BIOS 255 / BIOS255 Anatomy and
Physiology III ACTUAL EXAM
2026/2027 | BIOS 255 A&P III | Verified
Q&A | Pass Guaranteed - A+ Graded
Section 1: Endocrine System (12 Questions)
Q1: A patient presents with hyperpigmentation of the skin, hypotension, and hyponatremia. These
findings suggest dysfunction of which gland?
A. Thyroid gland
B. Parathyroid glands
C. Adrenal cortex [CORRECT]
D. Pineal gland
Correct Answer: C
Rationale: The adrenal cortex produces mineralocorticoids (primarily aldosterone) and glucocorticoids
(primarily cortisol). In Addison's disease (primary adrenal insufficiency), destruction of the adrenal
cortex leads to cortisol and aldosterone deficiency. Low cortisol stimulates ACTH release from the
anterior pituitary; ACTH is derived from pro-opiomelanocortin (POMC), which also produces
melanocyte-stimulating hormone (MSH), causing hyperpigmentation. Aldosterone deficiency causes
sodium loss (hyponatremia), potassium retention, and hypotension due to volume depletion.
Q2: Which hormone is released by the posterior pituitary but synthesized in the hypothalamus?
A. Growth hormone (GH)
B. Thyroid-stimulating hormone (TSH)
C. Antidiuretic hormone (ADH) [CORRECT]
D. Adrenocorticotropic hormone (ACTH)
Correct Answer: C
,Rationale: The posterior pituitary (neurohypophysis) does not synthesize hormones; it stores and
releases two hormones produced by neurosecretory cells in the supraoptic and paraventricular nuclei of
the hypothalamus: antidiuretic hormone (ADH/vasopressin) and oxytocin. These hormones travel down
axons via the hypothalamo-hypophyseal tract and are released in response to neural signals. ADH
increases water reabsorption in the collecting ducts of the kidneys by inserting aquaporin-2 channels.
Q3: A 45-year-old patient exhibits weight gain, moon face, buffalo hump, purple striae, and
hyperglycemia. Which hormonal imbalance is most likely responsible?
A. Excess thyroid hormone
B. Excess cortisol [CORRECT]
C. Deficient aldosterone
D. Excess growth hormone
Correct Answer: B
Rationale: Cushing's syndrome results from prolonged exposure to elevated glucocorticoid levels
(endogenous cortisol or exogenous steroid use). Cortisol promotes gluconeogenesis and decreases
peripheral glucose uptake, causing hyperglycemia. It redistributes fat to the face (moon face), upper
back/neck (buffalo hump), and trunk while causing protein catabolism (muscle wasting, thin skin, purple
striae from weakened connective tissue). Cortisol also has mineralocorticoid effects at high
concentrations, contributing to hypertension.
Q4: Which of the following hormones uses a second messenger system involving cAMP and does NOT
enter the target cell directly?
A. Cortisol
B. Aldosterone
C. Insulin [CORRECT]
D. Testosterone
Correct Answer: C
Rationale: Hormones are classified by chemical structure and mechanism of action. Peptide and protein
hormones (like insulin, GH, TSH, ACTH) are hydrophilic and cannot cross the lipid bilayer; they bind to
cell surface receptors and activate second messenger systems. Insulin binds to tyrosine kinase receptors,
initiating a phosphorylation cascade. Steroid hormones (cortisol, aldosterone, testosterone, estrogen)
and thyroid hormones are lipophilic, diffuse through the plasma membrane, and bind to intracellular
receptors that act as transcription factors to alter gene expression.
, Q5: Which hormone is released in response to low serum calcium levels?
A. Calcitonin
B. Parathyroid hormone (PTH) [CORRECT]
C. Aldosterone
D. Glucagon
Correct Answer: B
Rationale: Parathyroid hormone (PTH) is secreted by the chief cells of the parathyroid glands in direct
response to decreased blood calcium concentration. PTH raises serum calcium through three primary
mechanisms: (1) stimulating osteoclasts to resorb bone and release calcium and phosphate into the
blood; (2) increasing renal calcium reabsorption in the distal convoluted tubule while promoting
phosphate excretion; and (3) activating vitamin D to calcitriol (1,25-dihydroxyvitamin D3) in the kidneys,
which enhances intestinal calcium absorption. PTH is antagonistic to calcitonin, which lowers blood
calcium.
Q6: The alpha cells of the pancreatic islets secrete which hormone in response to low blood glucose?
A. Insulin
B. Somatostatin
C. Glucagon [CORRECT]
D. Pancreatic polypeptide
Correct Answer: C
Rationale: The pancreatic islets (islets of Langerhans) contain four primary cell types: alpha (α) cells
secrete glucagon, beta (β) cells secrete insulin, delta (δ) cells secrete somatostatin, and F cells secrete
pancreatic polypeptide. Glucagon is released when blood glucose falls below normal (hypoglycemia) and
acts primarily on the liver to stimulate glycogenolysis (breakdown of glycogen to glucose) and
gluconeogenesis (synthesis of glucose from amino acids and glycerol), thereby raising blood glucose
levels. This is a critical counter-regulatory mechanism to insulin.
Q7: Which anterior pituitary hormone stimulates the thyroid gland to produce T3 and T4?
A. Growth hormone (GH)
B. Thyroid-stimulating hormone (TSH) [CORRECT]
C. Prolactin (PRL)
D. Melanocyte-stimulating hormone (MSH)
Correct Answer: B
Physiology III ACTUAL EXAM
2026/2027 | BIOS 255 A&P III | Verified
Q&A | Pass Guaranteed - A+ Graded
Section 1: Endocrine System (12 Questions)
Q1: A patient presents with hyperpigmentation of the skin, hypotension, and hyponatremia. These
findings suggest dysfunction of which gland?
A. Thyroid gland
B. Parathyroid glands
C. Adrenal cortex [CORRECT]
D. Pineal gland
Correct Answer: C
Rationale: The adrenal cortex produces mineralocorticoids (primarily aldosterone) and glucocorticoids
(primarily cortisol). In Addison's disease (primary adrenal insufficiency), destruction of the adrenal
cortex leads to cortisol and aldosterone deficiency. Low cortisol stimulates ACTH release from the
anterior pituitary; ACTH is derived from pro-opiomelanocortin (POMC), which also produces
melanocyte-stimulating hormone (MSH), causing hyperpigmentation. Aldosterone deficiency causes
sodium loss (hyponatremia), potassium retention, and hypotension due to volume depletion.
Q2: Which hormone is released by the posterior pituitary but synthesized in the hypothalamus?
A. Growth hormone (GH)
B. Thyroid-stimulating hormone (TSH)
C. Antidiuretic hormone (ADH) [CORRECT]
D. Adrenocorticotropic hormone (ACTH)
Correct Answer: C
,Rationale: The posterior pituitary (neurohypophysis) does not synthesize hormones; it stores and
releases two hormones produced by neurosecretory cells in the supraoptic and paraventricular nuclei of
the hypothalamus: antidiuretic hormone (ADH/vasopressin) and oxytocin. These hormones travel down
axons via the hypothalamo-hypophyseal tract and are released in response to neural signals. ADH
increases water reabsorption in the collecting ducts of the kidneys by inserting aquaporin-2 channels.
Q3: A 45-year-old patient exhibits weight gain, moon face, buffalo hump, purple striae, and
hyperglycemia. Which hormonal imbalance is most likely responsible?
A. Excess thyroid hormone
B. Excess cortisol [CORRECT]
C. Deficient aldosterone
D. Excess growth hormone
Correct Answer: B
Rationale: Cushing's syndrome results from prolonged exposure to elevated glucocorticoid levels
(endogenous cortisol or exogenous steroid use). Cortisol promotes gluconeogenesis and decreases
peripheral glucose uptake, causing hyperglycemia. It redistributes fat to the face (moon face), upper
back/neck (buffalo hump), and trunk while causing protein catabolism (muscle wasting, thin skin, purple
striae from weakened connective tissue). Cortisol also has mineralocorticoid effects at high
concentrations, contributing to hypertension.
Q4: Which of the following hormones uses a second messenger system involving cAMP and does NOT
enter the target cell directly?
A. Cortisol
B. Aldosterone
C. Insulin [CORRECT]
D. Testosterone
Correct Answer: C
Rationale: Hormones are classified by chemical structure and mechanism of action. Peptide and protein
hormones (like insulin, GH, TSH, ACTH) are hydrophilic and cannot cross the lipid bilayer; they bind to
cell surface receptors and activate second messenger systems. Insulin binds to tyrosine kinase receptors,
initiating a phosphorylation cascade. Steroid hormones (cortisol, aldosterone, testosterone, estrogen)
and thyroid hormones are lipophilic, diffuse through the plasma membrane, and bind to intracellular
receptors that act as transcription factors to alter gene expression.
, Q5: Which hormone is released in response to low serum calcium levels?
A. Calcitonin
B. Parathyroid hormone (PTH) [CORRECT]
C. Aldosterone
D. Glucagon
Correct Answer: B
Rationale: Parathyroid hormone (PTH) is secreted by the chief cells of the parathyroid glands in direct
response to decreased blood calcium concentration. PTH raises serum calcium through three primary
mechanisms: (1) stimulating osteoclasts to resorb bone and release calcium and phosphate into the
blood; (2) increasing renal calcium reabsorption in the distal convoluted tubule while promoting
phosphate excretion; and (3) activating vitamin D to calcitriol (1,25-dihydroxyvitamin D3) in the kidneys,
which enhances intestinal calcium absorption. PTH is antagonistic to calcitonin, which lowers blood
calcium.
Q6: The alpha cells of the pancreatic islets secrete which hormone in response to low blood glucose?
A. Insulin
B. Somatostatin
C. Glucagon [CORRECT]
D. Pancreatic polypeptide
Correct Answer: C
Rationale: The pancreatic islets (islets of Langerhans) contain four primary cell types: alpha (α) cells
secrete glucagon, beta (β) cells secrete insulin, delta (δ) cells secrete somatostatin, and F cells secrete
pancreatic polypeptide. Glucagon is released when blood glucose falls below normal (hypoglycemia) and
acts primarily on the liver to stimulate glycogenolysis (breakdown of glycogen to glucose) and
gluconeogenesis (synthesis of glucose from amino acids and glycerol), thereby raising blood glucose
levels. This is a critical counter-regulatory mechanism to insulin.
Q7: Which anterior pituitary hormone stimulates the thyroid gland to produce T3 and T4?
A. Growth hormone (GH)
B. Thyroid-stimulating hormone (TSH) [CORRECT]
C. Prolactin (PRL)
D. Melanocyte-stimulating hormone (MSH)
Correct Answer: B
