Enlargement of the thyroid gland:

Correct Answer: A

Rationale: Step-by-step rationale for why choice A is correct: 1. Enlargement of the thyroid gland is known as a goiter. 2. A goiter can result from various conditions like iodine deficiency or thyroid disorders. 3. It is a common sign of thyroid dysfunction. 4. Goiter may or may not cause symptoms depending on the underlying cause. 5. Therefore, choice A is the correct answer. Summary: - Choice B (Addisonian crisis) is incorrect as it is associated with adrenal insufficiency, not thyroid enlargement. - Choice C (cushingoid appearance) is incorrect as it is related to excess cortisol production, not thyroid enlargement. - Choice D (hypocalcemic tetany) is incorrect as it is due to low calcium levels, not thyroid enlargement.

Correct Answer: D

Rationale: The correct answer is D: hyperglycemia. Hyperglycemia refers to high blood sugar levels, a hallmark of diabetes mellitus. Insulin therapy is commonly prescribed to individuals with diabetes to help regulate their blood sugar levels. Myxedema (choice A) is associated with hypothyroidism, Graves' disease (choice B) is an autoimmune disorder affecting the thyroid, and diabetes insipidus (choice C) involves the kidneys and has no direct relation to insulin therapy for diabetes. Therefore, hyperglycemia is the most appropriate condition for receiving insulin therapy.

Correct Answer: C

Rationale: The correct answer is C because epinephrine is not a steroid hormone. Steroids are synthesized from cholesterol and have a specific chemical structure, while epinephrine is a catecholamine. Cortisol, aldosterone, and testosterone are examples of steroid hormones, but epinephrine belongs to the class of catecholamines. Therefore, C is incorrect. A, B, and D are correct as they accurately list hormones produced by the anterior pituitary gland, posterior pituitary gland, and gonads respectively.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Prolactin is also called lactogenic hormone, as it promotes milk production in the mammary glands. 2. Secreted by the anterior pituitary gland, not the posterior pituitary gland. 3. Milk let-down reflex is primarily controlled by oxytocin, not prolactin. 4. Prolactin does not stimulate the neurohypophysis (posterior pituitary) to synthesize oxytocin. Summary: Choice B is correct because it accurately describes the function of prolactin in promoting lactation. Choices A, C, and D are incorrect due to inaccuracies in the functions and secretion of prolactin.

Correct Answer: C

Rationale: The correct answer is C: PTH. Parathyroid hormone (PTH) stimulates osteoclastic activity, leading to bone resorption. PTH plays a crucial role in regulating calcium levels in the blood. When calcium levels are low, PTH is released to stimulate the release of calcium from bones through osteoclast activity. A: Calcitonin actually inhibits osteoclastic activity, promoting bone formation. B: Androgen is a male sex hormone and does not directly influence bone resorption. D: Thyroxine is a thyroid hormone that regulates metabolism and does not directly affect bone resorption.