Biol 252 Human Anatomy & Physiology II
W/Lab | Module 5 Exam-Portage Learning
| All Questions And Solutions (Rationales)
2026 | Exam Prep Exam
1. Which of the following best describes the primary function of the endocrine system in
maintaining homeostasis compared to the nervous system?
A. The endocrine system produces fast-acting, short-duration electrical signals across synapses.
B. The endocrine system releases chemical messengers into the bloodstream that exert
widespread, longer-lasting effects on target tissues.
C. The endocrine system operates independently of feedback loops and target cell receptors.
D. The endocrine system utilizes neurotransmitters exclusively to regulate rapid reflex arcs.
Answer: B Rationale: The endocrine system secretes hormones directly into the bloodstream
to regulate metabolic, growth, and physiological processes over a longer duration, whereas
the nervous system relies on rapid electrical and synaptic neurotransmitter transmission for
immediate, short-lived responses.
2. A patient presents with elevated serum calcium levels. Which hormone is primarily
responsible for lowering blood calcium concentration by stimulating osteoblast activity and
inhibiting osteoclasts?
A. Parathyroid hormone (PTH)
B. Calcimimetic peptide
C. Calcitonin
D. Aldosterone
Answer: C Rationale: Calcitonin, secreted by the parafollicular (C) cells of the thyroid gland,
acts to reduce blood calcium levels by encouraging bone deposition through osteoblast
stimulation and reducing osteoclast-mediated bone resorption.
3. Hydrophilic hormones, such as peptide hormones and catecholamines, require which
mechanism to exert their effects on target cells?
,A. Direct diffusion across the lipid bilayer to bind nuclear receptors
B. Active transport through protein channels to directly alter intracellular DNA expression
C. Binding to plasma membrane surface receptors, activating second messenger systems such as
cAMP
D. Endocytosis followed by direct activation of mitochondrial enzymes
Answer: C Rationale: Water-soluble (hydrophilic) hormones cannot cross the hydrophobic
lipid bilayer of the cell membrane; therefore, they bind to cell-surface transmembrane
receptors and trigger intracellular cascade pathways using second messengers like cAMP or
IP3.
4. During a physical exam, a physician notes hyperpigmentation of the skin, low blood
pressure, and fatigue. Lab results indicate low levels of cortisol and elevated levels of
adrenocorticotropic hormone (ACTH). What is the most likely diagnosis?
A. Cushing's disease
B. Primary adrenal insufficiency (Addison's disease)
C. Secondary adrenal insufficiency
D. Conn's syndrome
Answer: B Rationale: Primary adrenal insufficiency occurs when the adrenal cortex fails to
produce cortisol. Due to loss of negative feedback, the anterior pituitary releases high
amounts of ACTH, which shares a precursor (POMC) with melanocyte-stimulating hormone,
causing characteristic hyperpigmentation.
5. Which structure serves as the primary neural interface connecting the central nervous
system to the endocrine system via the hypophyseal portal system?
A. Thalamus
B. Epithalamus
C. Hypothalamus
D. Pons
Answer: C Rationale: The hypothalamus synthesizes releasing and inhibiting hormones that
travel through the hypophyseal portal system to regulate the secretion of anterior pituitary
hormones, linking neurological signals to endocrine responses.
,6. Which hormone is synthesized by the hypothalamus and stored in the posterior pituitary
gland for release during uterine contractions and milk ejection?
A. Prolactin
B. Luteinizing hormone (LH)
C. Oxytocin
D. Human chorionic gonadotropin (hCG)
Answer: C Rationale: Oxytocin and antidiuretic hormone (ADH) are synthesized in the
paraventricular and supraoptic nuclei of the hypothalamus and stored in axon terminals
within the posterior pituitary (neurohypophysis) until release.
7. An adult patient exhibits coarse facial features, enlarged hands and feet, and joint pain.
Blood testing demonstrates elevated serum IGF-1 levels. Which endocrine dysfunction is
responsible for this condition?
A. Hypersecretion of growth hormone (GH) prior to epiphyseal plate closure
B. Hypersecretion of growth hormone (GH) after epiphyseal plate closure
C. Hyposecretion of thyroid hormone during early development
D. Excess release of cortisol from the adrenal zona fasciculata
Answer: B Rationale: Acromegaly results from excess growth hormone secretion after the
epiphyseal plates have fused, leading to membrane bone growth and tissue thickening
without vertical bone elongation. Hypersecretion before plate fusion causes gigantism.
8. Which zone of the adrenal cortex is correctly paired with its primary secretory product?
A. Zona glomerulosa — Glucocorticoids (Cortisol)
B. Zona fasciculata — Mineralocorticoids (Aldosterone)
C. Zona reticularis — Androgens (DHEA)
D. Adrenal medulla — Aldosterone
Answer: C Rationale: The adrenal cortex layers from superficial to deep are Zona
glomerulosa (produces mineralocorticoids/aldosterone), Zona fasciculata (produces
glucocorticoids/cortisol), and Zona reticularis (produces gonadocorticoids/androgens).
, 9. In the regulation of thyroid hormone production, what is the role of Thyroid Stimulating
Hormone (TSH)?
A. Direct inhibition of iodine uptake in follicular cells
B. Stimulation of thyroglobulin synthesis, iodine trapping, and release of T3 and T4
C. Suppression of thyroid peroxidase enzyme activity
D. Direct stimulation of parathyroid cells to release PTH
Answer: B Rationale: TSH, secreted by the anterior pituitary, binds to thyroid follicular cells
to stimulate iodine trapping, thyroglobulin iodination, and the endocytosis and enzymatic
cleavage that releases active T3 and T4 into circulation.
10. What effect does Antidiuretic Hormone (ADH) have on renal tubular function?
A. Decreases sodium reabsorption in the proximal convoluted tubule
B. Inserts aquaporin-2 channels into the apical membrane of collecting duct principal cells
C. Inhibits the Na+/K+/2Cl- cotransporter in the thick ascending limb
D. Promotes potassium reabsorption while excreting water in the loop of Henle
Answer: B Rationale: ADH (vasopressin) binds to V2 receptors on principal cells in the renal
collecting ducts, triggering intracellular cAMP signaling that inserts aquaporin-2 water
channels, thereby increasing water reabsorption and reducing urine volume.
11. A 34-year-old female experiences heat intolerance, weight loss despite increased
appetite, exophthalmos, and tremors. Serum TSH is undetectable, while free T4 is
markedly elevated. Which condition is present?
A. Hashimoto's thyroiditis
B. Graves' disease
C. Pituitary adenoma secreting TSH
D. Subacute granulomatous thyroiditis
Answer: B Rationale: Graves' disease is an autoimmune condition caused by thyroid-
stimulating immunoglobulins (TSI) that act as agonists on TSH receptors, causing autonomous
hypersecretion of thyroid hormones and suppressing endogenous pituitary TSH.
W/Lab | Module 5 Exam-Portage Learning
| All Questions And Solutions (Rationales)
2026 | Exam Prep Exam
1. Which of the following best describes the primary function of the endocrine system in
maintaining homeostasis compared to the nervous system?
A. The endocrine system produces fast-acting, short-duration electrical signals across synapses.
B. The endocrine system releases chemical messengers into the bloodstream that exert
widespread, longer-lasting effects on target tissues.
C. The endocrine system operates independently of feedback loops and target cell receptors.
D. The endocrine system utilizes neurotransmitters exclusively to regulate rapid reflex arcs.
Answer: B Rationale: The endocrine system secretes hormones directly into the bloodstream
to regulate metabolic, growth, and physiological processes over a longer duration, whereas
the nervous system relies on rapid electrical and synaptic neurotransmitter transmission for
immediate, short-lived responses.
2. A patient presents with elevated serum calcium levels. Which hormone is primarily
responsible for lowering blood calcium concentration by stimulating osteoblast activity and
inhibiting osteoclasts?
A. Parathyroid hormone (PTH)
B. Calcimimetic peptide
C. Calcitonin
D. Aldosterone
Answer: C Rationale: Calcitonin, secreted by the parafollicular (C) cells of the thyroid gland,
acts to reduce blood calcium levels by encouraging bone deposition through osteoblast
stimulation and reducing osteoclast-mediated bone resorption.
3. Hydrophilic hormones, such as peptide hormones and catecholamines, require which
mechanism to exert their effects on target cells?
,A. Direct diffusion across the lipid bilayer to bind nuclear receptors
B. Active transport through protein channels to directly alter intracellular DNA expression
C. Binding to plasma membrane surface receptors, activating second messenger systems such as
cAMP
D. Endocytosis followed by direct activation of mitochondrial enzymes
Answer: C Rationale: Water-soluble (hydrophilic) hormones cannot cross the hydrophobic
lipid bilayer of the cell membrane; therefore, they bind to cell-surface transmembrane
receptors and trigger intracellular cascade pathways using second messengers like cAMP or
IP3.
4. During a physical exam, a physician notes hyperpigmentation of the skin, low blood
pressure, and fatigue. Lab results indicate low levels of cortisol and elevated levels of
adrenocorticotropic hormone (ACTH). What is the most likely diagnosis?
A. Cushing's disease
B. Primary adrenal insufficiency (Addison's disease)
C. Secondary adrenal insufficiency
D. Conn's syndrome
Answer: B Rationale: Primary adrenal insufficiency occurs when the adrenal cortex fails to
produce cortisol. Due to loss of negative feedback, the anterior pituitary releases high
amounts of ACTH, which shares a precursor (POMC) with melanocyte-stimulating hormone,
causing characteristic hyperpigmentation.
5. Which structure serves as the primary neural interface connecting the central nervous
system to the endocrine system via the hypophyseal portal system?
A. Thalamus
B. Epithalamus
C. Hypothalamus
D. Pons
Answer: C Rationale: The hypothalamus synthesizes releasing and inhibiting hormones that
travel through the hypophyseal portal system to regulate the secretion of anterior pituitary
hormones, linking neurological signals to endocrine responses.
,6. Which hormone is synthesized by the hypothalamus and stored in the posterior pituitary
gland for release during uterine contractions and milk ejection?
A. Prolactin
B. Luteinizing hormone (LH)
C. Oxytocin
D. Human chorionic gonadotropin (hCG)
Answer: C Rationale: Oxytocin and antidiuretic hormone (ADH) are synthesized in the
paraventricular and supraoptic nuclei of the hypothalamus and stored in axon terminals
within the posterior pituitary (neurohypophysis) until release.
7. An adult patient exhibits coarse facial features, enlarged hands and feet, and joint pain.
Blood testing demonstrates elevated serum IGF-1 levels. Which endocrine dysfunction is
responsible for this condition?
A. Hypersecretion of growth hormone (GH) prior to epiphyseal plate closure
B. Hypersecretion of growth hormone (GH) after epiphyseal plate closure
C. Hyposecretion of thyroid hormone during early development
D. Excess release of cortisol from the adrenal zona fasciculata
Answer: B Rationale: Acromegaly results from excess growth hormone secretion after the
epiphyseal plates have fused, leading to membrane bone growth and tissue thickening
without vertical bone elongation. Hypersecretion before plate fusion causes gigantism.
8. Which zone of the adrenal cortex is correctly paired with its primary secretory product?
A. Zona glomerulosa — Glucocorticoids (Cortisol)
B. Zona fasciculata — Mineralocorticoids (Aldosterone)
C. Zona reticularis — Androgens (DHEA)
D. Adrenal medulla — Aldosterone
Answer: C Rationale: The adrenal cortex layers from superficial to deep are Zona
glomerulosa (produces mineralocorticoids/aldosterone), Zona fasciculata (produces
glucocorticoids/cortisol), and Zona reticularis (produces gonadocorticoids/androgens).
, 9. In the regulation of thyroid hormone production, what is the role of Thyroid Stimulating
Hormone (TSH)?
A. Direct inhibition of iodine uptake in follicular cells
B. Stimulation of thyroglobulin synthesis, iodine trapping, and release of T3 and T4
C. Suppression of thyroid peroxidase enzyme activity
D. Direct stimulation of parathyroid cells to release PTH
Answer: B Rationale: TSH, secreted by the anterior pituitary, binds to thyroid follicular cells
to stimulate iodine trapping, thyroglobulin iodination, and the endocytosis and enzymatic
cleavage that releases active T3 and T4 into circulation.
10. What effect does Antidiuretic Hormone (ADH) have on renal tubular function?
A. Decreases sodium reabsorption in the proximal convoluted tubule
B. Inserts aquaporin-2 channels into the apical membrane of collecting duct principal cells
C. Inhibits the Na+/K+/2Cl- cotransporter in the thick ascending limb
D. Promotes potassium reabsorption while excreting water in the loop of Henle
Answer: B Rationale: ADH (vasopressin) binds to V2 receptors on principal cells in the renal
collecting ducts, triggering intracellular cAMP signaling that inserts aquaporin-2 water
channels, thereby increasing water reabsorption and reducing urine volume.
11. A 34-year-old female experiences heat intolerance, weight loss despite increased
appetite, exophthalmos, and tremors. Serum TSH is undetectable, while free T4 is
markedly elevated. Which condition is present?
A. Hashimoto's thyroiditis
B. Graves' disease
C. Pituitary adenoma secreting TSH
D. Subacute granulomatous thyroiditis
Answer: B Rationale: Graves' disease is an autoimmune condition caused by thyroid-
stimulating immunoglobulins (TSI) that act as agonists on TSH receptors, causing autonomous
hypersecretion of thyroid hormones and suppressing endogenous pituitary TSH.
