The alpha cells of the pancreas secrete which targets the

Correct Answer: A

Rationale: Alpha cells secrete glucagon, targeting the liver to raise blood glucose via glycogenolysis and gluconeogenesis. Melatonin is pineal, calcitonin thyroid-derived, and glucagon's kidney role is secondary. Liver targeting distinguishes glucagon's function, vital for glucose homeostasis, contrasting with sleep or calcium regulators.

Correct Answer: A

Rationale: Adrenaline, from the adrenal medulla, primes the body for 'fight or flight' by boosting heart rate, glucose release, and muscle blood flow ideal for a squirrel's rapid response. Oestrogen (ovaries) and testosterone (testes) drive reproductive traits, thyroxine (thyroid) sets metabolism not acute stress. Adrenaline's rapid, systemic effects distinguish it, key to survival in danger, contrasting with long-term hormonal actions.

Correct Answer: B

Rationale: Progesterone, secreted by the corpus luteum (ovarian follicle post-ovulation), sustains pregnancy by relaxing the uterus. Pituitary regulates via LH, adrenals produce cortisol, melatonin (pineal) isn't a gland here it's a hormone. Corpus luteum's temporary endocrine role distinguishes it, critical for gestation, contrasting with permanent glands or misnamed options.

Correct Answer: D

Rationale: In hypothyroidism, low T3/T4 raises TSH via negative feedback to stimulate thyroid plasma TSH is high. Glucocorticoids suppress TSH, not directly free T4. Binding proteins (e.g., TBG) rise with oestrogens (e.g., pregnancy), not hypertension total T4 rises, free stays normal. Oestrogens increase, not decrease, total T4 via TBG. High TSH distinguishes hypothyroidism's feedback loop, critical for diagnosis, unlike glucocorticoid, binding, or oestrogen effects.

Correct Answer: D

Rationale: LH (luteinizing hormone) doesn't directly raise blood sugar it stimulates gonadal hormones (e.g., testosterone). T4 boosts metabolism, mobilizing glucose. Cortisol promotes gluconeogenesis. Growth hormone counters insulin, raising glucose. LH's reproductive focus distinguishes it, lacking metabolic impact, unlike glucose-elevating hormones.