PCB 3703 Exam 4 V3 | PCB 3703 Human
Physiology | Actual Q&A with Rationale (PCB3703
Exam 4) | University of Central Florida
1. Which of the following hormones is primarily responsible for the post-absorptive state’s
metabolic activities?
A. Glucagon
B. Insulin
C. Somatostatin
D. Gastrin
Correct Answer: A
Explanation: Glucagon is the dominant hormone during the fasted or post-absorptive
state, secreted by the alpha cells of the pancreas. Its primary role is to prevent
hypoglycemia by stimulating the liver to break down glycogen and synthesize new glucose.
This regulatory mechanism is essential for maintaining constant plasma glucose levels for
the brain and nervous system.
2. In the gastric phase of digestion, which stimulus is most responsible for the secretion of
gastrin?
A. Acidic pH in the duodenum
B. Distension of the stomach and presence of amino acids
,C. The sight and smell of food
D. Presence of fats in the ileum
Correct Answer: B
Explanation: The gastric phase is triggered by the arrival of food in the stomach, causing
mechanical distension and the chemical presence of peptides. G cells in the stomach
mucosa respond to these stimuli by secreting gastrin into the bloodstream. Gastrin then
travels to parietal cells to stimulate the release of hydrochloric acid, facilitating protein
digestion.
3. Which cell type in the testes is responsible for producing testosterone in response to
Luteinizing Hormone (LH)?
A. Sertoli cells
B. Chief cells
C. Spermatogonia
D. Leydig cells
Correct Answer: D
Explanation: Leydig cells, also known as interstitial cells, are located between the
seminiferous tubules and possess receptors for LH. When LH binds, it stimulates the
enzymatic conversion of cholesterol into testosterone. This androgen is vital for both the
development of male secondary sex characteristics and the support of spermatogenesis.
, 4. A patient presents with a goiter and high levels of TSH but low levels of T4. Which
condition is most likely?
A. Graves’ disease
B. Primary hypothyroidism
C. Cushing’s Syndrome
D. Secondary hyperthyroidism
Correct Answer: B
Explanation: Primary hypothyroidism occurs when the thyroid gland itself fails to produce
sufficient thyroid hormones despite high stimulation. Because T3 and T4 levels are low,
there is a lack of negative feedback to the anterior pituitary, leading to elevated TSH levels.
The chronic elevation of TSH often causes the thyroid gland to enlarge, resulting in a goiter.
5. What is the primary function of the hormone cholecystokinin (CCK) in the digestive
process?
A. To increase gastric motility
B. To stimulate gallbladder contraction and pancreatic enzyme secretion
C. To stimulate bicarbonate secretion from the pancreas
D. To decrease the absorption of amino acids
Correct Answer: B
Physiology | Actual Q&A with Rationale (PCB3703
Exam 4) | University of Central Florida
1. Which of the following hormones is primarily responsible for the post-absorptive state’s
metabolic activities?
A. Glucagon
B. Insulin
C. Somatostatin
D. Gastrin
Correct Answer: A
Explanation: Glucagon is the dominant hormone during the fasted or post-absorptive
state, secreted by the alpha cells of the pancreas. Its primary role is to prevent
hypoglycemia by stimulating the liver to break down glycogen and synthesize new glucose.
This regulatory mechanism is essential for maintaining constant plasma glucose levels for
the brain and nervous system.
2. In the gastric phase of digestion, which stimulus is most responsible for the secretion of
gastrin?
A. Acidic pH in the duodenum
B. Distension of the stomach and presence of amino acids
,C. The sight and smell of food
D. Presence of fats in the ileum
Correct Answer: B
Explanation: The gastric phase is triggered by the arrival of food in the stomach, causing
mechanical distension and the chemical presence of peptides. G cells in the stomach
mucosa respond to these stimuli by secreting gastrin into the bloodstream. Gastrin then
travels to parietal cells to stimulate the release of hydrochloric acid, facilitating protein
digestion.
3. Which cell type in the testes is responsible for producing testosterone in response to
Luteinizing Hormone (LH)?
A. Sertoli cells
B. Chief cells
C. Spermatogonia
D. Leydig cells
Correct Answer: D
Explanation: Leydig cells, also known as interstitial cells, are located between the
seminiferous tubules and possess receptors for LH. When LH binds, it stimulates the
enzymatic conversion of cholesterol into testosterone. This androgen is vital for both the
development of male secondary sex characteristics and the support of spermatogenesis.
, 4. A patient presents with a goiter and high levels of TSH but low levels of T4. Which
condition is most likely?
A. Graves’ disease
B. Primary hypothyroidism
C. Cushing’s Syndrome
D. Secondary hyperthyroidism
Correct Answer: B
Explanation: Primary hypothyroidism occurs when the thyroid gland itself fails to produce
sufficient thyroid hormones despite high stimulation. Because T3 and T4 levels are low,
there is a lack of negative feedback to the anterior pituitary, leading to elevated TSH levels.
The chronic elevation of TSH often causes the thyroid gland to enlarge, resulting in a goiter.
5. What is the primary function of the hormone cholecystokinin (CCK) in the digestive
process?
A. To increase gastric motility
B. To stimulate gallbladder contraction and pancreatic enzyme secretion
C. To stimulate bicarbonate secretion from the pancreas
D. To decrease the absorption of amino acids
Correct Answer: B
