Which of the following statements about glucocorticoids is/are true?

Correct Answer: D

Rationale: Glucocorticoids' truths: cortisol is the primary human glucocorticoid, managing stress and glucose; they're secreted by the adrenal cortex's zona fasciculata, regulated by ACTH; in Addison's disease (adrenal insufficiency), their secretion drops, causing metabolic issues. All statements hold cortisol's dominance, fasciculata origin, and Addison's reduction align with physiology. No single statement trumps; their collective accuracy distinguishes them, key to adrenal function understanding.

Correct Answer: C

Rationale: Low growth hormone (GH) in adults isn't abnormal GH peaks in youth for growth, declining naturally post-epiphyseal closure, with minimal adult roles (metabolism, muscle maintenance). Bone abnormalities (e.g., acromegaly) stem from GH excess, not deficit. Growth spurts require high GH pre-closure, impossible in adults. Health concerns (e.g., fatigue) may arise, but low GH is typical, not alarming. Its normal adult decline distinguishes it, key to age-related endocrine shifts, unlike excess or juvenile effects.

Correct Answer: B

Rationale: The hypothalamus connects to the posterior pituitary via nerve axons in the hypothalamohypophyseal tract. These axons transport antidiuretic hormone (ADH) and oxytocin, synthesized in hypothalamic neurons, for release. Blood vessels link the anterior pituitary, not posterior, while cartilage and bone are structural, not functional connectors. This axonal bridge distinguishes posterior pituitary control, key to neurohormone secretion in fluid and reproductive regulation.

Correct Answer: B

Rationale: Hyperparathyroidism, excess PTH, overstimulates osteoclasts, weakening bones and risking fractures by elevating blood calcium. Bone deposition decreases, and convulsions may occur from hypocalcemia (opposite condition), not hypercalcemia. 'All' is incorrect. Fractures distinguish this pathology, key to diagnosing skeletal effects of prolonged PTH elevation, contrasting with deposition or neurological symptoms.

Correct Answer: A

Rationale: Human placental lactogen (hPL), from the placenta, prepares breasts for lactation by stimulating mammary growth and shifts maternal metabolism to favor fetal nutrition. It doesn't nourish the placenta or regulate menstruation (absent in pregnancy). 'All' is incorrect. Breast preparation distinguishes hPL's role, vital for postpartum milk production, contrasting with placental or cycle functions.