Nokea
The most appropriate drug for treating myasthenia gravis is:
- A. Neostigmine
- B. Pilocarpine
- C. Succinylcholine
- D. Tubocurarine
Correct Answer: A
Rationale: Neostigmine is the correct choice for treating myasthenia gravis as it is an acetylcholinesterase inhibitor that increases acetylcholine levels, improving muscle strength. Pilocarpine is a muscarinic agonist used for glaucoma. Succinylcholine is a depolarizing neuromuscular blocker used for intubation. Tubocurarine is a non-depolarizing neuromuscular blocker.
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All of the following are hormones of the anterior pituitary except:
- A. Growth hormone
- B. Follicle stimulating hormone
- C. Parthormone
- D. Thyroid stimulating hormone
Correct Answer: C
Rationale: The correct answer is C: Parthormone. The anterior pituitary gland secretes hormones such as Growth hormone, Follicle stimulating hormone, and Thyroid stimulating hormone, but not Parthormone. Parthormone is actually produced by the parathyroid glands, not the anterior pituitary gland. Parathormone plays a key role in regulating calcium levels in the blood. Therefore, choice C is incorrect as it does not belong to the hormones secreted by the anterior pituitary gland.
____________ is a steroid hormone.
- A. Vitamin D
- B. Epinephrine
- C. Insulin
- D. all of these
Correct Answer: A
Rationale: Vitamin D is the correct answer as it is a steroid hormone synthesized from cholesterol. Steroid hormones are derived from cholesterol and have a similar chemical structure. Epinephrine and Insulin are not steroid hormones. Epinephrine is a catecholamine produced by the adrenal glands, and Insulin is a peptide hormone produced by the pancreas. Choice D is incorrect as not all options listed are steroid hormones.
What medication is used with thyrotoxicosis to block the effects of the sympathetic nervous stimulation of the thyroid hormones?
- A. Potassium iodide
- B. Propylthiouracil (PTU)
- C. Atenolol (Tenormin)
- D. Radioactive iodine (RAI)
Correct Answer: C
Rationale: Atenolol is a beta-blocker that helps control the sympathetic nervous system effects of thyrotoxicosis, such as tachycardia and hypertension.
Which of the following is not a parasympatholytic drug:
- A. Atropine
- B. Propantheline
- C. Pirenzepine
- D. Edrophonium
Correct Answer: D
Rationale: The correct answer is D, Edrophonium, because it is not a parasympatholytic drug but rather a parasympathomimetic drug used for diagnosing myasthenia gravis. Atropine (A), Propantheline (B), and Pirenzepine (C) are all parasympatholytic drugs that inhibit the parasympathetic nervous system by blocking acetylcholine receptors. Atropine is a nonselective muscarinic receptor antagonist, Propantheline is an antimuscarinic drug used to treat gastrointestinal disorders, and Pirenzepine is a selective M1 receptor antagonist used to reduce gastric acid secretion. Therefore, D is the correct choice as it does not belong to the category of parasympatholytic drugs.
There are two simple ways to lower blood pressure: (1) reduce the cardiac contractility, and (2) inhibit sympathetic-mediated vasoconstriction. Which one of the following drugs can lower blood pressure by both mechanisms?
- A. Albuterol
- B. Atropine
- C. Labetalol
- D. Isoproterenol
Correct Answer: C
Rationale: Rationale: Labetalol is a non-selective beta-blocker that reduces cardiac contractility by blocking beta-1 receptors and inhibits sympathetic-mediated vasoconstriction by blocking alpha-1 receptors. Albuterol (A) is a beta-2 agonist, which increases cardiac contractility. Atropine (B) is a muscarinic antagonist, which increases heart rate and does not affect vasoconstriction. Isoproterenol (D) is a non-selective beta agonist, which increases cardiac contractility and vasodilation. Thus, C (Labetalol) is the only drug that can lower blood pressure by both mechanisms.