Aim to answer every question before checking. Missed questions point you to the sections you need most.
1. (5.1) Peptide hormones typically act by:
A. Peptides (hydrophilic) cannot cross the membrane; they bind cell-surface receptors (often GPCRs or RTKs) that generate second messengers (cAMP, IP3/DAG). Response is fast but transient.
2. (5.1) Steroid hormones:
D. Cholesterol-derived steroids (cortisol, aldosterone, sex steroids) are lipid-soluble, diffuse in, and bind cytoplasmic/nuclear receptors. The resulting complex modulates transcription - slow onset, long duration.
3. (5.2) The posterior pituitary secretes:
B. ADH and oxytocin are made in hypothalamic neurons (supraoptic and paraventricular nuclei), shipped down axons, and released from the posterior pituitary. The anterior pituitary makes ACTH, GH, TSH, FSH, LH, and prolactin.
4. (5.2) The anterior pituitary is controlled by:
C. The hypothalamic-hypophyseal portal system carries releasing hormones (TRH, GnRH, CRH, etc.) a short distance to the anterior pituitary - a small blood volume, but high concentration locally.
5. (5.3) Thyroid hormones (T3 and T4) primarily function to:
A. T3 is the active form (T4 is converted peripherally). Both bind nuclear receptors to boost oxidative metabolism, heat production, and growth. Calcitonin (from parafollicular C cells) lowers blood calcium.
6. (5.3) Parathyroid hormone (PTH) acts to:
D. PTH is the chief Ca²⁺-raising hormone. It activates osteoclasts (indirectly), increases Ca²⁺ reabsorption in the distal tubule, and stimulates 1α-hydroxylation of vitamin D, boosting gut Ca²⁺ uptake.
7. (5.4) The adrenal cortex secretes:
B. "Salt, sugar, sex": zona glomerulosa → aldosterone (salt); zona fasciculata → cortisol (sugar); zona reticularis → androgens (sex). Catecholamines come from the medulla.
8. (5.4) Aldosterone acts to:
C. Aldosterone (the main mineralocorticoid) upregulates ENaC and Na⁺/K⁺-ATPase in principal cells, retaining sodium (and water) while dumping potassium. It raises BP.
9. (5.5) Beta cells of the pancreatic islets secrete:
D. β cells = insulin (B for Beta, B for Blood glucose lowered). α cells = glucagon. δ cells = somatostatin. PP cells = pancreatic polypeptide.
10. (5.5) Glucagon, secreted by α cells, primarily:
A. Glucagon is insulin's counter-regulatory partner. During fasting it tells the liver to break down glycogen and synthesize new glucose, keeping serum levels stable.
11. (5.6) In males, LH acts on which cells to stimulate testosterone production?
B. LH → Leydig cells → testosterone. FSH → Sertoli cells → supports spermatogenesis and produces inhibin. Mnemonic: "LH Leydig, FSH Sertoli."
12. (5.6) In females, FSH primarily:
C. FSH drives follicle maturation early in the cycle. Granulosa cells convert theca-derived androgens into estradiol via aromatase. The LH surge (not FSH) triggers ovulation.
13. (5.7) The pineal gland secretes:
A. Pineal melatonin rises at night in response to darkness via the retina-SCN pathway and helps entrain sleep-wake cycles.
14. (5.7) Erythropoietin (EPO) is secreted by the kidneys in response to:
D. Renal peritubular cells sense O₂ via HIF-α. When O₂ is low, EPO rises and stimulates bone marrow to produce red blood cells.
15. (5.8) Negative feedback in the HPT axis means:
B. Classic endocrine negative feedback: the final hormone shuts down the upstream releasing hormones when levels are high. This keeps the system near setpoint.
16. (5.8) Positive feedback, as seen before ovulation, means:
C. Mid-cycle estrogen crosses a threshold and flips from negative to positive feedback on the hypothalamus/pituitary, producing an LH surge that triggers ovulation.
17. (5.9) Type 1 diabetes mellitus is caused by:
D. T1D typically presents in childhood with absolute insulin deficiency. Patients require lifelong exogenous insulin. Type 2 is resistance at target tissues (A).
18. (5.9) Hypothyroidism classically presents with:
A. Low thyroid hormone = slow metabolism = cold, heavy, sluggish. Answer B is the hyperthyroid picture (Graves disease).
19. (5.10) Water-soluble peptide and amine hormones generally travel in plasma:
B. Hydrophilic hormones travel free in aqueous plasma. Because they need no carrier, they have short half-lives (seconds to minutes).
20. (5.10) Steroid and thyroid hormones travel in plasma primarily:
C. Lipophilic hormones need protein carriers to stay in solution, which also prolongs half-life. Only the small free fraction is biologically active.
21. (5.2) Growth hormone (GH) is released from the:
A. GH is an anterior-pituitary hormone. It acts directly on tissues and indirectly through hepatic IGF-1 to drive growth. Excess in children → gigantism; in adults → acromegaly.
22. (5.4) The major effects of cortisol include:
D. Cortisol is the classic stress glucocorticoid: it raises glucose (gluconeogenesis), mobilizes fuel stores, and broadly suppresses inflammation/immunity.
23. (5.8) Tropic hormones are best defined as hormones that:
C. Tropic hormones (TSH, ACTH, FSH, LH) target other endocrine glands and make them secrete their own hormones. Direct-acting hormones target non-endocrine tissues.
24. (5.9) Cushing's syndrome is caused by:
B. Cushing's = too much cortisol. Features: central obesity, moon face, buffalo hump, stretch marks, hyperglycemia, bone loss, immune suppression.
