The hypophyseal portal system transports releasing and inhibiting hormones from the hypothalamus to the __________.

Correct Answer: C

Rationale: The correct answer is C, the anterior pituitary gland. The hypophyseal portal system is a network of blood vessels that connects the hypothalamus to the anterior pituitary gland. This system allows the hypothalamus to release hormones that regulate the secretion of hormones from the anterior pituitary gland. The releasing and inhibiting hormones travel through this portal system directly to the anterior pituitary gland to exert their effects. Choices A, B, and D are incorrect because the hypophyseal portal system specifically targets the anterior pituitary gland, not the parathyroid glands, thyroid gland, or adrenal glands.

Correct Answer: D

Rationale: The correct answer is D: Splenic vein. The splenic vein lies posterior to the body of the pancreas. Step 1: Locate the pancreas in the abdominal cavity. Step 2: Identify the structures behind the body of the pancreas. Step 3: The splenic vein runs posterior to the body of the pancreas, making it the correct answer. Other choices are incorrect because A: IVC is located more inferiorly, B: Portal vein is located more superiorly, and C: Common bile duct is located more anteriorly to the body of the pancreas.

Correct Answer: a

Rationale: The correct answer is A: Calcitonin-parathyroid hormone. 1. Calcitonin lowers blood calcium levels by inhibiting bone breakdown, while parathyroid hormone raises blood calcium levels by stimulating bone breakdown. 2. This hormone pair directly opposes each other in regulating blood calcium levels. 3. Choices B, C, and D do not involve hormones with antagonistic effects on the same physiological process.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C is correct: 1. The adrenal medulla is part of the adrenal glands. 2. It secretes adrenaline and noradrenaline during the fight-or-flight response. 3. These hormones increase heart rate, blood flow to muscles, and provide energy for emergencies. 4. This physiological response helps the body deal with stressful situations. 5. Choices A, B, and D are incorrect because the adrenal medulla is not primarily controlled by ACTH, does not secrete steroids, and does not secrete iodine-containing hormones.

Correct Answer: B

Rationale: The correct answer is B: Graves' disease. Graves' disease is an autoimmune disorder that leads to overproduction of thyroid hormones, causing hyperthyroidism. This is characterized by symptoms such as weight loss, increased heart rate, and anxiety. Cushing syndrome (A) is caused by excess cortisol, not thyroid hormones. Addison's disease (C) is a condition where the adrenal glands do not produce enough hormones. ADH hypersecretion (D) refers to excessive production of antidiuretic hormone, not thyroid hormones. Therefore, the correct answer is Graves' disease due to its direct association with hyperthyroidism.