Which of the following best describes the function of insulin?

Correct Answer: A

Rationale: The correct answer is A: Lowers blood glucose levels. Insulin is a hormone produced by the pancreas that helps regulate blood glucose levels by promoting the uptake of glucose into cells for energy storage. This process reduces the concentration of glucose in the bloodstream. Choices B, C, and D are incorrect because insulin does not stimulate cells to make glucose (B), deficiency does not cause diabetes insipidus (C), and it does not directly affect blood volume (D).

Correct Answer: B

Rationale: Thyroxine is also known as T4, a thyroid hormone produced by the thyroid gland. It plays a crucial role in regulating metabolism. TSH (Thyroid Stimulating Hormone) is a hormone produced by the pituitary gland to stimulate thyroid hormone production, not thyroxine itself. Choice C is incorrect because thyroxine exerts negative feedback on TSH, not T3. Choice D is incorrect as thyroxine actually increases basal metabolic rate. Thus, the correct answer is B as thyroxine is indeed T4.

Correct Answer: D

Rationale: The correct answer is D. The adrenal cortex secretes cortisol, the pancreas secretes insulin, and the adenohypophysis secretes growth hormone. Cortisol helps regulate metabolism, insulin controls blood sugar levels, and growth hormone stimulates growth. Choice A is incorrect because ADH is not secreted by the adrenal cortex, and aldosterone is not secreted by the pancreas or adenohypophysis. Choice B is incorrect because epinephrine is not secreted by the adrenal cortex, and ACTH is not secreted by the pancreas or adenohypophysis. Choice C is incorrect because androgen is not secreted by the pancreas or adenohypophysis, and ADH is not secreted by the adrenal cortex.

Correct Answer: D

Rationale: The correct answer is D: Secrete FSH. The hypothalamus produces releasing and inhibiting hormones that regulate the pituitary gland's secretion of hormones such as FSH. The hypothalamus itself does not secrete FSH. A, B, and C are functions of the hypothalamus as it is involved in regulating heart rate, temperature control, and water balance through various hormonal and neural pathways.

Correct Answer: C

Rationale: The correct answer is C: Gonadal. The secretions from gonads (testes in males, ovaries in females) differ between males and females due to the production of sex hormones (testosterone in males, estrogen and progesterone in females). Adrenal glands (A) secrete similar hormones in both genders. Parathyroid (B) and Pancreas (D) do not secrete hormones that differ based on gender.