BIOS 255 / BIOS255 Exam 3: Anatomy & Physiology III
with Lab Latest update 2026/2027 | Chamberlain |
Q&A with Rationales | Grade A | Pass Guaranteed
A+ Graded
Question 1
Which of the following statements accurately describes the function of the nephron loop (loop of
Henle)?
A. It is the primary site of glucose reabsorption.
B. It creates a concentration gradient in the renal medulla via the countercurrent multiplier.
C. It secretes aldosterone in response to low blood pressure.
D. It filters blood to form primary urine.
Answer: B
Rationale: The proximal convoluted tubule (PCT) is the primary site of glucose reabsorption,
and filtration occurs in the renal corpuscle. The nephron loop is specifically responsible for
establishing the medullary osmotic gradient through the countercurrent multiplier mechanism,
which is essential for water reabsorption later in the collecting duct.
Question 2
A patient’s blood work reveals a blood pH of 7.48, PaCO2 of 32 mmHg, and HCO3- of 24
mEq/L. Which acid-base disorder does this patient most likely have?
A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis
Answer: D
,Rationale: The pH is alkaline (>7.45). The PaCO2 is low (<35 mmHg), which indicates
hyperventilation (blowing off CO2). Since HCO3- is normal, this is an uncompensated
respiratory alkalosis.
Question 3
Which enzyme is secreted by the pancreas in an inactive form and activated in the small intestine
to digest proteins?
A. Amylase
B. Lipase
C. Trypsinogen
D. Nuclease
Answer: C
Rationale: Trypsinogen is the inactive precursor (zymogen) of trypsin. It is crucial that it is
activated in the small intestine (by enterokinase) rather than the pancreas to prevent
autodigestion of the pancreatic tissue. Amylase and lipase are often secreted in active forms,
though proteases are typically secreted as zymogens.
Question 4
During the countercurrent multiplier mechanism, where is the filtrate most dilute?
A. Descending limb of the nephron loop
B. Ascending limb of the nephron loop
C. Distal convoluted tubule
D. Collecting duct
Answer: B
Rationale: The ascending limb is impermeable to water but actively transports Na+, K+, and Cl-
into the medulla. This removes solutes without losing water, making the filtrate inside the
ascending limb dilute (hypo-osmotic) relative to the interstitial fluid.
, Question 5
Which of the following is the correct sequence of events in the Renin-Angiotensin-Aldosterone
System (RAAS) starting from a drop in blood pressure?
Angiotensin II causes vasoconstriction and stimulates aldosterone release.
Kidneys release renin.
Angiotensin I is converted to Angiotensin II.
Renin converts Angiotensinogen into Angiotensin I.
A. 1, 2, 3, 4
B. 2, 4, 3, 1
C. 4, 2, 1, 3
D. 2, 3, 4, 1
Answer: B
Rationale: The sequence begins with the kidney sensing low BP/flow and releasing renin (Step
2). Renin acts on Angiotensinogen (from the liver) to make Angiotensin I (Step 4). ACE in the
lungs converts Angiotensin I to Angiotensin II (Step 3). Angiotensin II then exerts its effects
(Step 1).
Question 6
A patient is suffering from severe hyperkalemia (high potassium). Which of the following
physiological mechanisms would the body likely activate to correct this imbalance?
A. Release of aldosterone
B. Release of ADH (antidiuretic hormone)
C. Inhibition of the Na+/K+ pump
D. Increased H+ secretion into the urine
Answer: A
with Lab Latest update 2026/2027 | Chamberlain |
Q&A with Rationales | Grade A | Pass Guaranteed
A+ Graded
Question 1
Which of the following statements accurately describes the function of the nephron loop (loop of
Henle)?
A. It is the primary site of glucose reabsorption.
B. It creates a concentration gradient in the renal medulla via the countercurrent multiplier.
C. It secretes aldosterone in response to low blood pressure.
D. It filters blood to form primary urine.
Answer: B
Rationale: The proximal convoluted tubule (PCT) is the primary site of glucose reabsorption,
and filtration occurs in the renal corpuscle. The nephron loop is specifically responsible for
establishing the medullary osmotic gradient through the countercurrent multiplier mechanism,
which is essential for water reabsorption later in the collecting duct.
Question 2
A patient’s blood work reveals a blood pH of 7.48, PaCO2 of 32 mmHg, and HCO3- of 24
mEq/L. Which acid-base disorder does this patient most likely have?
A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis
Answer: D
,Rationale: The pH is alkaline (>7.45). The PaCO2 is low (<35 mmHg), which indicates
hyperventilation (blowing off CO2). Since HCO3- is normal, this is an uncompensated
respiratory alkalosis.
Question 3
Which enzyme is secreted by the pancreas in an inactive form and activated in the small intestine
to digest proteins?
A. Amylase
B. Lipase
C. Trypsinogen
D. Nuclease
Answer: C
Rationale: Trypsinogen is the inactive precursor (zymogen) of trypsin. It is crucial that it is
activated in the small intestine (by enterokinase) rather than the pancreas to prevent
autodigestion of the pancreatic tissue. Amylase and lipase are often secreted in active forms,
though proteases are typically secreted as zymogens.
Question 4
During the countercurrent multiplier mechanism, where is the filtrate most dilute?
A. Descending limb of the nephron loop
B. Ascending limb of the nephron loop
C. Distal convoluted tubule
D. Collecting duct
Answer: B
Rationale: The ascending limb is impermeable to water but actively transports Na+, K+, and Cl-
into the medulla. This removes solutes without losing water, making the filtrate inside the
ascending limb dilute (hypo-osmotic) relative to the interstitial fluid.
, Question 5
Which of the following is the correct sequence of events in the Renin-Angiotensin-Aldosterone
System (RAAS) starting from a drop in blood pressure?
Angiotensin II causes vasoconstriction and stimulates aldosterone release.
Kidneys release renin.
Angiotensin I is converted to Angiotensin II.
Renin converts Angiotensinogen into Angiotensin I.
A. 1, 2, 3, 4
B. 2, 4, 3, 1
C. 4, 2, 1, 3
D. 2, 3, 4, 1
Answer: B
Rationale: The sequence begins with the kidney sensing low BP/flow and releasing renin (Step
2). Renin acts on Angiotensinogen (from the liver) to make Angiotensin I (Step 4). ACE in the
lungs converts Angiotensin I to Angiotensin II (Step 3). Angiotensin II then exerts its effects
(Step 1).
Question 6
A patient is suffering from severe hyperkalemia (high potassium). Which of the following
physiological mechanisms would the body likely activate to correct this imbalance?
A. Release of aldosterone
B. Release of ADH (antidiuretic hormone)
C. Inhibition of the Na+/K+ pump
D. Increased H+ secretion into the urine
Answer: A
