ATI RN
Endocrine System Multiple Choice Questions Questions
Question 1 of 5
Calcium level in the blood is regulated by the:
Correct Answer: A
Rationale: The parathyroid glands secrete PTH to raise blood calcium via bone resorption and kidney reabsorption, while the thyroid's calcitonin lowers it by inhibiting resorption. Adrenal medulla (catecholamines), pancreas (insulin), testes (testosterone), and thymus (immunity) don't regulate calcium. Parathyroid-thyroid balance distinguishes this control, key to skeletal and metabolic homeostasis.
Question 2 of 5
Which of the following produce antagonistic results?
Correct Answer: A
Rationale: Calcitonin (thyroid) lowers blood calcium, parathyroid hormone (PTH) raises it antagonistic for calcium balance. FSH and LH cooperate in reproduction, ADH and vasopressin are the same, oxytocin/prolactin synergize in lactation. Calcitonin-PTH opposition distinguishes them, key to homeostasis, contrasting with synergistic pairs.
Question 3 of 5
Which hormone produced by the thyroid gland regulates blood calcium levels?
Correct Answer: D
Rationale: Calcitonin, from the thyroid's C-cells, lowers blood calcium by inhibiting osteoclasts, which break down bone. MSH (pituitary) affects pigmentation, oxytocin (hypothalamus/pituitary) aids childbirth, vasopressin (same) regulates water not calcium. Calcitonin's calcium-lowering action distinguishes it, vital for skeletal balance, especially in growth or pregnancy, contrasting with thyroid's metabolic hormones (T3/T4) or unrelated regulators.
Question 4 of 5
The sleep-wake cycle of the body is regulated by the hormone
Correct Answer: D
Rationale: Melatonin, from the pineal gland, regulates the sleep-wake cycle, increasing in darkness to promote sleep. Prolactin (pituitary) aids lactation, cortisol (adrenals) manages stress, progesterone (ovaries) supports pregnancy not sleep directly. Melatonin's circadian role distinguishes it, key to biological rhythms, with disruptions affecting sleep, unlike stress or reproductive hormones.
Question 5 of 5
ANP
Correct Answer: D
Rationale: Atrial natriuretic peptide (ANP), from stretched atria, counters angiotensin II by promoting natriuresis, vasodilation, and lowering blood pressure, opposing angiotensin II's sodium retention and vasoconstriction. It inhibits vasopressin (ADH), not stimulates. Scuba diving (pressure) may increase ANP via atrial stretch, not decrease. ANP is a single-chain peptide, not dual helix. Its antagonistic action distinguishes it, key to fluid balance, unlike vasopressin support, diving effects, or structural claims.