SCI 221 Exam 4 V2 | SCI 221 Human
Physiology with Intervention Skill-Based
(ISB) Experiential Learning | Q&A with
Rationale (SCI221 Exam 4) | Nightingale
College
1. Which hormone is primarily responsible for the insertion of aquaporins into the
membranes of the collecting ducts to increase water reabsorption?
A. Aldosterone
B. Atrial Natriuretic Peptide (ANP)
C. Antidiuretic Hormone (ADH)
D. Cortisol
Correct Answer: C
Rationale: Antidiuretic Hormone (ADH), also known as vasopressin, acts on the V2
receptors of the collecting duct cells. This interaction triggers the translocation of
aquaporin-2 channels to the apical membrane, facilitating water movement back into the
blood. Without this hormone, the collecting duct remains impermeable to water, resulting
in dilute urine production.
2. What is the primary physiological trigger for the release of Renin by the juxtaglomerular
cells?
A. Increased plasma osmolarity
,B. Decreased blood pressure or reduced sodium delivery to the macula densa
C. Elevated blood pressure in the afferent arteriole
D. High levels of circulating atrial natriuretic peptide
Correct Answer: B
Rationale: Renin is released when the juxtaglomerular apparatus detects a drop in blood
pressure or a decrease in sodium chloride concentration in the distal tubule. This enzyme
initiates the RAAS cascade by converting angiotensinogen into angiotensin I. The ultimate
goal is to restore systemic blood pressure and fluid balance through vasoconstriction and
sodium retention.
3. In the regulation of blood calcium, which hormone is secreted in response to hypocalcemia
to increase osteoclast activity?
A. Calcitonin
B. Thyroid hormone
C. Parathyroid Hormone (PTH)
D. Aldosterone
Correct Answer: C
Rationale: Parathyroid Hormone (PTH) is released by the parathyroid glands when blood
calcium levels fall below homeostatic ranges. It stimulates osteoclasts to break down bone
matrix, releasing calcium into the bloodstream, and also enhances calcium reabsorption in
, the kidneys. Additionally, PTH promotes the final activation of Vitamin D to increase
intestinal calcium absorption.
4. Which component of the nephron is the site where the majority of glucose and amino acids
are reabsorbed from the filtrate?
A. Distal convoluted tubule
B. Proximal convoluted tubule
C. Loop of Henle
D. Collecting duct
Correct Answer: B
Rationale: The proximal convoluted tubule (PCT) is responsible for reabsorbing
approximately 100% of filtered glucose and amino acids under normal physiological
conditions. This process occurs via secondary active transport coupled with sodium ions. If
blood glucose levels exceed the renal threshold, these transporters become saturated, and
glucose appears in the urine.
5. A patient is diagnosed with metabolic alkalosis. Which of the following respiratory
compensations would you expect to observe?
A. Increased respiratory rate (hyperventilation)
B. Kussmaul breathing
C. No change in respiratory patterns
Physiology with Intervention Skill-Based
(ISB) Experiential Learning | Q&A with
Rationale (SCI221 Exam 4) | Nightingale
College
1. Which hormone is primarily responsible for the insertion of aquaporins into the
membranes of the collecting ducts to increase water reabsorption?
A. Aldosterone
B. Atrial Natriuretic Peptide (ANP)
C. Antidiuretic Hormone (ADH)
D. Cortisol
Correct Answer: C
Rationale: Antidiuretic Hormone (ADH), also known as vasopressin, acts on the V2
receptors of the collecting duct cells. This interaction triggers the translocation of
aquaporin-2 channels to the apical membrane, facilitating water movement back into the
blood. Without this hormone, the collecting duct remains impermeable to water, resulting
in dilute urine production.
2. What is the primary physiological trigger for the release of Renin by the juxtaglomerular
cells?
A. Increased plasma osmolarity
,B. Decreased blood pressure or reduced sodium delivery to the macula densa
C. Elevated blood pressure in the afferent arteriole
D. High levels of circulating atrial natriuretic peptide
Correct Answer: B
Rationale: Renin is released when the juxtaglomerular apparatus detects a drop in blood
pressure or a decrease in sodium chloride concentration in the distal tubule. This enzyme
initiates the RAAS cascade by converting angiotensinogen into angiotensin I. The ultimate
goal is to restore systemic blood pressure and fluid balance through vasoconstriction and
sodium retention.
3. In the regulation of blood calcium, which hormone is secreted in response to hypocalcemia
to increase osteoclast activity?
A. Calcitonin
B. Thyroid hormone
C. Parathyroid Hormone (PTH)
D. Aldosterone
Correct Answer: C
Rationale: Parathyroid Hormone (PTH) is released by the parathyroid glands when blood
calcium levels fall below homeostatic ranges. It stimulates osteoclasts to break down bone
matrix, releasing calcium into the bloodstream, and also enhances calcium reabsorption in
, the kidneys. Additionally, PTH promotes the final activation of Vitamin D to increase
intestinal calcium absorption.
4. Which component of the nephron is the site where the majority of glucose and amino acids
are reabsorbed from the filtrate?
A. Distal convoluted tubule
B. Proximal convoluted tubule
C. Loop of Henle
D. Collecting duct
Correct Answer: B
Rationale: The proximal convoluted tubule (PCT) is responsible for reabsorbing
approximately 100% of filtered glucose and amino acids under normal physiological
conditions. This process occurs via secondary active transport coupled with sodium ions. If
blood glucose levels exceed the renal threshold, these transporters become saturated, and
glucose appears in the urine.
5. A patient is diagnosed with metabolic alkalosis. Which of the following respiratory
compensations would you expect to observe?
A. Increased respiratory rate (hyperventilation)
B. Kussmaul breathing
C. No change in respiratory patterns
