BIOL251 Human Anatomy & Physiology I w/Lab 2025/2026| Module 8 Exam
Review |100+ Questions and Answers Summary / Endocrine System
Questions 1–20: Hormone Chemistry & Mechanisms
1. Which of the following is a catecholamine hormone?
a) Insulin
b) Cortisol
c) Epinephrine
d) Thyroxine
Answer: c) Epinephrine
Rationale: Catecholamines (epinephrine, norepinephrine, dopamine) are derived from
tyrosine and are water-soluble.
2. Thyroid hormones (T3/T4) are synthesized from which amino acid?
a) Tryptophan
b) Tyrosine
c) Histidine
d) Methionine
Answer: b) Tyrosine
Rationale: Thyroid hormones are iodinated derivatives of tyrosine.
3. Peptide hormones typically act through:
a) Intracellular receptors
b) Membrane-bound G-protein coupled receptors
c) Direct DNA binding
d) Nuclear receptors only
Answer: b) Membrane-bound G-protein coupled receptors
Rationale: Peptide hormones are water-soluble and cannot cross the plasma membrane;
they bind surface receptors.
4. Which steroid hormone is produced by the adrenal cortex?
a) Epinephrine
,b) Aldosterone
c) Melatonin
d) Oxytocin
Answer: b) Aldosterone
Rationale: Aldosterone is a mineralocorticoid from the adrenal cortex.
5. The second messenger cAMP is generated by activation of:
a) Guanylyl cyclase
b) Adenylate cyclase
c) Phospholipase C
d) Tyrosine kinase
Answer: b) Adenylate cyclase
Rationale: Gs protein activates adenylate cyclase → converts ATP to cAMP.
6. Which hormone uses the JAK-STAT signaling pathway?
a) Insulin
b) Growth hormone
c) Epinephrine
d) Testosterone
Answer: b) Growth hormone
Rationale: GH binds cytokine receptors, activating JAK-STAT.
7. Hormones that are derived from cholesterol are called:
a) Peptides
b) Biogenic amines
c) Steroids
d) Eicosanoids
Answer: c) Steroids
Rationale: Steroid hormones (cortisol, aldosterone, sex hormones) are cholesterol
derivatives.
8. Prolactin is classified as a:
a) Steroid
,b) Monoamine
c) Peptide hormone
d) Thyroid hormone
Answer: c) Peptide hormone
Rationale: Prolactin is a protein hormone from the anterior pituitary.
9. Which of the following is an example of a hormone that acts via a nuclear receptor?
a) Epinephrine
b) Oxytocin
c) Estrogen
d) Insulin
Answer: c) Estrogen
Rationale: Estrogen is a steroid that binds intracellular/nuclear receptors.
10. The half-life of steroid hormones is generally _____ than peptide hormones.
a) Shorter
b) Longer
c) Equal
d) Unpredictable
Answer: b) Longer
Rationale: Steroids bind carrier proteins, slowing metabolism.
11. Which enzyme converts angiotensin I to angiotensin II?
a) Renin
b) ACE
c) Chymase
d) Carboxypeptidase
Answer: b) ACE (Angiotensin-converting enzyme)
Rationale: ACE in lung endothelium cleaves angiotensin I to active angiotensin II.
12. The pituitary hormone that stimulates milk production is:
a) Oxytocin
b) ADH
, c) Prolactin
d) LH
Answer: c) Prolactin
Rationale: Prolactin acts on mammary glands for lactogenesis.
13. Growth hormone-releasing hormone (GHRH) is secreted by the:
a) Posterior pituitary
b) Hypothalamus
c) Thyroid
d) Pancreas
Answer: b) Hypothalamus
Rationale: GHRH from hypothalamus stimulates anterior pituitary GH release.
14. Which hormone is stored in the posterior pituitary but synthesized in the hypothalamus?
a) TSH
b) ACTH
c) ADH
d) MSH
Answer: c) ADH (Vasopressin)
Rationale: ADH and oxytocin are made in hypothalamus, stored in posterior pituitary.
15. A blood test reveals high levels of T4 but low TSH. This suggests:
a) Primary hypothyroidism
b) Secondary hyperthyroidism
c) Primary hyperthyroidism
d) Pituitary tumor secreting TSH
Answer: c) Primary hyperthyroidism
Rationale: High T4 suppresses TSH via negative feedback (Graves’ disease).
16. Calcitonin is produced by which cells of the thyroid?
a) Follicular cells
b) Parafollicular C cells
Review |100+ Questions and Answers Summary / Endocrine System
Questions 1–20: Hormone Chemistry & Mechanisms
1. Which of the following is a catecholamine hormone?
a) Insulin
b) Cortisol
c) Epinephrine
d) Thyroxine
Answer: c) Epinephrine
Rationale: Catecholamines (epinephrine, norepinephrine, dopamine) are derived from
tyrosine and are water-soluble.
2. Thyroid hormones (T3/T4) are synthesized from which amino acid?
a) Tryptophan
b) Tyrosine
c) Histidine
d) Methionine
Answer: b) Tyrosine
Rationale: Thyroid hormones are iodinated derivatives of tyrosine.
3. Peptide hormones typically act through:
a) Intracellular receptors
b) Membrane-bound G-protein coupled receptors
c) Direct DNA binding
d) Nuclear receptors only
Answer: b) Membrane-bound G-protein coupled receptors
Rationale: Peptide hormones are water-soluble and cannot cross the plasma membrane;
they bind surface receptors.
4. Which steroid hormone is produced by the adrenal cortex?
a) Epinephrine
,b) Aldosterone
c) Melatonin
d) Oxytocin
Answer: b) Aldosterone
Rationale: Aldosterone is a mineralocorticoid from the adrenal cortex.
5. The second messenger cAMP is generated by activation of:
a) Guanylyl cyclase
b) Adenylate cyclase
c) Phospholipase C
d) Tyrosine kinase
Answer: b) Adenylate cyclase
Rationale: Gs protein activates adenylate cyclase → converts ATP to cAMP.
6. Which hormone uses the JAK-STAT signaling pathway?
a) Insulin
b) Growth hormone
c) Epinephrine
d) Testosterone
Answer: b) Growth hormone
Rationale: GH binds cytokine receptors, activating JAK-STAT.
7. Hormones that are derived from cholesterol are called:
a) Peptides
b) Biogenic amines
c) Steroids
d) Eicosanoids
Answer: c) Steroids
Rationale: Steroid hormones (cortisol, aldosterone, sex hormones) are cholesterol
derivatives.
8. Prolactin is classified as a:
a) Steroid
,b) Monoamine
c) Peptide hormone
d) Thyroid hormone
Answer: c) Peptide hormone
Rationale: Prolactin is a protein hormone from the anterior pituitary.
9. Which of the following is an example of a hormone that acts via a nuclear receptor?
a) Epinephrine
b) Oxytocin
c) Estrogen
d) Insulin
Answer: c) Estrogen
Rationale: Estrogen is a steroid that binds intracellular/nuclear receptors.
10. The half-life of steroid hormones is generally _____ than peptide hormones.
a) Shorter
b) Longer
c) Equal
d) Unpredictable
Answer: b) Longer
Rationale: Steroids bind carrier proteins, slowing metabolism.
11. Which enzyme converts angiotensin I to angiotensin II?
a) Renin
b) ACE
c) Chymase
d) Carboxypeptidase
Answer: b) ACE (Angiotensin-converting enzyme)
Rationale: ACE in lung endothelium cleaves angiotensin I to active angiotensin II.
12. The pituitary hormone that stimulates milk production is:
a) Oxytocin
b) ADH
, c) Prolactin
d) LH
Answer: c) Prolactin
Rationale: Prolactin acts on mammary glands for lactogenesis.
13. Growth hormone-releasing hormone (GHRH) is secreted by the:
a) Posterior pituitary
b) Hypothalamus
c) Thyroid
d) Pancreas
Answer: b) Hypothalamus
Rationale: GHRH from hypothalamus stimulates anterior pituitary GH release.
14. Which hormone is stored in the posterior pituitary but synthesized in the hypothalamus?
a) TSH
b) ACTH
c) ADH
d) MSH
Answer: c) ADH (Vasopressin)
Rationale: ADH and oxytocin are made in hypothalamus, stored in posterior pituitary.
15. A blood test reveals high levels of T4 but low TSH. This suggests:
a) Primary hypothyroidism
b) Secondary hyperthyroidism
c) Primary hyperthyroidism
d) Pituitary tumor secreting TSH
Answer: c) Primary hyperthyroidism
Rationale: High T4 suppresses TSH via negative feedback (Graves’ disease).
16. Calcitonin is produced by which cells of the thyroid?
a) Follicular cells
b) Parafollicular C cells
