Which of the following is NOT a major endocrine organ, but produces hormones in addition to its major function?

Correct Answer: C

Rationale: The correct answer is C: kidneys. The kidneys are not considered a major endocrine organ, but they do produce hormones such as erythropoietin and renin as part of their major function of regulating fluid balance and blood pressure. The pancreas (A) is a major endocrine organ producing insulin and glucagon. The thymus (B) is involved in immune function and produces hormones like thymosin. The pituitary (D) is often referred to as the master gland and secretes various hormones that regulate other endocrine glands.

Correct Answer: B

Rationale: The correct answer is B: Inferior phrenic artery. The superior suprarenal artery arises from the inferior phrenic artery, which supplies blood to the adrenal gland. The inferior phrenic artery originates from the abdominal aorta, near the celiac trunk. It is important to note that the adrenal glands receive blood supply from multiple sources, including the inferior phrenic artery. The other choices (A: Abdominal aorta, C: Renal artery, D: Superior mesenteric artery) do not directly supply blood to the adrenal glands, making them incorrect options.

Correct Answer: D

Rationale: The correct answer is D, the thyrocervical trunk. This artery generally gives rise to the inferior thyroid artery. The thyrocervical trunk is a branch of the subclavian artery, supplying blood to the thyroid gland. The other choices are incorrect because the arch of aorta does not give rise to the inferior thyroid artery, the brachiocephalic artery does not directly supply the thyroid gland, and the external carotid artery does not typically provide blood to the thyroid gland. Therefore, the thyrocervical trunk is the most likely source for the inferior thyroid artery.

Correct Answer: b

Rationale: The correct answer is B because smooth muscle does not utilize troponin to help initiate muscle contraction. Instead, smooth muscle contraction is regulated by calcium-calmodulin complex. A: True - Smooth muscle usually forms 2 layers at right angles to each other. C: True - Smooth muscle contains no striations. D: False - Action potentials in smooth muscle travel slowly via gap junctions, not tight junctions.

Correct Answer: B

Rationale: The correct answer is B because the adenohypophysis refers specifically to the anterior pituitary gland, which secretes various hormones like growth hormone, prolactin, and thyroid-stimulating hormone. Choice A is incorrect because ADH and oxytocin are actually secreted by the neurohypophysis (posterior pituitary). Choice C is incorrect because releasing hormones are secreted by the hypothalamus, not the adenohypophysis. Choice D is incorrect because glucocorticoids, mineralocorticoids, and androgens are actually secreted by the adrenal cortex, not the anterior pituitary gland.