Ketone bodies:

Correct Answer: C

Rationale: Ketone bodies form during glucose deficiency (e.g., fasting), are acids, but are metabolized by extrahepatic tissues, not easily in the liver.

Correct Answer: D

Rationale: Parathormone, or parathyroid hormone, is produced and secreted by the parathyroid glands. Low calcium levels will stimulate release of parathyroid hormone, which increases the plasma level of calcium. Parathormone acts on the renal tubules to increase the excretion of phosphorus in the urine and to stimulate the reabsorption of calcium. Parathormone also acts on bone, causing the release of calcium from the bone into the bloodstream.

Correct Answer: A

Rationale: Hyperplasia (increased cellular growth) is the usual cause of hypersecretion of an endocrine gland.

Correct Answer: C

Rationale: The actual structural unit that secretes insulin is the beta cell. Beta cells are found on the islets of Langerhans, which are in the pancreas.

Correct Answer: D

Rationale: The posterior pituitary (neurohypophysis) releases ADH and oxytocin, which are produced by the hypothalamus and stored in the posterior pituitary.