Practice Questions Flashcards
Which of the following is most likely to produce an increase in GFR in patients with acute renal failure?
A. administration of angiotensin II
B. contraction of glomerular mesangial cells
C. dilation of afferent arterioles
D. increased renin release from the JG apparatus
E. volume depletion
C. dilation of afferent arterioles
Substance X is injected into an arterial line to assess its renal handling. All of substance X appears in the urine and none is detected in the renal vein. What do these findings indicate about the renal handling of substance X?
a. it must be filtered by the kidney
b. it must be reabsorbed by the kidney
c. its clearance must be equal to GFR
d. its clearance is equal to RPF
e. its urinary concentration must be higher than its plasma concentration
d. its clearance is equal to RPF
Aldosterone secretion is increased when there is a decrease in which of the following?
a. ACTH
b. Angiotensin II
c. Potassium
d. Renin
e. Sodium
e. Sodium
Which of the following statements concerning normal renal handling of proteins is correct?
a. Proteins are more likely to be filtered if they are negatively charged
b. Proteins can be filtered and secreted but not reabsorbed by the kidney
c. Most of the proteins excreted each day is derived from tubular secretion
d. Protein excretion is directly related to plasma protein concentration
e. Protein excretion is increased by sympathetic stimulation of the kidney
e. Protein excretion is increased by sympathetic stimulation of the kidney
A 92 y/o male presents with dehydration following 4 days of persistent diarrhea. Under this circumstance, hypotonic fluid would be expected in which of the following?
a. Glomerular filtrate
b. Proximal tubule
c. Ascending limb of the loop of Henle
d. Cortical collecting tubule
e. Distal collecting duct
c. Ascending limb of loop of henle
Which of the following statements best describes the action or secretion of renin?
a. converts angiotensin I to angiotensin II
b. converts angiotensinogen to angiotensin I
c. it is secreted by cells of the proximal tubule
d. its secretion is stimulated by increased mean renal arterial pressure
e. its secretion leads to loss of sodium and water from plasma
b. it converts angiotensinogen to angiotensin I
The effect of decreasing the resistance of the afferent arteriole in the glomerulus of the kidney is to decrease which of the following aspects of renal function?
a. filtration fraction
b. GFR
c. oncotic pressure of peritubular capillary fluid
d. renal plasma flow
e. renin release from JG cells
e. renin release from JG cells
A 36 y/o man presents with low renin essential HTN. Renin release from the JG apparatus is normally inhibited by which of the following?
a. aldosterone
b. beta-adrenergic agonists
c. increased pressure within the afferent arterioles
d. prostaglandins
e. stimulation of the macula densa
c. increased pressure within the afferent arterioles
A 58 y/o male is hospitalized following an acute MI. Several days later, the patient’s 24 hour urine output is lower than normal. An increase in which of the following contributes to a reduced urine flow in a patient with CHF and reduced effective circulating volume?
a. ANP
b. Renal natriuretic peptide (urodilatin)
c. Renal perfusion pressure
d. Renal sympathetic nerve activity
e. Sodium delivery to the macula densa
d. Renal sympathetic nerve activity
[an increase in renal sympathetic nerve activity promotes a decrease in NaCl and water excretion by decreasing GFR, increasing renin secretion, and increasing tubular NaCl reabsorption]
A 58 y/o man presents with hematuria, abdominal pain and fatigue. Physical exam reveals a flank mass on the left kidney. Lab studies show anemia and increase creatinine and BUN suggestive of advanced disease. A decrease in GFR would result from which of the following?
a. Decrease in concentration of plasma protein
b. Increase in afferent arteriolar pressure
c. Increase in RBF
d. Compression of the renal capsule
e. Constriction of the efferent arteriole
d. Compression of the renal capsule
Renal and pulmonary biopsies in a 35 y/o woman with Wegner’s granulomatosis demonstrate glomerulonephritis and a granulomatous vasculitis in the lungs. In adults, which of the following is greater in the pulmonary circulation compared to the renal circulation?
a. Arterial pressure
b. Blood flow
c. Capillary hydrostatic pressure
d. Capillary oncotic pressure
e. Vascular resistance
b. Blood flow
A hypertensive patient develops chronic renal failure from progressive nephrosclerosis. Which of the following is associated with chronic renal failure?
a. A decrease in the excretion of creatinine
b. A decrease in the fractional excretion of sodium
c. A decrease in net acid excretion
d. An increase in free water clearance
e. A normal anion gap
a. A decrease in excretion of creatinine
ADH conserves water by
A. Constricting afferent arterioles, thereby reducing the GFR
B. Increasing water reabsorption by the PCT
C. Stimulating active reabsorption of solutes in the descending LOH
D. Increasing water permeability of the collecting duct
E. Blocking urea secretion in the LOH
D. Increasing water permeability of the collecting duct
Secretion of ADH by the posterior pituitary is decreased by
A. An increase in BP in the renal artery B. Increased pressures in the cardiac atria C. A decrease in BP in the carotid sinus D. An increase in plasma osmolality E. Dehydration
B. Increased pressures in the cardiac atria
Which statement is true about the renal cortex?
A. Contains 60% of the glomeruli
B. There is a gradient of osmolality that increases from the capsule toward the corticomedullary junction
C. The cortical interstitium contains virtually the same concentration of small solutes as does the peritubular capillary blood
D. There are no tubular segments in the cortex beyond the proximal convoluted tubule
E. The thick ascending limb of the LOH begins at the corticomedullary junction
C. The cortical intertitium contains virtually the same concentration of small solutes as does the peritubular capillary blood
A patient with a serum creatinine of 0.8 mg/dL submits a 12 hour urine collection containing 400 mg of creatinine. What is his creatinine clearance in mL/min?
A. 50 mL/min B. 69 mL/min C. 100 mL/min D. 145 mL/min E. 800 mL/min
B. 69 mL/min
How would RBF, GFR, glomerular capillary hydrostatic pressure, and peritubular capillary hydrostatic pressure change with a 50% decrease in renal efferent arteriolar resistance and no change in afferent arteriolar resistance or arterial pressure?
RBF increase
GFR decrease
Glom. cap hydrostatic pressure decrease
Peritubular cap hydrostatic pressure increase
A medical student caring for a hypertensive patient worries that elevated arterial pressure may have caused kidney damage d/t increased renal blood flow, however the patient’s creatinine is within the normal range. Which of the following mechanisms of renal blood flow autoregulation prevented hypertensive nephropathy in this patient?
A. Increased JG cell stimulation B. Increased secretion of prostaglandins C. Contraction of afferent arterioles D. Decreased solute delivery to the macula densa E. Increased secretion of renin
C. Contraction of afferent arterioles
What effect does decreased plasma protein concentration have on glomerular dynamics?
A. Decreased GFR B. Decreased RPF C. Decreased FF D. Increased RPF E. Increased GFR
E. Increased GFR
In normal kidneys, which of the following is true of the osmolarity of renal tubular fluid that flows through the early distal tubule in the region of the macula densa?
A. Isotonic compared with plasma
B. Hypotonic compared with plasma
C. Hypertonic compared with plasma
D. Hypertonic compared with plasma, in antidiuresis
B. Hypotonic compared with plasma
What effect would addition of a 1% dextrose solution have on ECF and ICF volumes, as well as osmolarity of both compartments?
Volume in both increases
Osmolarity in both decreases
A patient experiences a reduction in GFR to 25% of normal. Which of the following changes, compared with normal, would be expected in this patient, assuming steady state conditions?
A. Large increase in plasma sodium concentration
B. Reduction in urinary sodium excretion to 25% of normal
C. Reduction in urinary creatinine excretion to 25% of normal
D. Increase in serum creatinine to about 4x normal
E. Normal renal blood flow in the stenotic kidney due to autoregulation
D. Increase in serum creatinine to about 4x normal
A patient is diagnosed with a renin-secreting tumor. Which changes would you expect to find in terms of their plasma aldosterone concentration, sodium excretion rate, plasma potassium concentration, and renal blood flow assuming steady-state conditions?
Plasma aldosterone concentration increases
Sodium excretion rate does not change
Plasma potassium concentration decreases
Renal blood flow decreases
A patient presents 3 weeks after ingesting a toxin that caused sustained impairment of their proximal tubular NaCl reabsorption. Assume that there has been no change in electrolytes. What changes would you expect in their GFR, afferent arteriolar resistance, and sodium excretion?
GFR decreases
Afferent arteriolar resistance increases
Sodium excretion does not change
A young patient presents with extreme swelling of the abdomen. He appears edematous and when you check the urine you find large amounts of protein being excreted. You diagnose him with nephrotic syndrome subsequent to glomerulonephritis. What changes would you expect in interstitial fluid protein concentration, interstitial fluid hydrostatic pressure, and plasma renin concentration?
Interstitial fluid protein concentration decreases
Interstitial fluid hydrostatic pressure increases
Plasma renin concentration increases
Which of the following changes tends to increase peritubular capillary fluid reabsorption?
A. Increased BP B. Decreased FF C. Increased efferent arteriolar resistance D. Decreased angiotensin II E. Increased RBF
C. Increased efferent arteriolar resistance
A patient is referred for treatment of HTN. After testing, you discover that he has a very high level of plasma aldosterone, and your diagnosis is Conn’s syndrome. Assuming no change in electrolyte intake, what changes would you expect in urine sodium excretion and plasma renin concentration?
No change in urine Na+ excretion
Decrease in plasma renin concentration
Which of the following is associated with an atonic bladder?
A. Injury to spinal cord above sacral region, leading to lack of communication with the brain
B. Destruction of tracts that carry inhibitory impulses from the brain, but intact facilitator inputs, leading to activation of micturition by small amounts of urine
C. Destruction of afferent, sensory inputs from bladder to sacral spinal cord, leading to lack of stretch information being transferred to CNS; bladder contractions are no longer initiated
D. Destruction of both afferent and efferent fibers between bladder and cord, leading initially to cessation of bladder contraction, then later spontaneous activity of the detrusor
C. Destruction of afferent, sensory inputs from bladder to sacral spinal cord, leading to lack of stretch information being transferred to CNS; bladder contractions are no longer initiated
This is also called flaccid neuropathic bladder, may be seen in diabetes, crush injuries, syphilis, or MS
Leads to overflow incontinence, eventually bladder becomes distended and thin-walled
