Renal System - Physiology Question PDF

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1.

The reason that respiratory compensation for metabolic alkalosis can never be complete (return plasma pH to normal) is that (Note: PaCO2 = systemic arterial carbon dioxide partial pressure.) A. high PaCO2 inhibits respiratory ventilation B. high PaCO2 stimulates respiratory ventilation C. low PaCO2 inhibits respiratory ventilation D. low PaCO2 stimulates respiratory ventilation E. none of the above, since respiratory compensation for metabolic alkalosis can be complete B. Respiratory compensation for metabolic alkalosis involves depression of alveolar ventilation to accumulate CO2. However, the higher PaCO2 stimulates ventilation, which prevents complete compensation (return of pH to 7.4). 2.

The appearance of large amounts of ammonium ion (NH4+) in the urine is characteristic of the renal response to A. respiratory acidosis B. respiratory alkalosis C. acidosis resulting from pancreatic diabetes D. alkalosis resulting from gastric vomiting E. both A and C above E. Renal compensation for acidosis, of both respiratory and metabolic origin (assuming the metabolic acidosis is not due to renal pathology), involves synthesis of NH3 and subsequent excretion of NH4+.

3.

An individual hoping for an LSD "acid high" mistakenly gives himself an intravenous injection of hydrochloric acid. The responses of his body which attempt to compensate for this ignorance of physiology include all of the following except A. hyperventilation B. increase in the acid form of the blood fixed buffers C. decrease in blood bicarbonate ion concentration D. increase in urine bicarbonate ion excretion E. increase in urine ammonium ion excretion D. Renal compensation for acidosis involves bicarbonate reabsorption, not bicarbonate excretion. 4.

A young woman is found comatose, having taken an unknown number of sleeping pills an unknown time before. An arterial blood sample yields the following values: pH 6.90 HCO3- 13 meq/liter PaCO2 68 mmHg This patient's acid-base status is most accurately described as A. uncompensated metabolic acidosis B. uncompensated respiratory acidosis C. simultaneous respiratory and metabolic acidosis D. respiratory acidosis with partial renal compensation E. respiratory acidosis with complete renal compensation C. The low pH indicates acidosis. The low bicarbonate indicates metabolic acidosis. The high PaCO2 indicates respiratory acidosis. Presumably, the narcotic overdose depressed the patient's respiratory center in the brain, reducing ventilation. The reduction of available oxygen then caused cellular anaerobic metabolism to increase, leading to production of lactic acid, etc. 5.

In a patient with severe renal artery stenosis (narrowing), all of the following would be expected to be increased above normal except A. plasma renin concentration B. plasma angiotensin II concentration C. blood pressure (hydrostatic pressure) in the glomerular capillaries D. resistance to blood flow in the efferent arteriole E. systemic arterial blood pressure C. Blood flowing through the stenosis will encounter a high resistance, which will cause the pressure to drop on the downstream side of the stenotic area. This will lead to secretion of renin, which causes blood angiotensin II to increase, which will raise systemic arterial blood pressure and constrict the renal efferent arteriole. However, blood pressure in the glomerular capillaries will fall because of the drop in pressure as blood enters the glomerular vessels.

6.

Administration of an Angiotensin Converting Enzyme inhibitor (ACE inhibitor) to the above patient might lead to acute renal failure by A. inhibiting renal tubule potassium reabsorption B. increasing renal resistance to blood flow C. causing plasma proteins to be excreted in the urine D. causing systemic arterial hypertension E. reducing glomerular filtration rate E. The ACE inhibitor will reduce angiotensin II concentration, so arterial blood pressure will drop, which reduce glomerular capillary hydrostatic pressure and filtration. 7.

Which of the following is the stimulus for increased secretion of atrial natriuretic peptide (ANP)? A. increase blood plasma osmolality above normal B. decrease blood plasma osmolality below normal C. increase systemic arterial pressure D. increase venous blood volume and atrial pressure E. increase cardiac contractility (force of contraction)

8.

An increase secretion of renin would be expected to have what effect on sodium excretion and potassium excretion in urine? A. increase in Na+ excretion and increase K+ excretion B. increase in Na+ excretion and decrease K+ excretion C. decrease in Na+ excretion and increase K+ excretion D. decrease in Na+ excretion and decrease K+ excretion E. decrease in Na+ excretion but no effect on K+ excretion C. Increase renin will eventually result in a rise in aldosterone, which increases Na-K pumping (antiport) in the renal distal tubule and collecting duct. Thus, Na reabsorption will increase (reduce excretion) and K secretion will increase (increase excretion). 9.

Stimulation of the osmoreceptors in the hypothalamus would be expected to cause all of the following to increase except A. ADH release from the pituitary B. water reabsorption from the renal collecting duct C. rate of urine formation D. osmolality of urine E. none of the above; that is, none are exceptions since all would be expected to increase C. The increased ADH release would lead to increased water reabsorption from the later distal tubule and collecting ducts, so urine formation rate would decrease. 10. As fluid passes along a juxtamedullary nephron, where is its osmolality (total concentration of dissolved particles) lowest? (Note: assume a normal concentration of circulating ADH.) A. Bowman's capsule (glomerular filtrate) B. fluid leaving the proximal tubule and entering the loop of Henle C. fluid leaving the descending thin limb and entering the ascending thin limb of the loop of Henle D. fluid leaving the thick ascending segment of the loop of Henle and entering the distal tubule E. fluid leaving the collecting ducts (urine)  11. Drinking vodka (a beverage with a high ethanol content, for those of you unfamiliar with this substance) would be expected to cause excretion of a A. large volume of concentrated urine B. small volume of concentrated urine C. large volume of dilute urine D. small volume of dilute urine E. normal volume of urine of normal osmolality C Ethanol inhibits release of ADH from the posterior pituitary, so a large volume of dilute urine would be excreted.

12. Drinking which of the following would lead to the highest rate of ADH secretion and release? A. two liters of distilled water B. two liters of sea water (mainly hyperosmotic saline) C. two liters of iso-osmotic (isotonic) saline D. two liters of human blood plasma E. none of the above, since drinking two liters of any liquid leads to inhibition of ADH release B Drinking two liters of sea water would increase extracellular osmolality, thus stimulating hypothalamic osmoreceptors and leading to a greater increase of ADH release than drinking two liters of the other solutions indicated. 13. The term "renal autoregulation" refers in part to the fact that A. the kidney does not require blood flow to sustain its active transport B. the kidney contains baroreceptors (pressure receptors) that contribute to the regulation of cardiac output C. renal blood flow is relatively constant over a wide range of systemic arterial pressures D. renal blood flow is not affected by activation of the sympathetic nerves that innervate the kidney E. a combination of both C and D above C Autoregulation refers to the relatively constant rate of both RBF and GFR over a wide range of systemic arterial pressures (but it does not imply that RBF and GFR are always constant, since they can be influenced by sympathetic stimulation, hormones, etc.). 14. The nerves that innervate the kidney are essential for regulating which of the following? A. Na-K-ATPase active transport pump rate B. renal autoregulation of blood flow C. urine volume and tonicity (osmolality) D. all of the above E. none of the above E. Although the sympathetic nerves that innervate the kidney influence several aspects of kidney physiology, they are not essential for normal renal function. 15. Which of the following would be expected to cause renal inulin (or creatinine) clearance to increase? A. dilation of the afferent arteriole B. dilation of the efferent arteriole C. constriction of the afferent arteriole D. constriction of the efferent arteriole E. both A and D above E. Both dilation of the afferent arteriole and constriction of the efferent arteriole would increase glomerular capillary hydrostatic pressure and thus increase GFR. Note that inulin (or creatinine) clearance is a measure of GFR. 16. Kidney inflammation may result in the appearance of albumin (a plasma protein) in the urine because A. more albumin enters the proximal tubule in the glomerular filtrate B. reabsorption of albumin from the proximal tubule is inhibited C. secretion of albumin into the distal tubule and collecting ducts is increased D. increased peritubular blood flow makes more albumin available for diffusion into the tubule E. reduced active transport of sodium ion reduces cotransport of other substances, including albumin A. Loss of the glomerular filtration barrier negative charge, characteristic of nephritis, leads to increased filtration of negatively-charged plasma proteins. If the protein filtered load exceeds the limited capacity of the renal tubules to reabsorb protein (Tm-Protein), the urine will contain plasma proteins. 17. As blood passes along the glomerular capillaries from the afferent to efferent arteriole, the net filtration pressure A. increases B. decreases C. first decreases, reaches a minimum about half way along the capillary, then increases D. first increases, reaches a maximum about half way along the capillary, then decreases E. remains constant B. Hydrostatic pressure decreases because of capillary resistance. Osmotic pressure increases because plasma protein concentration increases as fluid is lost by filtration. So net filtration pressure decreases as blood passes along the glomerular capillary, and may even reach zero (no net filtration force) by the end of the capillary.

18. Sodium is actively reabsorbed from the renal tubule in which of the following nephron segments? A. proximal tubule B. distal tubule C. thick ascending limb of the loop of Henle D. all of the above E. none of the above D. Sodium is reabsorbed by active transport in all of the segments named, although it is not actively transported in either the descending or ascending thin limbs of the loop of Henle. 19.Ther at eofwat err eabs or pt i onf r om t hepr ox i malt ubul ei sdet er mi nedpr i mar i l ybyt he A.r at eofdi s sol v edpar t i c l e( sol ut e)r eabsor pt i onf r om t hepr ox i malt ubul e B.c oncent r at i onofADH( ant i di ur et i chor mone)i nt hebl ood C.osmot i cpr ess ur edev el opedbypl asmapr ot ei nsi nt hepr oxi malt ubul e D.act i v et r ans por tofwat ermol ecul esbyt hepr oxi malt ubul ecel l s E.pass i v efil t r at i onduet ot hehi ghhydr ost at i cpr essur ei nt hepr oxi malt ubul e A.Thepr oxi malt ubul ei sver yper meabl et owat er ,sowat err eabsor pt i onf ol l owssol ut e( di ssol ved par t i cl e)r eabsor pt i on. 20. Ur eahasahi gherconcent r at i oni nt heflui dt hatl eav est hepr ox i malt ubul e( andent er st hel oopofHenl e) t hani nbl oodplasma because A. urea is synthesized by proximal tubule cells B. urea is secreted into the proximal tubule C. urea is reabsorbed from the proximal tubule but at a lesser rate that water is reabsorbed D. urea diffuses back into the proximal tubule because of the high urea concentration in the renal medulla E. urea is actively transported into Bowman's capsule from the glomerular capillaries 21. In the proximal tubule, penicillin is A. actively secreted into the tubule B. actively reabsorbed from the tubule C. passively reabsorbed from the tubule D. metabolized by the tubule cells E. neither secreted nor reabsorbed nor metabolized 22. At which sites would the concentration of creatinine be expected to be highest? (Note: assume the person is normally hydrated.) A. glomerular filtrate B. end of the proximal tubule C. end of the loop of Henle D. urine E. the concentration would be the same in all of the above, since creatinine is neither secreted or reabsorbed D. Remember that creatinine is filtered but neither reabsorbed nor secreted (approximately), so creatinine concentration depends on the amount of water remaining. The volume of urine is less that the volume of fluid at any of the other sites listed. 23. Suppose a person loses the function of half his nephrons because of renal degenerative disease. Assuming the person survives and reaches a new steady state and that body urea production remains normal, which of the following would be expected to decrease below normal? A. plasma urea concentration B. renal urea excretion C. renal urea clearance D. urine urea concentration E. all of the above C. Less urea would be cleared because less urea is be filtered. The reduced filtration would cause blood urea concentration to rise until the amount of urea excreted was equal to the amount of urea produced by protein metabolism even with the reduced plasma clearance. 24. For those substances that are actively reabsorbed, the maximal amount that can be transported per unit time by the kidney tubules: A. depends on the maximum rate at which the transport mechanism itself operates B. is directly related to the plasma concentration of the substance C. is termed the tubular transport maximum D. is dependent upon tubular load E. A and C are correct.

25. If the clearance of Substance X is greater than the clearance of inulin, it is most likely that Substance X is: A. bound to tubular proteins B. bound to plasma proteins C. secreted D. reabsorbed E. neither secreted nor reabsorbed 26. Co-transport of glucose: A. is equivalent to a uniport for glucose B. will not be affected if the Na+/K+ pump is blocked C. cannot move glucose against its concentration gradient D. is equivalent to an antiproton E. depends on the interaction of Na+ with the glucose carrier 27. The plasma concentration at which a particular substance begins to appear in the urine is the: A. transport maximum (Tm) B. fractional excretion C. filtered load D. renal threshold E. titration point  28. Renin is produced and secreted from granules located in the: A. macula densa B. mesangial cells C. intercalated cells D. afferent arteriole E. interstitial cells 29. About 4 to 6 days after you place a normal person on a low-sodium diet, which of the following will be observed? A. plasma renin and aldosterone are below normal B. plasma renin and aldosterone are above normal C. plasma sodium concentration is below normal D. plasma sodium concentration is normal E. B and D are correct 30. The normal human glomerular filtration rate (GFR) is approximately (in mL/min): A. 25 B. 50 C. 125 D. 300 E. 500 31. Which of the following statements is/are correct? A. Filtration fraction equals glomerular filtration rate divided by renal plasma flow. B. Tubular maximum secretion has a finite upper limit, though it exhibits a phenomenon analogous to the threshold phenomenon for reabsorption. C. Clearance ratio equals renal clearance of one substance divided by the clearance of another substance. D. Effective renal plasma flow is the volume of plasma flow supplied to juxtamedullary nephrons. E. A, B, and C are correct. 32. The renal "countercurrent" mechanism is dependent upon the anatomic relationship between: A. the distal tubule and the macula densa B. the loop of Henle and the macula densa C. the loop of Henle and the vasa recta D. the glomerulus and the afferent and efferent arterioles E. the glomerulus and the proximal tubule 33. If renal perfusion pressure does not change, which of the following changes in afferent and efferent arteriolar resistance would result in an increase in renal blood flow but no change in filtration fraction? Afferent arteriolar resistance Efferent arteriolar resistance A unchanged decreased B decreased unchanged C increased unchanged D decreased decreased E increased increased

34. An increase in the osmolality of the extracellular fluid will: A. stimulate the volume and osmoreceptors, and stimulate ADH secretion B. stimulate the volume and osmoreceptors, and inhibit ADH secretion C. inhibit the volume and osmoreceptors, and stimulate ADH secretion D. inhibit the volume and osmoreceptors, and inhibit ADH secretion E. cause no change in ADH secretion 35. Polyuria (diuresis) occurs in a diabetic patient who has a GFR = 120 mL/min and a blood sugar = 350 mg/dL. This is indicative of: A. losses of water and sodium which could be prevented by administration of antidiuretic hormone (ADH) and an aldosterone-like mineralocorticoid B. diuresis due to reduced active transport of sodium out of the tubule because of diminished activity of the Na+/K+ ATPase C. a cellular and extracellular over-hydration due to water retention, caused by the glucose D. an osmotic diuresis due to glucosuria, in which water loss will exceed "salt" loss E. B and D are correct. 36. The tonicity of the urine as it enters the renal collecting duct is: A. isotonic B. hypotonic or isotonic, but never hypertonic C. hypotonic D. hypertonic E. hypertonic or isotonic, but never hypotonic 37. Which of the following might you expect to find associated with chronic renal failure? A. elevated packed cell volume (hematocrit) B. abnormally low plasma creatinine concentration C. decreased bone density D. lower than normal PTH (parathyroid hormone) concentration E. None of the above is correct 38. The loops of Henle of the outer cortical nephrons: A. are functionally unimportant in the renal conservation of sodium and water B. do not contribute to the medullary osmotic gradient C. do not participate in the urinary diluting mechanism D. do not play any important role in overall renal function and are simply unimportant vestiges of evolutionary development E. A and C are correct. 39. Ammonia produced by the kidneys comes mainly from: A. glutamine B. glycine C. leucine D. alanine E. B and D are correct.  40. Glomerular filtration produces an ultrafiltrate of plasma: A. in which the concentration of electrolytes is equal to plasma B. in which the concentration of protein is equal to plasma C. containing only those substances which must be eliminated in the urine D. A and B are correct. E. B and C are correct. 41. Which of the following is NOT a function of the kidneys? A. regulation of extracellular volume B. regulation of plasma glucose concentration C. regulation of arterial blood pressure D. excretion of the end products of protein metabolism E. excretion of foreign chemicals (e.g. pharmaceuticals, food additives, etc.) 42. Which of the following does NOT contribute to titratable acid when found in the urine? A. H2PO4B. lactic acid C. beta-hydroxybutyric acid D. acetoacetic acid E. NH4+

43. Which of the following does NOT contribute to the formation of maximally concentrated urine? A. active NaCl transport in the proximal convoluted tubule B. active NaCl transport in the thick ascending limb of the loop of Henle C. impermeability of the thick ascending limb of the loop of Henle to water D. high water permeability of the collecting duct due to presence of ADH E. presence of urea in the inner medullary interstitium 44. Concerning the measurement of renal plasma flow (RPF) and glomerular filtration rate(GFR): A. inulin is a good GFR marker because it is freely filtered in the glomeruli and it is not reabsorbed, or secreted, by the renal tubules B. inulin concentration in the proximal tubule's lumen increases progressively as water is reabsorbed in the segment of the nephron C. PAH (para-amino-hippuric acid)is a good marker of renal plasma flow because it is freely filtered and is rapidly secreted by the proximal tubule; as a result very little PAH reaches the renal vein D. A and C are correct E. all are correct 45. Concerning the functional histology of the kidney: A. the superficia...