Cushing's disease is a disorder caused by

Correct Answer: B

Rationale: Cushing's disease results from excess cortisol, often from pituitary ACTH overproduction, causing weight gain, hypertension, and bone loss. Low cortisol (Addison's) or aldosterone imbalances (Conn's syndrome) differ. High cortisol's systemic effects distinguish Cushing's, critical for diagnosis, contrasting with deficiencies or mineralocorticoid issues.

Correct Answer: C

Rationale: TSH (thyroid-stimulating hormone) from the anterior pituitary stimulates thyroid hormone release, regulating metabolism. ADH (vasopressin) and oxytocin, made in the hypothalamus, are stored/released by the posterior pituitary, managing water and lactation. Cortisol, an adrenal cortex glucocorticoid, responds to anterior pituitary ACTH, not a pituitary hormone itself. TSH's anterior origin and tropic role distinguish it, essential for pituitary-thyroid axis, unlike posterior or target gland products.

Correct Answer: C

Rationale: Mineralocorticoids, primarily aldosterone, are synthesized in the adrenal cortex's zona glomerulosa, regulating sodium/potassium balance and blood pressure. Parafollicular cells (thyroid C-cells) produce calcitonin for calcium, not mineralocorticoids. Zona reticularis and fasciculata collaborate reticularis makes androgens, fasciculata glucocorticoids (e.g., cortisol), not mineralocorticoids, though some overlap exists. Zona glomerulosa's outer-layer specificity for aldosterone distinguishes it, critical for electrolyte homeostasis, unlike thyroid or other adrenal zones' roles.

Correct Answer: C

Rationale: Simmond's disease, panhypopituitarism, results from pituitary damage (e.g., infarction), reducing hormone output, causing low stimulation of target glands (thyroid, adrenals, gonads). Excess GH is gigantism, renal ADH issues are diabetes insipidus, and prolactin excess is hyperprolactinemia. Low target gland activity distinguishes Simmond's, key to multi-hormone deficiency, contrasting with excess or renal disorders.

Correct Answer: C

Rationale: Beta cells in pancreatic islets secrete insulin, lowering blood glucose by driving cellular uptake and glycogen storage. Delta cells release somatostatin, inhibiting other hormones. Alpha cells produce glucagon, raising glucose. 'Gamma' isn't a pancreatic cell type possibly a typo (Q4 lists 'beta' twice). Beta cells' insulin role distinguishes them, critical for glucose homeostasis, unlike inhibitory or glucose-elevating cells.