Nokea
A 38-year-old man with galactorrhea is treated with bromocriptine, which eliminates the galactorrhea. The basis for the therapeutic action of bromocriptine is that it
- A. antagonizes the action of prolactin on the breast
- B. enhances the action of prolactin on the breast
- C. inhibits prolactin release from the anterior pituitary
- D. inhibits prolactin release from the hypothalamus
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.
You may also like to solve these questions
Nicotinic receptors are blocked by which of the following:
- A. Propranolol
- B. Trimetaphan
- C. Prazosin
- D. Pilocarpine
Correct Answer: B
Rationale: The correct answer is B: Trimetaphan. Nicotinic receptors are blocked by non-depolarizing neuromuscular blockers like Trimetaphan. Propranolol (A) is a beta-blocker, Prazosin (C) is an alpha-1 blocker, and Pilocarpine (D) is a muscarinic agonist, none of which block nicotinic receptors. Therefore, Trimetaphan (B) is the only choice that directly blocks nicotinic receptors.
What is a cause of primary hypothyroidism in adults?
- A. Malignant or benign thyroid nodules
- B. Surgical removal or failure of the pituitary gland
- C. Surgical removal or radiation of the thyroid gland
- D. Autoimmune-induced atrophy of the thyroid gland
Correct Answer: D
Rationale: Primary hypothyroidism in adults is commonly caused by autoimmune diseases such as Hashimoto's thyroiditis, which leads to thyroid tissue destruction.
A benign tumor of the adrenal medulla:
- A. causes life-threatening low blood pressure.
- B. is called a pheochromocytoma.
- C. causes Addison’s disease.
- D. causes excess secretion of cortisol.
Correct Answer: B
Rationale: The correct answer is B: A benign tumor of the adrenal medulla is called a pheochromocytoma. Pheochromocytomas are tumors that arise from the adrenal medulla, leading to overproduction of catecholamines like adrenaline and noradrenaline. This excess secretion can result in symptoms such as high blood pressure, palpitations, and sweating. Choices A and C are incorrect because a benign tumor of the adrenal medulla typically causes high blood pressure, not low blood pressure or Addison's disease. Choice D is incorrect because excess cortisol secretion is associated with conditions like Cushing's syndrome, not pheochromocytoma.
A 32-year-old woman presents with a blood pressure of 155/96 mm Hg. In response to questioning, she admits that she loves licorice and eats some at least three times a week. She probably has a low level of
- A. type 2 11β-hydroxysteroid dehydrogenase activity
- B. ACTH
- C. 11β-hydroxylase activity
- D. glucocorticoid transferase
Correct Answer: A
Rationale: The correct answer is A: type 2 11β-hydroxysteroid dehydrogenase activity. Licorice contains glycyrrhizin, which inhibits this enzyme, leading to increased levels of cortisol and mineralocorticoids. This explains the elevated blood pressure in the patient. Choice B, ACTH, is incorrect because licorice consumption does not directly affect ACTH levels. Choice C, 11β-hydroxylase activity, is incorrect as licorice does not impact this enzyme directly. Choice D, glucocorticoid transferase, is also incorrect as licorice does not affect this enzyme's activity.
The endocrine system and the _____ system are both intimately involved in maintaining homeostasis.
- A. cardiovascular
- B. digestive
- C. nervous
- D. respiratory
Correct Answer: C
Rationale: The correct answer is C: nervous. The endocrine system and the nervous system work together to regulate various bodily functions and maintain homeostasis. The endocrine system releases hormones that control metabolism, growth, and reproduction, while the nervous system sends electrical signals to coordinate body movements and responses. Both systems communicate and coordinate with each other to ensure the body functions properly. Choices A, B, and D are incorrect because although they are important systems in the body, they do not play as direct a role in maintaining homeostasis as the nervous system does.