A patient presents with a bump on his neck. Upon taking a tissue sample, there appears to be parafollicular cells. The tumor is also associated with MEN II, although most of the time it is sporadic. What is the best way to moniter treatment?

Correct Answer: D

Rationale: Rationale: The parafollicular cells in the tissue sample indicate a tumor of the thyroid gland, likely medullary thyroid carcinoma (MTC) associated with Multiple Endocrine Neoplasia Type II (MEN II). MTC primarily secretes calcitonin. Monitoring Calcitonin levels is crucial for assessing disease progression and treatment response in MTC. Measuring Thyroid Hormone Levels (A) would not be specific for MTC. Iodine Levels (B) are not relevant in this context. TSH Levels (C) reflect pituitary feedback and are not specific to MTC. Therefore, the best way to monitor treatment in this case is to measure Calcitonin Levels (D).

Correct Answer: B

Rationale: The correct answer is B: testes. Androgens, such as testosterone, are male sex hormones primarily produced by the testes. The testes contain specialized cells called Leydig cells that secrete androgens. Ovaries (A) produce female sex hormones like estrogen and progesterone. The hypothalamus (C) regulates hormone production through the pituitary gland but does not directly produce androgens. Islets of Langerhans (D) are clusters of cells in the pancreas responsible for producing insulin and glucagon, not androgens.

Correct Answer: D

Rationale: The correct answer is D: thyroid hormone. Thyroid hormone plays a crucial role in regulating the rate of metabolism in all body cells by influencing the production of enzymes involved in energy production. It increases the body's metabolic rate, affecting processes such as heart rate, temperature regulation, and energy expenditure. Parathyroid hormone (A) regulates calcium levels, aldosterone (B) regulates electrolyte balance, and calcitonin (C) regulates calcium metabolism, but they do not directly influence overall metabolism rate in all body cells. Thyroid hormone is the primary hormone responsible for controlling metabolism throughout the body.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Bromocriptine is a dopamine agonist. 2. Dopamine inhibits prolactin release from the anterior pituitary. 3. Galactorrhea is often caused by excess prolactin. 4. By inhibiting prolactin release, bromocriptine reduces prolactin levels and eliminates galactorrhea. Summary: A: Incorrect - Bromocriptine does not antagonize prolactin action. B: Incorrect - Bromocriptine does not enhance prolactin action. D: Incorrect - Prolactin is not released from the hypothalamus.

Correct Answer: A

Rationale: The correct answer is A because oxytocin release is an example of a positive feedback control mechanism. When oxytocin is released during childbirth, it stimulates contractions, which in turn lead to more oxytocin release, creating a positive feedback loop. This helps in the progression of labor. Choice B is incorrect because oxytocin is a neurohypophyseal hormone, not an adenohypophyseal secretion. Choice C is incorrect as oxytocin's main effects are related to labor, delivery, and lactation, not menstruation. Choice D is incorrect because oxytocin primarily controls uterine contractions during labor and milk ejection during breastfeeding, not milk production itself.