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RENAL PHYSIOLOGY: PRACTICE QUESTIONSRenal Mechanisms

1. The term "renal autoregulation" refers in part to the fact that

A. the kidney does not require blood flow to sustain its active transportB. the kidney contains baroreceptors (pressure receptors) that contribute to the regulation of cardiac outputC. renal blood flow is relatively constant over a wide range of systemic arterial pressuresD. renal blood flow is not affected by activation of the sympathetic nerves that innervate the kidneyE. a combination of both C and D above

2. The nerves that innervate the kidney are essential for regulating which of the following?

A. Na-K-ATPase active transport pump rateB. renal autoregulation of blood flowC. urine volume and tonicity (osmolality)D. all of the aboveE. none of the above

3. Which of the following would be expected to cause renal inulin (or creatinine) clearance to increase?

A. dilation of the afferent arterioleB. dilation of the efferent arterioleC. constriction of the afferent arterioleD. constriction of the efferent arterioleE. both A and D above

4. 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 filtrateB. reabsorption of albumin from the proximal tubule is inhibited

C. secretion of albumin into the distal tubule and collecting ducts is increasedD. increased peritubular blood flow makes more albumin available for diffusion into the tubuleE. reduced active transport of sodium ion reduces cotransport of other substances, including albumin

5. As blood passes along the glomerular capillaries from the afferent to efferent arteriole, the net filtration pressure (P - )

A. increasesB. decreasesC. first decreases, reaches a minimum about half way along the capillary, then increasesD. first increases, reaches a maximum about half way along the capillary, then decreasesE. remains constant

6. Sodium is actively reabsorbed from the renal tubule in which of the following nephron segments?

A. proximal tubuleB. distal tubuleC. thick ascending limb of the loop of HenleD. all of the aboveE. none of the above

7. The rate of water reabsorption from the proximal tubule is determined primarily by the

A. rate of dissolved particle (solute) reabsorption from the proximal tubuleB. concentration of ADH (antidiuretic hormone) in the bloodC. osmotic pressure developed by plasma proteins in the proximal tubuleD. active transport of water molecules by the proximal tubule cellsE. passive filtration due to the high hydrostatic pressure in the proximal tubule

8. Urea has a higher concentration in the fluid that leaves the proximal tubule (and enters the loop of Henle) than in blood plasma because

A. urea is synthesized by proximal tubule cellsB. urea is secreted into the proximal tubuleC. urea is reabsorbed from the proximal tubule but at a lesser rate that water is reabsorbedD. urea diffuses back into the proximal tubule because of the high urea concentration in the renal medullaE. urea is actively transported into Bowman's capsule from the glomerular capillaries

9. In the proximal tubule, penicillin is

A. actively secreted into the tubuleB. actively reabsorbed from the tubuleC. passively reabsorbed from the tubuleD. metabolized by the tubule cellsE. neither secreted nor reabsorbed nor metabolized

10. At which sites would the concentration of creatinine be expected to be highest? (Note: assume the person is normally hydrated.)

A. glomerular filtrateB. end of the proximal tubuleC. end of the loop of HenleD. urineE. the concentration would be the same in all of the above, since creatinine is neither secreted or reabsorbed

11. 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 concentrationB. renal urea excretionC. renal urea clearance

D. urine urea concentrationE. all of the above

12. The following values are measured for potassium ion in a human subject.

Plasma K+ 5 meq/literUrine K+ 50 meq/literRenal creatinine clearance 80 ml/minUrine formation rate 1.5 ml/minute

This patient's potassium clearance is closest to which of the following?

A. 5 ml/minuteB. 7.5 ml/minuteC. 15 ml/minuteD. 50 ml/minuteE. 75 ml/minute

13. Assuming the subject in the preceding question is a normal adult, we can conclude that most likely potassium is

A. filtered but not secreted or reabsorbedB. secreted but not filtered or reabsorbedC. reabsorbed but not secreted or filteredD. filtered and secretedE. filtered and reabsorbed

ANSWER KEY TO RENAL MECHANISMS PRACTICE QUESTIONS

1. 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.).

2. E. Although the sympathetic nerves that innervate the kidney influence several aspects of kidney physiology, they are not essential for normal renal function.

3. 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.

4. 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.

5. 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.

6. 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.

7. A. The proximal tubule is very permeable to water, so water reabsorption follows solute (dissolved particle) reabsorption.

8. C.

9. A.

10. 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.

11. 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.

12. C. Remembering that CK = UK x V / PK, so CK = 50 x 1.5 / 5 = 15 ml/min.

13. E. Since CK is less than GFR (80 ml/min, as measured by creatinine clearance in question 12), potassium must be filtered and reabsorbed.

1. Stimulation of the osmoreceptors in the hypothalamus would be expected to cause all of the following to increase except

A. ADH release from the pituitaryB. water reabsorption from the renal collecting ductC. rate of urine formationD. osmolality of urineE. none of the above; that is, none are exceptions since all would be expected to increase

2. 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 HenleC. fluid leaving the descending thin limb and entering the ascending thin limb of the loop of HenleD. fluid leaving the thick ascending segment of the loop of Henle and entering the distal tubuleE. fluid leaving the collecting ducts (urine)

3. 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 urineB. small volume of concentrated urineC. large volume of dilute urineD. small volume of dilute urineE. normal volume of urine of normal osmolality

4. Drinking which of the following would lead to the highest rate of ADH secretion and release?

A. two liters of distilled waterB. two liters of sea water (mainly hyperosmotic saline)C. two liters of iso-osmotic (isotonic) salineD. two liters of human blood plasmaE. none of the above, since drinking two liters of any liquid leads to inhibition of ADH release

ANSWER KEY TO RENAL WATER REGULATION PRACTICE QUESTIONS

1. 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.

2. D

3. C Ethanol inhibits release of ADH from the posterior pituitary, so a large volume of dilute urine would be excreted.

4. 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.

1. In a patient with severe renal artery stenosis (narrowing), all of the following would be expected to be increased above normalexcept

A. plasma renin concentrationB. plasma angiotensin II concentrationC. blood pressure (hydrostatic pressure) in the glomerular capillaries

D. resistance to blood flow in the efferent arterioleE. systemic arterial blood pressure

2. 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 reabsorptionB. increasing renal resistance to blood flowC. causing plasma proteins to be excreted in the urineD. causing systemic arterial hypertensionE. reducing glomerular filtration rate

3. Which of the following is the stimulus for increased secretion of atrial natriuretic peptide (ANP)?

A. increase blood plasma osmolality above normalB. decrease blood plasma osmolality below normalC. increase systemic arterial pressureD. increase venous blood volume and atrial pressureE. increase cardiac contractility (force of contraction)

4. 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+ excretionB. increase in Na+ excretion and decrease K+ excretionC. decrease in Na+ excretion and increase K+ excretionD. decrease in Na+ excretion and decrease K+ excretionE. decrease in Na+ excretion but no effect on K+ excretion

. 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.

2. E. The ACE inhibitor will reduce angiotensin II concentration, so arterial blood pressure will drop, which reduce glomerular capillary hydrostatic pressure and filtration.

3. D.

4. 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).

1. In which of the following fluids is the pH highest (most alkaline)? (Assume the person is normal.)

A. systemic arterial blood plasmaB. systemic venous blood plasmaC. urineD. all of the above, since pH is normally of the same for allE. A and B above, since blood plasma pH is relatively uniform

2. The ammonium (NH4+) ion that may be present in urine is produced by

A. breakdown of urea in the liverB. metabolism of amino acid in the renal tubule and collecting ductC. aerobic carbohydrate metabolismD. gylcolytic pathways during anaerobic metabolismE. gluconeogensis during starvation

3. 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 ventilationB. high PaCO2 stimulates respiratory ventilationC. low PaCO2 inhibits respiratory ventilationD. low PaCO2 stimulates respiratory ventilation

E. none of the above, since respiratory compensation for metabolic alkalosis can be complete

4. The appearance of large amounts of ammonium ion (NH4+) in the urine is characteristic of the renal response to

A. respiratory acidosisB. respiratory alkalosisC. acidosis resulting from pancreatic diabetesD. alkalosis resulting from gastric vomitingE. both A and C above

5. 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. hyperventilationB. increase in the acid form of the blood fixed buffersC. decrease in blood bicarbonate ion concentrationD. increase in urine bicarbonate ion excretionE. increase in urine ammonium ion excretion

6. A systemic arterial blood sample taken from the above individual an hour after his HCl "adventure" might show which of the following?

A. HCO3- = 34 meq/liter; PaCO2 = 50 mmHg

B. HCO3- = 34 meq/liter; PaCO2 = 30 mmHg

C. HCO3- = 14 meq/liter; PaCO2 = 50 mmHg

D. HCO3- = 14 meq/liter; PaCO2 = 30 mmHg

E. HCO3- = 24 meq/liter; PaCO2 = 40 mmHg

7. 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 6.90HCO3

- 13 meq/literPaCO2 68 mmHg

This patient's acid-base status is most accurately described as

A. uncompensated metabolic acidosisB. uncompensated respiratory acidosisC. simultaneous respiratory and metabolic acidosisD. respiratory acidosis with partial renal compensationE. respiratory acidosis with complete renal compensation

1. A. Systemic arterial blood has a higher (more alkaline) pH than systemic venous blood because of the CO2 added by metabolizing cells as blood passes through the systemic vascular beds. Urine is generally more acid than plasma because of the necessity of excreting the excess fixed (non-volatile) acids created by metabolism.

2. B.

3. 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).

4. 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

+.

5. D. Renal compensation for acidosis involves bicarbonate reabsorption, not bicarbonate excretion.

6. D. After an hour, we should expect respiratory compensation but not renal compensation. Thus, there will be a low bicarbonate due mainly to the acid injection and low PaCO2 due to the hyperventilation.

7. 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.

Question 1Back to Top

Question: Loop of Henle is concerned with:

1. excretory system

2. reproductive system

3. nervous system

4. muscular system

Answer: 1


Question: Urea is transported by

1. plasma

2. blood

3. RBC

4. WBC

Answer: 1


Question: The kidneys resemble the contractile vacuoles of amoeba in

1. expelling out excess of water

2. expelling out glucose

3. expelling out urea and uric acid

4. expelling out salts

Answer: 1


Question: Glucose is reabsorbed in the kidney mainly by

1. Bowman's capsule

2. Loop of Henle

3. Proximal Convoluted Tubule

4. Distal Convoluted Tubule

Answer: 3


Question: Excess amino acids in the body are broken down to form urea in

1. kidney

2. liver

3. spleen

4. pancreas

Answer: 2


Question: Difference between glomerular filtrate and blood plasma is of

1. proteins in plasma

2. potassium

3. first is white and second is yellow

4. proteins in glomerular filtrate

Answer: 1

Question 7

Back to Top

Question: In the kidneys of mammals, Loop of Henle can be found in

1. medulla

2. cortex

3. pelvis

4. pyramid

Answer: 1


Question: In the kidney the correct sequence of formation of urine involves the following processes:

1. glomerular filtration, reabsorption, tubular secretion

2. reabsorption, filtration, secretion

3. filtration, secretion, reabsorption

4. reabsorption, secretion, filtration

Answer: 1


Question: A severe fall in blood pressure disturbs the function of kidneys and reduces

1.

renal filtration

2.

glomerular filtration

3.

reabsorption

4.

secretion of nitrogenous wastes

Answer: 2


Question: Excretion of bile pigments in urine indicates

1. anaemia

2. diabetes

3. gout

4. jaundice

Answer: 4


Question: Workers in deep mines usually suffer from dehydration because

1.

water is lost due to evaporation

2.

water is lost due to defecation

3.

water is lost in the form of sweat

4.

water is lost along with salts in the form of sweat

Answer: 4


Question: The concentration of urea is highest in

1.

renal vein

2.

hepatic portal vein

3 dorsal aorta

.

4.

hepatic vein

Answer: 4


Question: The concentration of urea is least in

1.

renal artery

2.

renal vein

3.

post canal

4.

dorsal aorta

Answer: 2


Question: The function of the mammalian kidney is to excrete

1. extra salts, urea and excess water

2. extra urea, excess water and excess amino acids

3. extra urea, extra carbohydrates and extra water

4. extra urea, extra salts and extra sugar

Answer: 1


Question: The plasma is similar in its composition with the filtrate produced in glomerulus except for the presence of

1.

glucose

2.

chlorides

3.

proteins

4.

amino acids

Answer: 3


Question: If a man takes in large amount of proteins he is likely to secrete more amount of

1.

urea

2.

uric acid

3.

sugar

4.

carbon dioxide

Answer: 1


Question: What will happen if one kidney of a person is removed

1. he will survive and remain normal

2. he will die

3. urea will go on accumulating in the blood

4. urination will stop

Answer: 1


Question: The glomerular filtrate contains

1. blood minus cells

2. blood minus cells and minus proteins

3. blood minus proteins

4. plasma minus cells minus proteins

Answer: 2


Question: In the distal convoluted tubule of the nephrons

1. Sodium reabsorption requires energy

2. Secretion of potassium does not require energy

3. Water reabsorption requires energy

4. Ammonia is secreted

Answer: 1


Question: The mechanism of uric acid secretion in the nephron is

1. diffusion

2. excretion

3. ultrafiltration

4. osmosis

Answer: 3


Question: Human kidney has

1.

Ciliated nephrons

2.

No loop of Henle

3.

Meronephric duct

4.

Glomeruli concentrated in cortex

Answer: 4


Question: Uriniferous tubules are found in

1.

Kidneys

2.

Testes

3.

Ovary

4.

Stomach

Answer: 1


Question: Reabsorption of chloride ions from the glomerular filtrate in the kidney tubule is carried out by

1. Osmosis

2. Diffusion

3. Active transport

4. Brownian movement

Answer: 2


Question: Bowman's capsule and glomerulus form

1. cortex

2. pyramid

3. malphigian body

4. medulla

Answer: 3

Correct__________ failure is caused by obstruction of urine flow. (urethral obstruction by enlarged prostate or tumor; ureteral or kidney pelvis obstruction by calculi)A.prerenalB.intrarenalC.postrenalD.perirenal

CorrectAgents that damage the kidney tissue are called:A.nephronsB.nephrotoxinsC.antibodiesD.enterotoxins

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