Endocrine glands

Correct Answer: C

Rationale: Endocrine glands secrete hormones, chemical messengers, into the bloodstream for distant target organs, like thyroid releasing thyroxine to regulate metabolism systemically. Duct transport defines exocrine glands (e.g., sweat, sebaceous), not endocrine hormones bypass ducts. Neurotransmitters in synaptic clefts are neural, not glandular, actions (e.g., acetylcholine at synapses). Sebaceous and sweat glands are exocrine, releasing sebum or sweat externally, not hormones internally. Bloodstream delivery distinguishes endocrine function, key to their regulatory role across tissues, unlike localized or external secretions.

Correct Answer: A

Rationale: Hyperthyroidism, excess thyroid hormone (T3/T4), is treated with anti-thyroid drugs, beta blockers, or surgery not synthetic thyroid hormone (e.g., levothyroxine), which treats hypothyroidism by replacing deficient hormone. The question lacks full options, but the answer 'synthetic thyroid hormone' fits as non-treatment for excess states. This distinction clarifies therapeutic goals, reducing T3/T4 versus supplementing, critical for managing thyroid overactivity.

Correct Answer: D

Rationale: The endocrine system secretes hormones into the bloodstream, reaching distant target cells (e.g., insulin from pancreas to muscles), alters metabolism (e.g., thyroxine boosts energy use), and has prolonged effects (e.g., cortisol's stress response lasts hours), unlike rapid neural signals. Each trait holds: blood transport ensures systemic reach, metabolic shifts adapt physiology, and slow, sustained action contrasts with fleeting nerve impulses. All are true, distinguishing endocrine function as a cohesive, long-acting regulator, critical for homeostasis, unlike partial or unrelated properties.

Correct Answer: D

Rationale: The hypothalamus regulates heart rate (via autonomic nerves), temperature (thermoregulatory center), and water balance (ADH via posterior pituitary), but doesn't secrete FSH follicle-stimulating hormone comes from the anterior pituitary, stimulated by hypothalamic GnRH. Hypothalamus controls pituitary, not producing gonadotropins itself. FSH secretion's absence distinguishes it, highlighting hypothalamic oversight versus pituitary execution, critical for endocrine hierarchy.

Correct Answer: B

Rationale: Islets of Langerhans, pancreatic endocrine clusters, produce hormones (insulin, glucagon) for glucose regulation. 'Nodules' isn't specific pancreas lacks this term. Pancreas has no medulla or cortex (adrenal terms) it's mixed endocrine-exocrine. Islets' distinct cellular groups (alpha, beta) distinguish them, critical for metabolic control, unlike vague or misapplied anatomical labels.