Nokea
Parasympathomimetic drugs are drugs that:
- A. Inhibit muscarinic receptors
- B. Inhibit release of acetylcholine
- C. Inhibit adrenergic receptors
- D. Stimulate muscarinic receptors
Correct Answer: D
Rationale: The correct answer is D: Stimulate muscarinic receptors. Parasympathomimetic drugs mimic the actions of the parasympathetic nervous system, which primarily uses acetylcholine on muscarinic receptors to produce its effects. By stimulating muscarinic receptors, these drugs enhance parasympathetic activity.
A, B, and C are incorrect:
A: Inhibiting muscarinic receptors would have the opposite effect of parasympathomimetic drugs.
B: Inhibiting the release of acetylcholine would also reduce parasympathetic activity.
C: Inhibiting adrenergic receptors pertains to the sympathetic nervous system, not the parasympathetic system targeted by parasympathomimetic drugs.
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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.
As plasma levels of calcium decrease:
- A. insulin is secreted.
- B. the parathyroid glands secrete an osteoclastic hormone.
- C. the kidneys excrete calcium and phosphorus.
- D. calcitonin is secreted.
Correct Answer: B
Rationale: The correct answer is B because as plasma levels of calcium decrease, the parathyroid glands secrete an osteoclastic hormone called parathyroid hormone (PTH). PTH acts to increase calcium levels by stimulating the release of calcium from bones via osteoclasts. Insulin secretion (choice A) is not directly related to calcium levels. The kidneys excreting calcium and phosphorus (choice C) would further decrease calcium levels. Calcitonin (choice D) actually decreases blood calcium levels by inhibiting bone breakdown, so it is not secreted when calcium levels decrease.
Which hormone is responsible for milk production in the mammary glands?
- A. somatotropin
- B. prolactin
- C. luteinizing hormone
- D. follicle-stimulating hormone
Correct Answer: B
Rationale: Prolactin is the correct answer because it is the hormone responsible for milk production in the mammary glands. It is secreted by the pituitary gland in response to the suckling stimulus from the baby. Prolactin stimulates the alveoli in the mammary glands to produce milk. Somatotropin (A), luteinizing hormone (C), and follicle-stimulating hormone (D) do not play a direct role in milk production. Somatotropin is involved in growth, luteinizing hormone is involved in ovulation, and follicle-stimulating hormone is involved in the development of ovarian follicles.
Androgens are produced by the _______.
- A. ovaries.
- B. testes.
- C. hypothalamus.
- D. islets of Langerhans.
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.
The endocrine system works together with the ________ system to maintain the body’s equilibrium?
- A. digestive system
- B. nervous system
- C. respiratory system
- D. reproductive system
Correct Answer: B
Rationale: The correct answer is B: nervous system. The endocrine system and nervous system work together in maintaining the body's equilibrium through communication and regulation of bodily functions. The nervous system controls rapid responses, while the endocrine system regulates slower, long-term responses through hormones. The digestive system (A) primarily focuses on breaking down food and absorbing nutrients. The respiratory system (C) is responsible for gas exchange. The reproductive system (D) is involved in reproduction and hormone production, but not in maintaining the body's equilibrium.