, the *pancreas* secretes two important *endocrine* hormones, *insulin* and *glucagon*. The islets of Langerhans within the pancreas are responsible for their secretion. Insulin is secreted by the *beta cells* and glucagon is secreted by the *alpha cells*. The concentration of glucose in the blood is generally regulated within a normal range of 70-100 mg/dL by these hormones.

What is the threshold value?

In addition to water and ions, many other substances such as amino acids, urea, and glucose are filtered into the glomerular capsules. As the filtrate passes through the nephron, most of the constituents are reabsorbed to varying degrees depending on the body's need to maintain homeostasis. In addition, some substances (e.g. hydrogen ions, potassium, and drugs) are actively secreted by renal tubular cells into the urine. Certain substances in the blood do not appear in the urine until their concentration exceeds a certain critical level: the *threshold value* for that substance. An example of a substance that has such a threshold level is glucose. For this reason, sugar normally does not appear in the urine. Colloidal material and substances of high molecular weight (e.g. plasma proteins, red blood cells, white blood cells, etc.) are normally absent from the filtrate.

Under what conditions is albumin observed in urine?

In many *renal diseases* an in one benign condition, protein is found in the urine in more than trace amounts. Various types of nephrosis and nephritis may cause abnormal leakiness and/or severe damage to the glomerular membrane (i.e. increased permeability of the glomerular capillaries). Most of this protein found in the urine is *albumin*, and the defect is known as *albuminuria*. A poorly understood benign condition called orthostatic albuminuria occurs in otherwise normal people. Albumin is found in their urine only when they are standing.

What is usual composition of urine?

In the 1500 mL/ day (approximately 50 ounces per day) of urine produced by an average 70 kilogram adult, one would find approximately 60 grams of solids (approximately 0.13 pounds). These solids would consists of: urea (30 grams), sodium chloride (15 grams), and 15 grams of various organic and inorganic substances such as creatinine, amino acids, uric acid, ammonia, sulfates, phosphates, potassium and magnesium. Under unusual and/or pathological conditions, other substances normally absent or present only in trace amounts may be detected. Blood cells, hemoglobin, proteins, glucose, ketone bodies, and bile fall in this group.

Under what conditions is glucose observed in urine?

In the kidney, glucose is freely filtered by the glomerulus but normally all except trace amounts are reabsorbed in the proximal convoluted tubules. Glucose reabsorption is an active process requiring energy and involving a carrier-mediated transport system in the tubular cell. There is a limit to the amount of glucose the proximal convoluted tubules can reabsorb. When the *tubular maximum* for glucose is exceeded, glucose begins to appear in the urine (*glucosuria*). This plasma threshold amount is approximately 180 mg/dL. The normal glucose level in the blood ranges from 60 to 120 mg/dL, well below the *renal threshold* for glucose. In cases such as *diabetes mellitus*, adrenal diabetes, and excessive sugar dietary intake, glucose levels are higher than the normal range (*hyperglycemia*), and glucosuria will result if the renal threshold is exceeded. There is also a benign, genetic abnormality known as renal glucosuria that allows for glucose to be excreted at a normal blood glucose concentration because of a reduced ability of the proximal convoluted tubules to transport glucose.

What is diabetes insipidus?

Individuals with *diabetes insipidus* do not secrete sufficient vasopressin, and thus do not reabsorb enough water. Urine volume in diabetes insipidus can reach 20 liters per day (normal urine output per day is around 1.5 L/day).

What is pneumonia?

Inflammation of the lungs with accumulation of fluids in the alveolar spaces. It is caused by a variety of bacteria, viruses, irritants, and allergies.

What is pleurisy?

Inflammation of the pleural membranes caused by a variety of infectious organisms.

What is insulin?

Insulin is a 5.81 kilodalton (kD) peptide hormone composed of two amino acid chains. It has an effect on the metabolism of carbohydrates, fats, and protein. An increase in concentration of glucose in the blood (*hyperglycemia*) causes a rapid secretion of insulin. One of the most important of all the effects of insulin is the rapid uptake of glucose and storage as *glycogen* by the liver and muscle. Extra insulin in the blood causes rapid uptake of glucose into muscle cells. Insulin also increases fatty acid and protein synthesis. In general, the principal actions of insulin are the uptake of fuel substrates and the storage of these fuel substrates. The mechanisms by which insulin cause these actions are very complex, involving the insulin receptor and a large number of signaling molecules.

What are the components of lipids?

Lipids (fats) are made up of two different kinds of building blocks- *glycerol* and *fatty acids*. When one glycerol molecule combines with three fatty acid molecules, a neutral fat known as a *triglyceride* is formed. Compound lipids (e.g. phospholipids, glycolipids, lipoproteins) are developed from various combinations of triglycerides with other components. Mucosal absorption occurs in the process of lipid digestion only after fats are broken down into component glycerol and free fatty acids.

What is the difference between obstructive and restrictive pulmonary diseases?

Lung capacities and volumes are generally reduced in restrictive pulmonary diseases. In obstructive pulmonary diseases, there is generally a reduction in airflow. Obstructive and restrictive pulmonary diseases often occur together.

How do you calculate predicted vital capacity?

Males: VC = 0.052 H - 0.022 A - 3.60 Females: VC = 0.041 H - 0.018 A - 2.69 VC = vital capacity in liters H = height in centimeters A = age in years

What are the components of the alimentary canal?

Oral cavity Pharynx Esophagus Stomach Small intestine -Duodenum -Jejunum -Ileum Large intestine -Cecum and appendix -Ascending colon -Transverse colon -Descending colon -Sigmoid colon Rectum Anal canal

How is dietary fat absorbed?

Most of the dietary fat is in the form of triglycerides. *Triglycerides* are made up of three *fatty acids* attached to a molecule of *glycerol*. The differences in the dietary fats are mostly dependent on the types of fatty acids present in these triglycerides. Triglycerides can not be absorbed. However, triglycerides are broken down into monoglycerides and free fatty acids, which can be absorbed. The breakdown of triglycerides is called *lipolysis*. Within the intestinal lumen, the free fatty acids and monoglycerides become dissolved in the lipid portion of bile acid aggregates called *micelles*. By way of the micelles, the fatty acids and monoglycerides are transported to the surfaces of the microvilli. The fatty acids and monoglycerides diffuse through the villi's epithelial membrane due to the lipid properties of the membrane. The bile acid micelles remain in the lumen where they can diffuse through the chyme and bind more monoglycerides and fatty acids. Once inside the epithelial cell, the fatty acids and monoglycerides are taken up by the cell's endoplasmic reticulum where they are recombined to form triglyceride globules. These globules, called *chylomicrons*, diffuse to the side of the epithelial cells where by exocytosis they are excreted into the space between the cells. From these spaces, the chylomicrons pass into the lymph of the *central lacteals* of the villi. From the lacteals, lymphatic vessels carry the chylomicrons to the venous blood of the left subclavian vein via the thoracic duct. The digestion of fat is performed by the enzyme *lipase*. Intestinal and pancreatic (pancreatin) lipase are assisted in their digestive role by the emulsifying action of bile.

What is the relationship between exercise and insulin?

Most tissues are dependent on insulin for glucose uptake from the blood. At rest this is exactly the same case for skeletal muscle. However, during exercise, glucose uptake by the skeletal muscle is non-insulin dependent (no insulin is required for the muscle cells to take up glucose). This is demonstrated by the fact that during an acute bout of exercise, blood glucose remains relatively constant in spite of a dramatic decrease in circulating insulin. It has been demonstrated that exercise training improves blood glucose control by increasing the sensitivity of insulin's target cells to insulin. It has also been demonstrated that the incidence of diabetes is greatly reduced in physically active populations. Thus, exercise is beneficial in both the prevention and treatment of diabetes mellitus.

What is salt-sensitive hypertension?

Most young healthy adults do not have salt-sensitive changes in blood pressure. That is, regardless of how much sodium they consume, they require a similar blood pressure to clear that sodium, and thus experience no chronic increase in blood pressure. However, some individuals do experience *salt sensitive hypertension*. In these cases, an increase in sodium intake results in a sustained increase in blood pressure. Even if most young, healthy individuals are relatively salt-insensitive, large population studies suggest that decreasing sodium intake is one of the best nutritional strategies for reducing blood pressure and the risk of developing hypertension. It is true that humans are obligated to consume some amount of sodium (we have no body stores of sodium), the typical American diet includes far more sodium than necessary, and this excess sodium intake, in turn, increases the risk of developing hypertension.

How do the respiratory centers work together?

See lab 13 page 10

What is the cause of NIDDM?

NIDDM is often associated with chronic overeating, which results in the secretion of excess insulin in order to try to maintain normal blood glucose levels. Over time this chronic hyperinsulinemia and insulin resistance results. This reduced insulin sensitivity will eventually lead to hyperglycemia. With dietary control and/or exercise, blood glucose can be reduced to normal levels, resulting in a decrease in insulin secretion, and thus a possible increase in cellular insulin sensitivity back to normal. The hormone *resistin* was discovered in the last decade and it was through for a time that it could be the causal link between obesity and type II diabetes. Resistin is released by adipocytes (fat cells) and it causes other cells in the body to become resistant to the actions of insulin (reduces the ability of insulin to cause an increase in glucose uptake). Thus it is possible that obesity would increase the number or size of adipocytes, resulting in increased secretion or resistin, and thus causing a global decrease in the subject's insulin sensitivity.

What is eupnea?

Normal, quiet breathing.

What are glycemic index and glycemic load?

Not all foods result in the same glycemic response (tendency to increase blood glucose), even if they have the same amount of carbohydrate. The glycemic index represents the tendency of a given food to increase blood glucose compared to a standard food (either glucose or white bread). Those foods that cause a large and/or rapid rise in glucose are referred to as being *high glycemic index foods*. These include white bread, potatoes, white rice, puffed cereals, sugary foods. Whole grains and many fruits and vegetables do not result in as rapid, or as large a rise in blood glucose and are thus considered *low glycemic index foods*. The amount of carbohydrate also makes a difference. The *glycemic load* is determined by both the GI and the total amount of carbohydrate. The more carbs and/or the higher the GI, the greater the blood glucose response to eating will be.

How do the kidneys regulate osmolarity, volume and pressure?

One important function of the kidney is to regulate the osmolarity of the body fluids. When the normal constituents of the blood, such as salts, glucose, and amino acids rise above certain concentrations, they are excreted. When metabolic processes produce excess acid, the urine becomes more acidic. When bases are present, the urine is less acidic. The total volume of blood is also under careful control. When blood volume increases due to a large increase in fluid intake, the urine produce is high in volume and dilute. When the blood volume is low, as when one is dehydrated, the urine is concentrated and urine output decreases.

What is the functional residual capacity?

The sum of the residual volume and the expiratory reserve volume is called the *functional residual capacity*. FRC = RV + ERV

What is the formula for osmotic pressure?

Pi = iRT (C1 -C2) T= absolute temperature, Kelvin pi = osmotic pressure in atmospheres i = the number of ions dissociated from each molecule in solution R = gas constant of 0.082 L*atm/degree*mole (C1 - C2) = concentration gradient in moles per liter; molarity of C1 - molarity of C2

What are the components of proteins?

Proteins are very large, complex molecules. They primarily consist of chains of subunits called L-*amino acids*. There are 20 different naturally occurring amino acids. The type and sequence of amino acids forming the protein give that protein its structural and chemical properties. The component amino acids of a protein are united by *peptide bonds* (i.e. chemical bonds between the alpha carboxyl group of one amino acid and the alpha amino group of the other). A *dipeptide* is when two amino acids unite. Several dipeptides joined together form a *polypeptide*, small chains of amino acids. Polypeptides when united form *peptones*, intermediate-size chains of amino acids, or proteoses, large chains of amino acids. All proteins must be broken down into their component amino acids before the GI mucosa can absorb them.

What is respiratory pathology?

Pulmonary volumes and capacities are generally measured in the clinical assessment of a variety of pulmonary disorders. Chronic pulmonary diseases generally may be classified into two categories: 1) *Obstructive pulmonary disorders* (e.g. bronchial asthma, emphysema) 2) *Restrictive pulmonary diseases* (e.g. pulmonary fibrosis, other chronic diseases of the pulmonary interstitium)

What is Pousielle's Law?

R = nL*8/pi^4

What is blood pressure regulation?

Recall that in general if blood pressure is too low, the body responds by increasing cardiac output (Q) and/or by increasing resistance. If blood pressure is too high the body responds by decreasing Q and/or by decreasing resistance. The immediate responses are mediated primarily by the autonomic nervous system, though local and hormonal factors may also respond fairly quickly. The *sympathetic nervous system* tends to increase blood pressure by increasing cardiac output (Q) and/or by increasing resistance (TPR, by causing vasoconstriction). The *parasympathetic nervous system*, on the other hand, tends to decrease blood pressure by decreasing Q (with no effect on resistance).

How are digestive processes regulated?

Regulation of digestive processes occurs at multiple levels. The digestive and absorptive functions of the digestive system depend upon a variety of mechanisms that soften the food and propel it through the GI tract, and mix it with bile and digestive enzymes (*peristalsis* and *segmentation*). Some of these mechanisms depend upon intrinsic properties of intestinal smooth muscle, while others involve the operation of visceral reflexes or the actions of gastrointestinal hormones. The gastrointestinal hormones help regulate gastrointestinal secretion and motility. The secretion and functions of the four principal gastrointestinal hormones, *gastrin, cholecystokinin, secretin, and gastric inhibitory peptide* are discussed.

How are respiratory rate and depth adjusted?

Respiratory rate and depth are adjusted according to the body's needs. The respiratory centers receive inputs from the higher brain centers (e.g. pons, cerebellum, cerebral cortex) and from peripheral receptors such as chemoreceptors in the aortic and carotid bodies, proprioreceptors in the joints, muscles, and tendons, and somatic sensory receptors for pain and thermal stimuli. Cerebral cortical control (voluntary) of the medullary centers can be observed when there is a modification in the respiratory cycle (change in breathing) as one attempts to perform a precise movement with the hands. Other modifications of the respiratory cycle involve feedback excitation of respiratory center activity in response to changes in the chemical composition of the blood, especially its concentrations of carbon dioxide, hydrogen ions, and oxygen.

How is pulmonary disease diagnosed?

Restrictive pulmonary disease may be diagnosed, in part, by measuring lung volumes and capacities. Usually pulmonary flow rates are needed to detect obstructive pulmonary diseases. Pulmonary function tests have been developed to determine respiratory efficiency (i.e. ability to move air in and out of the lungs). These tests enable one to determine some measure of 1) lung compliance or elasticity, 2) airway resistance, and 3) respiratory muscle strength. These three factors determine how much air a person can move into the lungs per unit time.

What is polypnea?

Shallow rapid breathing.

What is the bicarbonate buffering system?

Since it is continuously being produced during cellular metabolism, carbon dioxide is eliminated by the respiratory system. As the carbon dioxide is formed in the body fluids, some hydrogen ions tend to decrease body fluid pH and stimulate respiration. This buffering mechanism is sometimes referred to as the *bicarbonate buffering system* and is summarized by the formula. The reaction presented is reversible, allowing for hydrogen ions to combine with bicarbonate ions to form carbon acid which can be broken down to water and carbon dioxide for the excretion of carbon dioxide.

How is salt reabsorption regulated?

Sodium chloride is filtered into the glomerular capsule, but much of the filtered sodium can be actively reabsorbed from the tubules. Normal urine, however, contains some salt. Regulation of salt reabsorption is affected, in part, by *aldosterone*, a hormone secreted by the adrenal cortex and atrial natriuretic peptide. *Atrial natriuretic peptide* (ANP) is a hormone that decreases sodium reabsoprtion. This hormone is released fom the cardiac atria primarily in response to an increase in blood volume.

What are inhibitors of insulin?

Somatostatin 2-Deoxyglucose Mannoheptulose Alpha-adrenergic stimulating agents (norepinephrine, epinephrine) Beta-adrenergic blocking agents (propranolol) Diazoxide Thiazide diuretics Phenytoin Alloxan Microtubule inhibitors Insulin Hypoglycemia

What is dead space?

Some of the air that one breathes never reaches the gas exchange areas of the lung but instead goes to fill the respiratory airways. This air is termed *dead space* air because it is not involved in the gas exchange process. The dead space volume for a normal young adult is about 150 mL. This increases slightly with age.

What is glomerular filtration?

Some of the water, ions, and other small molecules within the blood that go through the glomerular capillaries get filtered into Bowman's capsule. This glomerular filtration is ultimately dependent upon the balance of a number of opposing pressures. However, because the glomerular capillary blood pressure (which is ultimately dependent on arterial blood pressure) is greater than the opposing pressures there will be a net positive filtration pressure that favors filtration. The rate of glomerular filtration, the *glomerular filtration rate* (GFR) can be altered by a number of mechanisms. First, the kidneys have an amazing capacity for autoregulation. As previously stated the kidneys usually receive 25% of cardiac output per minute, but blood pressure can change dramatically without much of a change in the glomerular capillary blood pressure. Recall Ohm's law from our blood pressure labs. If blood flow is constant even though the pressure changes, then there must be a change in resistance. Thus, the kidneys can maintain the proper filtration pressure in part by *autoregulation* (self regulation of its own blood flow). The *sympathetic nervous system* can also play a role in determining the GFR by changing the radius of the afferent arterioles that feed blood into the glomerular capillaries.

What is the inspiratory capacity?

The sum of the tidal volume and the inspiratory reserve volume is called the *inspiratory capacity*. IC = TV + IRC

What are the chemical and physicial compositions of normal urine?

Specific Gravity: 1.002-1.045 Color: Light to dark amber Quantity: 800-2300 mL/24 hours Odor: Variable, usually ammoniacal pH: 4.8-7.5 Glcuose: 0.015% Nitrogen: 7-20 grams/24 hours Amino acids: 0.15-0.30 grams/24 hours Ammonia: 0.6-2 grams/24 hours Urea: 12-35 grams/24 hours Creatine: 0.8-2.0 grams/24 hours Uric Acid: 0.3-0.8 grams/24 hours Hippuric acid: 0.7 grams/24 hours Chlorides: 10-15 grams/24 hours Phosphorus: 1.2 grams/24 hours Potassium: 1.5-2.0 grams/24 hours Magnesium: 0.1-0.2 grams/24 hours Sulfur: 1.2 grams/24 hours Sodium: 2.5-4.0 grams/24 hours Calcium: 0.1-0.3 grams/24 hours Vitamins, Hormones, Enzymes: Variable

What is the function of the dorsal respiratory group?

The *dorsal respiratory group* (DRG) functions primarily in the control of inspiration and is generally thought of as the breathing "pacemaker" under resting conditions. The dorsal respiratory group initiates inspiration by stimulating the phrenic nerve, which, in turn, stimulates the diaphragm. However, it is possible that the *pre-Botzinger complex* actually sets the respiratory rhythm. The primary centers (DRG and VRG) are inherently rhythmic. Their activity alternates to produce inspiration and expiration. During normal quiet breathing at rest, the inspiratory center (dorsal respiratory group) acts to produce an active inspiration. The expiratory center limits an then inhibits the inspiratory center to produce a passive expiration.

What kind of receptor is the insulin receptor?

The *insulin receptor* is one of a class of receptors called *tyrosine kinase* receptors. These receptors are also enzymes that are capable of phosphorylating themselves. Once insulin binds with its receptor, the receptor phosphorylates itself, which sets in motion a series of signaling events that, in skeletal muscle, eventually lead to increased glucose uptake (by increasing the number of GLUT4 transporters in the membrane), glycogen storage, amino acid uptake, and protein synthesis.

What is the specific gravity of urine?

The *specific gravity* of a liquid is determined by comparing the weight of a given volume of that liquid to the weight of an identical volume of pure water. By definition, the specific gravity of water is 1.000 and the normal range for urine is 1.010 to 1.030. Higher values for the specific gravity indicate more concentrated urine (less water reabsorption).

What is the function of the ventral respiratory group?

The *ventral respiratory group* (VRG) functions in control of both inspiration and expiration when there is a great ventilatory demand, such as during exercise. During exercise or other situations where the respiratory depth increases, both inspiration and expiration are active processes controlled by their respective medullary centers.

What is respiratory alkalosis??

The H+ ion concentration in blood is below normal due to a drop in the partial pressure of carbon dioxide.

Where does most absorption take place?

The absorption of nutrients from the GI tract occurs mainly in the small intestine. The stomach plays a minimal role in absorption. The stomach has a poor absorptive mucosa due to: 1) the absence of the villi typically associated with absorptive membranes, and 2) the existence of tight junctions between the epithelial cells. Some highly lipid-soluble substances such as alcohol and aspirin can be absorbed by the stomach. Most absorption of water, amino acids, fatty acids, monoglycerides and monosaccharides occurs in the small intestine where the mucosa's microvilli present a large surface area for absorption. While the small intestine absorbs about 90% of the water entering it, the large intestine will absorb most of the remaining water passing from the small intestine. The large intestine also actively absorbs sodium and chloride. Amino acids and monosaccharides are absorbed into the blood of the submucosal vasculatures of small intestines, but the majority of fatty acids and monoglycerides are absorbed differently.

What is vital capacity?

The air expired from maximal inspiration to maximal expiration is called the *vital capacity*. The vital capacity is the greatest volume of air that can be exhaled from the lungs after a maximum inspiration. Vital capacity is sometimes determined with an emphasis on complete inspiration and complete expiration with no emphasis on speed of air movement (*slow vital capacity*), and sometimes when quickly and forcefully expiring (*forced vital capacity*). Whether the maneuver is performed slowly or forcefully, most subjects get similar values (it is the maximal amount of air that can be moved in one breath, regardless of speed). However, in some subjects (e.g. emphysema) air trapping can occur when the subject tries to expire forcefully; and thus FVC is lower than SVC in these subjects.

What is pulmonary (minute) ventilation?

The amount of air moved in and out of the lungs per minute is termed *pulmonary (minute) ventilation*. It is the product of tidal volume and respiratory rate. An individual with a normal tidal volume of 500 mL and a normal respiratory rate of 12-20 breaths per minute would have a Ve of 6-10 liters per minute. Ve = TV x RR

What are conditions that describe the volume of urine?

The average adult voids between 800-2300 mL of urine per day. The elimination of an increased quantity of urine beyond the normal range is called *polyuria*. Polyuria occurs in a number of diseases, such as diabetes mellitus, diabetes insipidus, and chronic nephritis. The elimination of a decreased quantity of urine (*oliguria*) occurs in states such as fever, diarrhea, and thermal stress. In many of these cases, the subject also has excessive thirst (*polydipsia*).

What is glycolysis?

The biochemical pathway that breaks down glucose to pyruvate.

What is the relationship between glucose and the brain?

The brain is quite different from other tissues in that there is a lack of effect of insulin on glucose uptake or use of glucose. Brain cells are permeable to glucose without the intermediation of insulin. The brain cells normally use only glucose for energy. Because of this need for glucose, it is important that blood glucose levels be maintained above a critical level. When the blood glucose decreases into the 20-50 mg/dL range, symptoms of *hypoglycemic shock* develop, characterized by progressive irritability that leads to fainting, convulsions, and even coma.

What is glycogenolysis?

The breakdown of glycogen to glucose, it is stimulated by glucagon.

What is the main site of insulin action?

The cell membrane is the principal site of insulin action. It binds with specific receptor proteins in the membrane which activates a complex series of intracellular signaling pathways. Most cells do not take up much, or any glucose, unless insulin is secreted and activates these signaling mechanisms. However, the brain is always able to take up glucose (i.e. the central nervous system is not dependent upon insulin for glucose uptake). Insulin has a half-life of about 5 minutes in the circulatory system. About 80% of the secreted insulin is normally degraded in the liver and kidneys.

How do you explain physiological respiratory changes during exercise?

The changes seen in respiratory rate and depth during exercise are difficult to explain physiologically. This is because the chemical factors such as carbon dioxide, oxygen, and hydrogen ions in the blood do not change enough during severe exercise to produce the dramatic increases in respiration that occur. It has been postulated that the increases are due to two neurogenic factors: 1) the stimulatory impulses from the higher centers of the brain and 2) proprioceptive stimulatory reflexes originating from joint proprioceptors. Both of these factors would stimulate the respiratory center to increase respiration.

What are conditions that describe the appearance and odor of urine?

The color of urine is normally amber (yellow) with the intensity of the color (light to dark) varying with the amount of urine eliminated. The color is due to pigments, such as urochrome, urobilin, and hematoporyphyrin, which are normally present in urine. The presence of abnormal substances may alter the color drastically. For example, hemoglobin will give the urine a red to brown color. Freshly voided urine is transparent, but after a few hours, becomes slightly opaque due to the separation and settling of epithelial cells, leukocytes, and mucus. After standing in the air, urine becomes alkaline, due to the conversion of urea to ammonia, and cloudy, due to the precipitation of substances such as phosphates. Cloudiness in freshly voided urine may indicate the presence of pus, blood or bacteria from urinary tract infections. Other abnormal urine colors and their causes are: yellow-orange to brownish-green (bilirubin from obstructive jaundice); smoky red (unhemolyzed RBC's from urinary tract); dark wine color (hemolytic jaundice); brown-black (malaria); green (bacterial infection). The odor of urine varies with dietary intake. The excretion of waste products associated with metabolism of certain foodstuffs (e.g. cabbage, asparagus) or the excretion of drugs by the kidneys frequently causes urine to have a foul odor. Decomposition and evaporation cause urine to have an ammoniacal odor.

What is the BTPS correction factor?

The correction factor that is used to correct for the difference in volume between ambient and lung (body) conditions is referred to as the *Body Temperature, Pressure, Saturated (or BTPS)* correction factor. It not only corrects for differences in temperature between body (lungs) and ambient conditions, it also corrects for any differences in pressure and water vapor saturation between ambient and body conditions. Any time you are reporting a volume of air, and you want it to represent the amount of air moved by the lungs, it must be reported in BTPS conditions. Common variables that are reported in BTPS conditions include VE, VC, TV, MVV. The BTPS correction factor can be calculated as follows: (310/273+Ta)(Pa-PH2O/Pa-47)

How is food digested?

The digestion of food is a process involving many enzymes. Some digestive enzymes are secreted by the salivary glands, the stomach, and the exocrine portion of the pancreas. Luminal membranes and cytoplasm of the cells lining the small intestine are responsible for other enzymes. There are many secretions, other than enzymes, that are important for digestive processes. For example, *bile salts*, which are made in the liver (and can be stored in the gall bladder), facilitate digestion of fats by emulsifying them (making large fat droplets into smaller fat droplets), which increases the surface area on which the enzymes can act. The stomach secretes hydrochloric acid to aid the digestive action of enzymes by allowing them to function at or near their optimum pH level. A number of transport mechanisms (i.e. diffusion, facilitated diffusion, solvent drag, active transport, and endocytosis) are responsible for the movement of substances from the lumen of the gastrointestinal (GI) tract to the extracellular fluid and onto the blood and lymph.

What is the midpoint?

The first point defined is the resting expiratory level or *midpoint* of the lung. The midpoint is the lung volume at rest following a normal expiration.

What is gluconeogenesis?

The formation of glucose from non-carbohydrate derivatives (amino acids, glycerol), it is stimulated by glucagon.

What is glycogenesis?

The formation of glycogen from glucose, it is stimulated by insulin.

What is the anatomy of the nephron?

The functional unit of the kidney is the nephron. Each kidney contains more than one million nephrons. A nephron consists of a renal tubule and Bwoman's capsule and renal vessels. The renal corpuscle, which is located in the cortical region of the kidney, is made up of network of capillaries called the glomerulus surrounded by a double-layered cup of the renal tubule called the glomerular capsule or Bowman's capsule. An afferent arteriole carries blood into the glomerular capillary bed, while blood is carried away from the glomerulus by way of an efferent arteriole. It is in the renal corpuscle that filtration of blood by the nephron begins. Leading away from the glomerular capsule, the renal tubular can be divided into the following parts: proximal tubule, loop of Henle, and distal tubule. A number of nephrons will converge via their distal tubules to form a collecting duct. The collecting ducts open into a minor calyx. A portion of the distal convoluted tubule comes near the afferent arteriole. This contact forms the juxtaglomerular apparatus, which secretes an enzyme, *renin*, important in raising blood pressure.

How do the kidneys play a role in long-term control of blood pressure?

The kidneys play the major role in the *long term control of blood pressure*. They are also the most potent regulators of blood pressure; they are the only regulatory system that can change blood pressure exactly back to the desired set point. All other control systems are proportional systems; they move blood pressure back towards the desired value, but may not return it all the way to the desired level. Obviously, if blood pressure is chronically elevated (hypertension), the kidneys must be playing some role. For example, if a subject was injected with a vasoconstrictor for several days, it would increase resistance and transiently increase pressure. However, this increased pressure would increase GFR, and increase sodium excretion from the body (natriuresis). This reduces ECF volume, and ultimately brings blood pressure back towards normal. This *pressure natriuresis* is a compensatoy mechanism that brings blood pressure back towards normal within a day or two.

What are the components of carbohydrates?

The major components of large carbohydrates are simple, single sugars known as monosaccharides. The three principal monosaccharides are glucose, fructose, and galactose. Monosaccharides may be joined in pairs to form *disaccharides* (double sugars). Maltose (glucose + glucose), sucrose (glucose + fructose), and lactose (glucose + galactose) are examples of disaccharides. Monosaccharides and disaccharides can be linked in a variety of combinations to form larger, complex carbohydrate polymers. Before carbohydrates can be absorbed by the mucosa, they must be broken down into their component monosaccharides and disaccharides by the process of enzymatic digestion.

What is hypercapnea?

The presence of an abnormally large amount of carbon dioxide in the circulating blood.

Under what conditions are chlorides observed in urine?

The principal chloride in urine is *sodium chloride*. Fevers and various forms of nephritis tend to decrease the renal output of chloride.

What is gastrin?

The principal physiological action of *gastrin* is to stimulate gastric acid and *pepsin* secretion in the stomach. It also stimulates growth of the gastric mucosa and gastric motility. The hormone is produced by G-cells located in the lateral walls of gastric mucosal glands in the antral portion of the stomach and the duodenal bulb. Gastrin secretion is affected by the contents of the stomach (i.e. increases in presence of products of protein digestion, particularly amino acids). It also increases with increased discharge of the vagus nerve (CN X). Blood-borne factors may also affect its secretion. Acid in the antrum of the stomach inhibits gastrin secretion (negative feedback mechanism).

What factors influence urine output and composition?

The quantity of urine formed and its quality (chemical composition) will vary depending upon such factors as exercise, dehydration, dietary intake, prergnancy, or pathological conditions. We are well aware of the effects of alcohol and caffeine on urine output. A substance that increases the rate of urine output is called a *diuretic*. There are a number of diuretic agents including ethanol. Ethanol inhibits vasopressin secretion, which decreases water reabsorption and thus increases urine output.

How is respiration regulated?

The rate and strength of respiratory muscle contraction, and therefore the rate and depth of respiration, are controlled by *medullary respiratory centers* (dorsal and ventral respiratory groups) located in the medulla oblongata at the base of the brainstem.

What affects the rate of enzymatic digestion?

The rate of enzymatic digestion of ingested food is dependent on the amount of enzyme present in relation to the amount of substrate (food to be digested), the temperature, and the activity of hydrogen ions (pH) in the medium in which the enzyme is acting. Digestion normally occurs within the lumen of the alimentary canal, where the temperature is relatively constant at 37 degrees Celsius. The pH varies considerably along the alimentary canal. All enzymes are affected by changes in pH. Each enzyme functions best within certain pH ranges called the optimum pH.

What is the renin-angiotensin-aldosterone system?

The secretion of aldosterone, and its resultant increase in sodium reabsorption is initiated by several stimuli including a *decrease in renal arterial blood pressure*. This results in the release of the hormone *renin* from the juxtaglomerular apparatus. Renin causes the conversion of a plasma protein produced in the liver, *angiotensinogen*, into *angiotensin I*. Angiotensin I is converted to *angiotensin II* by *angiotensin converting enzyme* in the lungs. Angiotensin II is one of the most potent natural vasoconstrictors in the humany body and is also a stimulator of aldosterone secretion by the zona glomerulosa cells of the adrenal cortex. Aldosterone causes an increase in the reabsorption of sodium by the distal tubules and collecting tubules of the kidneys. Because the urine has a relatively high sodium concentration compared to the blood, sodium reabsorption requires energy (i.e. it is reabsorbed by active transport). These mechanisms function to homeostatically maintain the proper *osmolarity* and *volume of fluids* (ECF volume, including blood volume) within the body and also play a major role in the long term regulation of *blood pressure*. The renin-angiotensin-aldosterone system is one of our most important hormonal systems in both the short, and long, term regulation of blood pressure.

What are the functional digestive features of the small intestine?

The small intestine has mucosal cells which possess a *brush border* consisting of numerous *microvilli*. This brush border has many enzymes and its luminal side possesses a layer of neutral and amino sugars known as the *glycocalyx*. Next to the brush border and the glycocalyx is a thin (100-400 micrometers) *unstirred water layer* (UWL) through which solutes must diffuse to reach the mucosal cells.

How does one estimate the amount of urinary solids?

The specific gravity can be utilized to approximate the urinary solids in grams per liter. This is achieved by multiplying the last two digits of the specific gravity by 2.66 (*Long's coefficient*). Example: if the specific gravity of the urine sample is 1.030, multiply 30 by 2.66 (30 x 2.66 = 79.8). So, 79.8 grams per liter is the approximate amount of urinary solids.

What is the function of the kidneys?

The two kidneys help eliminate waste and control water, acid-base, and electrolyte balance in the body. They also help regulate blood pressure, produce a factor that stimulates red blood cell formation, and serve as an intermediate step in the activation of vitamin D.

What is the expiratory reserve volume?

The volume of air that can be expired beyond the resting expiratory level is known as the *expiratory reserve volume*.

What are the pneumotaxic and apneustic centers?

There are also *pneumotaxic and apneustic centers* located anterior to the medulla in the pons,

What are the three major renal processes?

There are three major renal processes, *glomerular filtration*, *tubular secretion*, and *tubular reabsorption*, each subject to regulation, that ultimately determine the composition of urine and thus also determine our internal fluid composition. .

What is the cold pressor test?

Thermoreceptors and nociceptors -> SNS -> increase in MAP (vasoconstriction) -Normotensive should move back towards normal within 2 minutes First phase: activation of SNS due to pain, increased heart rate

What is the diving bradycardia reflex?

This response is believed to be due to face immersion and/or breath holding. This reflex has been observed in all vertebrates that have so far been tested for this response. The general response is a slowing of the heart rate with blood pressure remaining relatively constant or increase. This response is believed to be protective in nature. That is, since the body does not know when it will get its next breath of fresh air, the body tries to decrease blood flow to all organs except the heart and brain (which are both almost exclusively aerobic). This decrease in blood flow and oxygen uptake by all of our other organs means that oxygen supply to our most important organs (heart and brain) can be maintained longer, and the organism can survive longer under water.

What was the maltose test?

To test for maltose, we added 2 mL of *Benedict's solution* to each tube and placed it in a boiling water bath for 2 minutes. The color red indicated the presence of maltose, while blue indicated no maltose.

What was the starch test?

To test for starch, we added 1-2 drops of *Lugol's solution* to each tube. A dark purple color indicated the presence of starch, while shades of reddish brown indicated lesser amounts of starch.

What are the accessory organs?

Tongue Teeth Muscles of mastication and swallowing Salivary glands -Parotid glands -Submaxillary glands -Sublingual glands Pancreas Liver and gallbladder

What is the difference between Type I and Type II diabetes?

Type I diabetes mellitus is often called *juvenile-onset diabetes mellitus* because it has a higher prevalence in children than does Type II diabetes mellitus. Type II diabetes mellitus is often called *maturity-onset diabetes mellitus* because it tends to occur as an adult. Type II diabetes mellitus accounts for approximately 80-90% of all cases of diabetes mellitus, with the remaining 10-20% being Type I. Type I diabetics are permanently dependent on regular insulin injections for blood glucose regulation, and thus survival, hence the name insulin-dependent diabetes mellitus (often abbreviated IDDM). On the other hand, in Type II diabetes, insulin secretion is usually normal, and it may even be higher than in normal individuals. For this reason type II diabetics are not dependent on exogenous insulin, thus the name non-insulin-dependent diabetes melltius (often abbreviated NIDDM).

What is urine?

Urine is an ultrafiltrate of blood. Essentially everything that is present in urine has first been present in blood. About 1.2 liters of blood is delivered to the kidneys every minute in an average-sized person. Of the 1.2 liters, about 125 mL is filtered into the glomeruli, but only 1-2 mL actually appear as urine. Most (over 99%) of the fluid is reabsorbed from the kidney back into the blood, largely through the proximal tubule.

What are the fluid compartments in the body?

Water constitutes approximately 60% of body weight in an average subject (slightly higher in men and slightly lower in women). Thus, a 70 kg individual would have approximately 42 Liters of water (one kg of water = 1 L of water). The *intracellular fluid (ICF)* volume constitutes approximately 67% of the whole body fluid volume and the *extracellular fluid (ECF)* volume constitutes 33%. The ECF can be further divided into the *plasma volume*, which is approximately 20% of the ECF, and the *interstitial fluid volume*, which is approximately 80% of the ECF.

Under what conditions are hemoglobin and myoglobin observed in urine?

When the plasma level of *free hemoglobin* (not in erythrocytes) is greater than 100 mg/dL, hemoglobin is found in the urine (*hemoglobinuria*). This occurs when all the plasma protein-binding capacity for free hemoglobin is exhausted due to an excessive rate of destruction of red blood cells (i.e. too rapid for adequate storage or metabolism of hemoglobin). Causes for hemoglobinuria include: *hemolysis, burns, crushing injuries, transfusion reactions and toxins* such as snake venoms and those of poison mushrooms. Hemoglobin is also frequently observed in the urine during *menstruation*. A red, iron-containing, oxygen-carrying pigment found in skeletal muscle is myoglobin. Under abnormal conditions free myoglobin may appear in the urine. Causes for *myoglobinuria* include: *trauma* and *ischemia* (e.g. *acute myocardial infarction, muscle trauma, burns*), *metabolic disoders* (e.g. alcohol myopathy, potassium depletion, hypothermia), *severe muscle exertion* (e.g. convulsions, severe exercise, heat cramps), *muscle disease/inflammation* (e.g. muscular dystrophies), *infections/fever* (e.g. viral influenza, tetanus, gas gangrene), and *toxicity* (e.g. carbon monoxide).

What is the total lung capacity?

When the vital capacity and the residual volume are added together, one obtains the *total lung capacity*. TLC = VC + RV

What are ATPS conditions?

When we expel air from our lungs, that air rapidly cools from body temperature (~37 degrees Celsius) to the ambient temperature (between 20 and 24 degrees Celsius). Thus, the air that is moved from the lungs into the spirometer will occupy a smaller volume of space because it is cooler. When gas samples have been collected, but have not been corrected for such differences in temperature or pressure, we usually refer to this volume of gas as the volume under *ambient pressure, and temperature, saturated (or ATPS)* conditions. When performing spirometry, the volumes that are recorded directly from the spirometer represent the volume of air moved into the spirometer (volume of air under ATPS conditions), not the volume of air moved by the lungs. Thus, we will need to somehow correct for this difference in volume if we want to know the actual volume of air that was moved by the lungs.

How does oxygen affect respiratory centers?

While carbon dioxide and hydrogen ions affect respiration mainly by excitatory effects on the respiratory center itself, oxygen does not have a significant direct effect on the respiratory center of the brain in controlling respiration under normal conditions. Instead, oxygen acts almost entirely on the peripheral chemoreceptors located in the aortic and carotid bodies. These in turn transmit the appropriate impulses to the respiratory center for control of respiration. These receptors will only be stimulated a partial pressure of oxygen below 60 mmHg (normal arterial partial pressure of oxygen is 100mmHg). This mechanism does become important at altitudes greater than 8000 feet.

What is autoregulation?

controlled largely by local factors resulting from tissue metabolism. Local factors such as the concentrations of hydrogen ions, oxygen, carbon dioxide, ions, electrolytes, temperature, histamine, and various other metabolites are major controllers of blood flow in local tissues. When the tissues are active, by-products of metabolism (low pO2, high pCO2, low pH, high ADP concentrations, increased temperature) cause the sphincters to dilate, allowing blood to enter the capillaries. When the tissues are inactive, these factors are not present, and the sphincters constrict and shut off blood flow. This phenomenon of the tissues controlling their local blood flow is called *autoregulation*. It functions independent of sympathetic nerve stimulation and can override sympathetic input.

How do you convert between mg% and mM?

mM = mg%/18