Antidiuretic hormone (ADH) and oxytocin:

Correct Answer: A

Rationale: Step-by-step rationale for choice A being correct: 1. ADH and oxytocin are peptide hormones. 2. They are synthesized in the hypothalamus. 3. They are transported and stored in the neurohypophysis. 4. Upon stimulation, they are released from the neurohypophysis. 5. Therefore, both ADH and oxytocin are indeed secreted by the neurohypophysis. Summary of why other choices are incorrect: B: ADH and oxytocin are not mineralocorticoids; they regulate water balance and uterine contractions, respectively. C: Islets of Langerhans secrete insulin and glucagon, not ADH or oxytocin. D: ADH promotes water reabsorption in the kidneys, opposite to excreting Na+ and water.

Correct Answer: B

Rationale: The correct answer is B: stimulates osteoclastic activity. Parathyroid hormone (PTH) acts on bones to stimulate osteoclasts, which are responsible for breaking down bone tissue to release calcium into the bloodstream. This process helps increase blood calcium levels. Choices A, C, and D are incorrect because PTH actually increases plasma calcium levels, is not an iodine-containing hormone, and does not stimulate osteoblastic activity.

Correct Answer: C

Rationale: Ketoacidosis is most related to excess fatty acid catabolism. During this process, the body breaks down fatty acids into ketones, leading to an accumulation of ketones in the blood and causing metabolic acidosis. Adrenocortical insufficiency (A) is related to cortisol deficiency, not ketoacidosis. Cushing syndrome (B) is associated with excess cortisol production, not ketoacidosis. Hyperglycemia (D) is high blood sugar levels and is not directly related to the mechanism of ketoacidosis.

Correct Answer: D

Rationale: Step-by-step rationale: 1. The anterior pituitary gland is connected to the hypothalamus by the portal capillaries. 2. This connection allows for the transport of releasing hormones from the hypothalamus to the anterior pituitary. 3. Releasing hormones stimulate the anterior pituitary to release specific hormones. 4. This communication pathway is essential for regulating hormone production and maintaining homeostasis. Summary of other choices: A: Incorrect. The neurohypophysis refers to the posterior pituitary, not the anterior pituitary. B: Incorrect. ADH and oxytocin are released from the posterior pituitary, not the anterior pituitary. C: Incorrect. Releasing hormones are produced by the hypothalamus, not the anterior pituitary.

Correct Answer: C

Rationale: The correct answer is C: Stimulating hepatic gluconeogenesis. Insulin's primary function is to lower blood glucose levels by promoting glucose uptake in cells and inhibiting gluconeogenesis in the liver. Choice A is correct as insulin helps lower blood glucose levels. Choice B is correct as insulin promotes protein synthesis. Choice D is correct as insulin promotes fatty acid synthesis to store excess glucose as fat. Therefore, choice C is incorrect as insulin actually inhibits hepatic gluconeogenesis rather than stimulating it.