PCB 3703 Exam 4 V2 | PCB 3703 Human
Physiology | Actual Q&A with Rationale (PCB3703
Exam 4) | University of Central Florida
1. Which of the following describes the correct sequence of fluid flow through the nephron?
A. Bowman’s capsule, Distal tubule, Loop of Henle, Proximal tubule
B. Proximal tubule, Bowman’s capsule, Distal tubule, Loop of Henle
C. Bowman’s capsule, Proximal tubule, Loop of Henle, Distal tubule
D. Glomerulus, Distal tubule, Proximal tubule, Collecting duct
Correct Answer: C
Explanation: The nephron is the functional unit of the kidney responsible for urine
formation. Filtration begins at the renal corpuscle, which consists of the glomerulus and
Bowman’s capsule. The filtrate then travels sequentially through the proximal convoluted
tubule, the descending and ascending limbs of the Loop of Henle, and finally the distal
convoluted tubule before entering the collecting duct system.
2. In the myogenic response to increased blood pressure, what is the immediate reaction of
the afferent arteriole to maintain a constant GFR?
A. Vasoconstriction to increase resistance
B. Vasodilation to increase blood flow
C. Release of Renin to increase systemic pressure
,D. Decreased firing of sympathetic nerves
Correct Answer: A
Explanation: The myogenic response is an intrinsic autoregulatory mechanism of the
kidney. When blood pressure rises, the stretch-sensitive ion channels in the afferent
arteriole smooth muscle open, leading to depolarization and contraction. This
vasoconstriction increases resistance to flow, thereby preventing the glomerular filtration
rate from rising excessively despite the higher systemic pressure.
3. Which part of the nephron is responsible for the bulk reabsorption of glucose and amino
acids via secondary active transport?
A. Distal convoluted tubule
B. Descending limb of the Loop of Henle
C. Collecting duct
D. Proximal convoluted tubule
Correct Answer: D
Explanation: The proximal convoluted tubule (PCT) is the primary site for the
reabsorption of essential solutes from the filtrate. Under normal physiological conditions,
100 percent of filtered glucose and amino acids are reabsorbed here. This process utilizes
symporters that couple the movement of these organic solutes with the downhill gradient
of sodium ions.
, 4. What is the primary function of the countercurrent multiplier system located in the Loop of
Henle?
A. To secrete excess potassium into the urine
B. To reabsorb all remaining bicarbonate ions
C. To create an osmotic gradient in the medullary interstitium
D. To decrease the hydrostatic pressure in the vasa recta
Correct Answer: C
Explanation: The countercurrent multiplier system is essential for the kidney’s ability to
concentrate urine. By utilizing the opposing flow and different permeability characteristics
of the ascending and descending limbs, it establishes a high salt concentration in the renal
medulla. This osmotic gradient allows for the passive reabsorption of water from the
collecting duct when ADH is present.
5. Antidiuretic hormone (ADH) increases water reabsorption by acting on which specific part
of the nephron?
A. Proximal tubule
B. Ascending limb of the Loop of Henle
C. Collecting duct and late distal tubule
D. Glomerular capillaries
Correct Answer: C
Physiology | Actual Q&A with Rationale (PCB3703
Exam 4) | University of Central Florida
1. Which of the following describes the correct sequence of fluid flow through the nephron?
A. Bowman’s capsule, Distal tubule, Loop of Henle, Proximal tubule
B. Proximal tubule, Bowman’s capsule, Distal tubule, Loop of Henle
C. Bowman’s capsule, Proximal tubule, Loop of Henle, Distal tubule
D. Glomerulus, Distal tubule, Proximal tubule, Collecting duct
Correct Answer: C
Explanation: The nephron is the functional unit of the kidney responsible for urine
formation. Filtration begins at the renal corpuscle, which consists of the glomerulus and
Bowman’s capsule. The filtrate then travels sequentially through the proximal convoluted
tubule, the descending and ascending limbs of the Loop of Henle, and finally the distal
convoluted tubule before entering the collecting duct system.
2. In the myogenic response to increased blood pressure, what is the immediate reaction of
the afferent arteriole to maintain a constant GFR?
A. Vasoconstriction to increase resistance
B. Vasodilation to increase blood flow
C. Release of Renin to increase systemic pressure
,D. Decreased firing of sympathetic nerves
Correct Answer: A
Explanation: The myogenic response is an intrinsic autoregulatory mechanism of the
kidney. When blood pressure rises, the stretch-sensitive ion channels in the afferent
arteriole smooth muscle open, leading to depolarization and contraction. This
vasoconstriction increases resistance to flow, thereby preventing the glomerular filtration
rate from rising excessively despite the higher systemic pressure.
3. Which part of the nephron is responsible for the bulk reabsorption of glucose and amino
acids via secondary active transport?
A. Distal convoluted tubule
B. Descending limb of the Loop of Henle
C. Collecting duct
D. Proximal convoluted tubule
Correct Answer: D
Explanation: The proximal convoluted tubule (PCT) is the primary site for the
reabsorption of essential solutes from the filtrate. Under normal physiological conditions,
100 percent of filtered glucose and amino acids are reabsorbed here. This process utilizes
symporters that couple the movement of these organic solutes with the downhill gradient
of sodium ions.
, 4. What is the primary function of the countercurrent multiplier system located in the Loop of
Henle?
A. To secrete excess potassium into the urine
B. To reabsorb all remaining bicarbonate ions
C. To create an osmotic gradient in the medullary interstitium
D. To decrease the hydrostatic pressure in the vasa recta
Correct Answer: C
Explanation: The countercurrent multiplier system is essential for the kidney’s ability to
concentrate urine. By utilizing the opposing flow and different permeability characteristics
of the ascending and descending limbs, it establishes a high salt concentration in the renal
medulla. This osmotic gradient allows for the passive reabsorption of water from the
collecting duct when ADH is present.
5. Antidiuretic hormone (ADH) increases water reabsorption by acting on which specific part
of the nephron?
A. Proximal tubule
B. Ascending limb of the Loop of Henle
C. Collecting duct and late distal tubule
D. Glomerular capillaries
Correct Answer: C
