Nokea
A 33-year-old woman becomes poisoned after receiving an injection of concentrated botulinum toxin. Which of the following is the main neurochemical mechanism by which this Clostridium toxin causes its effects?
- A. Directly activates all muscarinic and nicotinic receptors
- B. Inhibits ACh release from all cholinergic nerves
- C. Prevents neuronal norepinephrine reuptake
- D. Releases norepinephrine via a nonexocytotic process
Correct Answer: B
Rationale: The correct answer is B: Inhibits ACh release from all cholinergic nerves. Botulinum toxin blocks the release of acetylcholine (ACh) from cholinergic nerve terminals, leading to muscle paralysis. This occurs through the cleavage of SNARE proteins, preventing vesicle fusion and neurotransmitter release. Choice A is incorrect because botulinum toxin does not directly activate receptors. Choice C is incorrect as botulinum toxin does not affect neuronal norepinephrine reuptake. Choice D is incorrect because botulinum toxin does not release norepinephrine via a nonexocytotic process.
You may also like to solve these questions
Which gland secretes two hormones, one that elevates blood glucose levels and another that decreases blood glucose levels?
- A. Pancreas
- B. Adenohypophysis
- C. Thyroid
- D. Adrenal cortex
Correct Answer: A
Rationale: The correct answer is A: Pancreas. The pancreas secretes insulin to decrease blood glucose levels and glucagon to elevate blood glucose levels. Insulin helps cells absorb glucose for energy, while glucagon triggers the release of stored glucose into the bloodstream. Adenohypophysis (B) secretes various hormones but not related to blood glucose regulation. Thyroid (C) secretes hormones that regulate metabolism, not directly impacting blood glucose levels. Adrenal cortex (D) secretes hormones like cortisol and aldosterone, which are not primarily involved in blood glucose regulation.
Which gland is responsible for the production of insulin?
- A. ovaries
- B. testes
- C. hypothalamus
- D. islets of Langerhans
Correct Answer: D
Rationale: The correct answer is D: islets of Langerhans. These clusters of cells within the pancreas are responsible for producing insulin. Insulin is a hormone that regulates blood sugar levels. The ovaries (A) and testes (B) are not responsible for insulin production. The hypothalamus (C) plays a role in regulating many bodily functions, but it is not directly involved in insulin production.
Antoinette has gone to her primary care provider for a routine physical. Some of her laboratory results indicated an endocrine disorder. In hyperparathyroidism which test results are typical?
- A. Decreased WBC and increased alkaline phosphatase.
- B. Increased calcium and decreased phosphate.
- C. Decreased PTH and increased magnesium.
- D. Increased PTH and decreased calcium.
Correct Answer: B
Rationale: In hyperparathyroidism, increased parathyroid hormone (PTH) leads to increased calcium levels and decreased phosphate levels in the blood.
A drug useful in the treatment of acute attack of migraine is:
- A. Sumatriptan
- B. Ergometrine
- C. Dihydroergometrine
- D. Propranolol
Correct Answer: A
Rationale: Sumatriptan is the correct answer for treating acute migraine attacks as it is a specific serotonin receptor agonist that helps constrict blood vessels in the brain. Ergometrine and dihydroergometrine are ergot alkaloids used for other conditions, not migraine. Propranolol is a beta-blocker used for migraine prevention, not acute attacks.
One of the two hormones made by the pituitary that help regulate reproductive cells is luteinizing hormone. The other hormone is .
- A. follicle-stimulating hormone
- B. epinephrine
- C. norepinephrine
- D. androgens
Correct Answer: A
Rationale: The correct answer is A: follicle-stimulating hormone (FSH). FSH is the other hormone made by the pituitary gland that helps regulate reproductive cells, along with luteinizing hormone (LH). FSH is responsible for stimulating the growth and maturation of ovarian follicles in females and spermatogenesis in males.
Explanation:
1. FSH is directly involved in the reproductive process by stimulating follicle development and sperm production.
2. Epinephrine and norepinephrine are not hormones produced by the pituitary gland and are involved in the stress response.
3. Androgens are male sex hormones produced primarily by the testes, not the pituitary gland.
In summary, FSH is the correct answer as it plays a crucial role in regulating reproductive cells, while the other choices are not involved in the reproductive system or are not produced by the pituitary gland.