What is the origin of accessory pancreatic duct?

Correct Answer: B

Rationale: The correct answer is B: Proximal part of dorsal pancreatic bud. The accessory pancreatic duct originates from the dorsal pancreatic bud during embryonic development. This is because the dorsal pancreatic bud gives rise to the body and tail of the pancreas, which includes the accessory pancreatic duct. The proximal part of the dorsal pancreatic bud specifically gives rise to the proximal part of the accessory pancreatic duct. Choices A, C, and D are incorrect because they refer to the distal part of the dorsal pancreatic bud, the distal part of the ventral pancreatic bud, and the proximal part of the ventral pancreatic bud, respectively, which are not associated with the origin of the accessory pancreatic duct.

Correct Answer: A

Rationale: Step-by-step rationale: 1. The adrenal cortex is the outer layer of the adrenal gland that produces steroid hormones. 2. ACTH (adrenocorticotropic hormone) stimulates the adrenal cortex to secrete cortisol and aldosterone. 3. Therefore, the adrenal cortex is the target gland of ACTH, making choice A correct. Summary: A. Correct - The adrenal cortex is the target gland of ACTH. B. Incorrect - The adrenal medulla secretes catecholamines (e.g., adrenaline, noradrenaline). C. Incorrect - The sympathetic nervous system is responsible for the fight-or-flight response, not the adrenal cortex. D. Incorrect - ADH (antidiuretic hormone) and oxytocin are produced by the hypothalamus and released by the posterior pituitary gland, not the adrenal cortex.

Correct Answer: B

Rationale: The correct answer is B: Portal capillaries. The hypothalamus and adenohypophysis are connected by a system of blood vessels called the hypothalamic-pituitary portal system, which includes portal capillaries. These capillaries carry releasing and inhibiting hormones from the hypothalamus to the adenohypophysis to regulate the secretion of pituitary hormones. The other choices are incorrect because: A: Islets of Langerhans are clusters of cells in the pancreas involved in insulin and glucagon production, not connected to the hypothalamus or adenohypophysis. C: The corpus callosum is a structure that connects the two cerebral hemispheres and is not related to the hypothalamus or adenohypophysis. D: The medulla oblongata is part of the brainstem responsible for autonomic functions and is not involved in connecting the hypothalamus and adenohypophysis.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Hypocalcemic tetany is associated with low levels of calcium in the blood. 2. Parathyroid hormone (PTH) plays a crucial role in calcium regulation. 3. A deficiency of PTH can lead to decreased calcium levels, causing tetany. 4. Therefore, choice C is correct as hypocalcemic tetany may be caused by a deficiency of PTH. Summary: A: Incorrect. Hypocalcemic tetany leads to muscle spasms, not flaccid paralysis. B: Incorrect. Curare blockade affects neuromuscular transmission, not calcium levels. D: Incorrect. Insulin deficiency is associated with hyperglycemia, not hypocalcemia leading to tetany.

Correct Answer: C

Rationale: Rationale: 1. Myxedema is caused by hypothyroidism, which can be effectively treated with thyroxine. 2. Thyroxine is a synthetic form of thyroid hormone that helps restore thyroid hormone levels. 3. Myxedema symptoms such as fatigue, weight gain, and cold intolerance improve with thyroxine treatment. Summary of Incorrect Choices: A. Diabetes mellitus and hyperglycemia are not directly related to thyroid hormone levels. B. Hyperglycemia is not primarily treated with thyroxine. D. Graves' disease is a thyroid disorder characterized by hyperthyroidism, which requires different treatments than hypothyroidism.