Glucagon acts on the ___ to convert glycogen into glucose.

Correct Answer: A

Rationale: Glucagon targets liver hepatocytes for glycogenolysis, not pancreas (secretion site) or muscle (lacking receptors). 'A' inferred. This distinguishes glucagon's hepatic role, vital for glucose release, contrasting with insulin's broader targets.

Correct Answer: B

Rationale: ADH (vasopressin) targets kidneys (water reabsorption via aquaporins) and blood vessels (vasoconstriction) raises blood pressure/volume. Adrenal cortex (aldosterone) and liver (metabolism) aren't ADH targets different systems. Liver-kidney omits vessels. Pituitary releases ADH, thyroid is unrelated. Kidney-vessel dual action distinguishes ADH, critical for fluid balance, unlike endocrine or metabolic pairs.

Correct Answer: D

Rationale: ACTH from anterior pituitary stimulates adrenal cortex to release cortisol/glucocorticoids stress response. Anterior pituitary makes ACTH, not target. Adrenal medulla (epinephrine) is neural. Kidneys respond to aldosterone, not ACTH directly. Adrenal cortex's ACTH-driven output distinguishes it, key to HPA axis, unlike source, neural, or renal options.

Correct Answer: A

Rationale: Hashimoto's disease is autoimmune hypothyroidism thyroid destruction lowers T3/T4, causing myxedema-like symptoms. Graves is autoimmune hyperthyroidism overactivity. Myxedema is hypothyroidism's result, not cause. Acromegaly is GH-related, unrelated. Hashimoto's autoimmune basis distinguishes it, key to thyroid failure, unlike hyper, symptomatic, or growth disorders.

Correct Answer: D

Rationale: Aldosterone, from adrenal cortex's zona glomerulosa, is the primary mineralocorticoid regulates sodium/potassium, blood volume. Cortisol (fasciculata) is a glucocorticoid, minor mineral effect. Glucagon (pancreas) raises glucose, unrelated. Epinephrine (medulla) is catecholamine, not steroid. Aldosterone's electrolyte focus distinguishes it, critical for pressure/fluid balance, unlike glucose or stress hormones.