Adrenaline is NOT given orally because:
- A. It is inactivated in the gut mucosa
- B. Local vasoconstriction inhibits absorption
- C. It is rapidly inactivated in circulation
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D: All of the above. Adrenaline is not given orally because: A) It is inactivated in the gut mucosa due to enzymatic breakdown, B) Local vasoconstriction inhibits absorption into the bloodstream, and C) It is rapidly inactivated in circulation by enzymes like catechol-O-methyltransferase and monoamine oxidase. Therefore, administering adrenaline orally would result in poor absorption and rapid degradation, making it ineffective.
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Which is INCORRECT regarding nerve supply to the gut?
- A. the blood vessels are known to have enteric, parasympathetic and sympathetic innervation
- B. the myenteric plexus lies between the longitudinal and circular muscle layers
- C. parasympathetic supply is via vagal and sacral nerve
- D. sympathetic supply is often inhibitory on cholinergic postganglionic fibres
Correct Answer: A
Rationale: The correct answer is A because blood vessels in the gut are primarily innervated by sympathetic and parasympathetic fibers, not by enteric nerves. Enteric nerves are confined to the gastrointestinal tract itself and are responsible for regulating gut motility, secretion, and blood flow. Sympathetic innervation typically causes vasoconstriction, while parasympathetic innervation promotes vasodilation. The myenteric plexus (Auerbach's plexus) lies between the longitudinal and circular muscle layers, regulating gut motility. Parasympathetic supply to the gut is mainly through the vagus nerve (cranial nerve X) and sacral nerves (pelvic splanchnic nerves). Sympathetic supply can either be inhibitory or excitatory, but generally, sympathetic fibers are inhibitory on cholinergic postganglionic fibers in the gut.
A 78-year-old male with Parkinson’s disease experiences worsening of his symptoms. He is already taking levodopa. Since the disease is characterized by degeneration of dopaminergic neurons, leading to the lack of inhibition of cholinergic neurons, the addition of which medication is likely to help alleviate the patient’s symptoms?
- A. Benztropine
- B. Reserpine
- C. Doxazosin
- D. Timolol
Correct Answer: A
Rationale: The correct answer is A: Benztropine. Benztropine is an anticholinergic medication that helps alleviate Parkinson's disease symptoms by blocking the excess activity of acetylcholine, which is increased due to the lack of dopaminergic inhibition. This leads to a rebalancing of neurotransmitters in the brain, improving motor symptoms.
Choice B: Reserpine depletes neurotransmitters including dopamine, worsening Parkinson's symptoms.
Choice C: Doxazosin is an alpha-blocker used for hypertension, not Parkinson's disease.
Choice D: Timolol is a beta-blocker used for glaucoma, not Parkinson's disease.
“Sugar, salt, and sex†is descriptive of
- A. ACTH, TSH, and somatotropic hormone.
- B. cortisol, aldosterone, and testosterone.
- C. epinephrine, norepinephrine, and estrogen.
- D. insulin, glucagon, and cortisol.
Correct Answer: B
Rationale: The correct answer is B: cortisol, aldosterone, and testosterone. "Sugar, salt, and sex" refers to hormones produced by the adrenal glands. Cortisol regulates sugar metabolism, aldosterone regulates salt balance, and testosterone is involved in sexual characteristics. A: ACTH, TSH, and somatotropic hormone are hormones produced by the pituitary gland. C: Epinephrine, norepinephrine, and estrogen are not directly related to the terms given. D: Insulin, glucagon, and cortisol are involved in glucose regulation, but do not match the specific terms provided.
Target cells respond to hormones because ____________.
- A. they sit next to the cell that makes the hormone
- B. they made the hormone they are responding to
- C. they have receptors for that hormone
- D. all cells in the body respond to all hormones
Correct Answer: C
Rationale: The correct answer is C because target cells respond to hormones by possessing specific receptors for that hormone. These receptors bind to the hormone, initiating a cellular response. Option A is incorrect as proximity to hormone-producing cells is not the reason for response. Option B is incorrect as target cells do not make the hormones they respond to. Option D is incorrect as not all cells respond to all hormones; only target cells with specific receptors do.
Which of the following is the most common adverse reaction during initial therapy with a thyroid replacement?
- A. Allergy
- B. Signs of hyperthyroidism
- C. Weight loss
- D. Bones become demineralized
Correct Answer: B
Rationale: Signs of hyperthyroidism are a common adverse reaction during initial therapy with thyroid replacement due to the body adjusting to the increased thyroid hormone levels.