The superior suprarenal artery arises from:
- A. Abdominal aorta
- B. Inferior phrenic artery
- C. Renal artery
- D. Superior mesenteric artery
Correct Answer: B
Rationale: The correct answer is B: Inferior phrenic artery. The superior suprarenal artery arises from the inferior phrenic artery, which supplies blood to the adrenal gland. The inferior phrenic artery originates from the abdominal aorta, near the celiac trunk. It is important to note that the adrenal glands receive blood supply from multiple sources, including the inferior phrenic artery. The other choices (A: Abdominal aorta, C: Renal artery, D: Superior mesenteric artery) do not directly supply blood to the adrenal glands, making them incorrect options.
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Which artery generally gives rise to inferior thyroid artery?
- A. Arch of aorta
- B. Brachiocephalic artery
- C. External carotid artery
- D. Thyrocervical trunk
Correct Answer: D
Rationale: The correct answer is D, the thyrocervical trunk. This artery generally gives rise to the inferior thyroid artery. The thyrocervical trunk is a branch of the subclavian artery, supplying blood to the thyroid gland. The other choices are incorrect because the arch of aorta does not give rise to the inferior thyroid artery, the brachiocephalic artery does not directly supply the thyroid gland, and the external carotid artery does not typically provide blood to the thyroid gland. Therefore, the thyrocervical trunk is the most likely source for the inferior thyroid artery.
Regarding parasympatholytics, the following statement is WRONG:
- A. Hyoscine is preferred over atropine in preanesthetic medication of thyrotoxic patients.
- B. Pirenzepine is preferred over propantheline in the treatment of intestinal colic.
- C. Ipratropium is better than atropine in the treatment of bronchial asthma
- D. Tropicamide is better than atropine in fundus examination
Correct Answer: B
Rationale: The correct answer is B. Pirenzepine is NOT preferred over propantheline in the treatment of intestinal colic because pirenzepine is a selective M1 receptor antagonist used for peptic ulcer disease, while propantheline is an anticholinergic used for GI spasms. Choice A is incorrect because atropine is preferred over hyoscine in thyrotoxic patients due to its faster onset. Choice C is incorrect because ipratropium is not necessarily better than atropine in bronchial asthma as they have different mechanisms of action. Choice D is incorrect because atropine is actually preferred over tropicamide for fundus examination due to its longer duration of action.
Nitroglycerin is a vasodilator used in the treatment of angina. A common side effect of its vasodilator activity is a reflex increase in heart rate, which is sometimes dangerous. Which drug could inhibit this reflex cardiac stimulation?
- A. Atropine
- B. Cocaine
- C. Phentolamine
- D. Propranolol
Correct Answer: D
Rationale: The correct answer is D: Propranolol. Propranolol is a beta-blocker that blocks the beta-adrenergic receptors in the heart, preventing the reflex increase in heart rate caused by nitroglycerin. This action helps to counteract the potentially dangerous side effect of increased heart rate.
A: Atropine is not the correct answer because it is an anticholinergic drug that increases heart rate, which would exacerbate the reflex cardiac stimulation caused by nitroglycerin.
B: Cocaine is a stimulant drug that can further increase heart rate and is not used to inhibit reflex cardiac stimulation.
C: Phentolamine is an alpha-blocker that primarily acts on alpha-adrenergic receptors and is not the preferred drug for inhibiting the reflex increase in heart rate caused by nitroglycerin.
Which is not a function of the hypothalamus?
- A. Affect heart rate
- B. Control temperature
- C. Affect water balance
- D. Secrete FSH
Correct Answer: D
Rationale: The correct answer is D: Secrete FSH. The hypothalamus produces releasing and inhibiting hormones that regulate the pituitary gland's secretion of hormones such as FSH. The hypothalamus itself does not secrete FSH. A, B, and C are functions of the hypothalamus as it is involved in regulating heart rate, temperature control, and water balance through various hormonal and neural pathways.
A patient presents with food poisoning that is attributed to botulism (Botulinum toxin poisoning). Which of the following is a correct characteristic, finding, or mechanism associated with this toxin?
- A. Complete failure of all cholinergic neurotransmission
- B. Favorable response to administration of pralidoxime
- C. Impairment of parasympathetic, but not sympathetic, nervous system activation
- D. Massive overstimulation of all structures having muscarinic cholinergic receptors
Correct Answer: A
Rationale: The correct answer is A: Complete failure of all cholinergic neurotransmission. Botulinum toxin inhibits acetylcholine release at neuromuscular junctions, leading to complete failure of all cholinergic neurotransmission. This results in flaccid paralysis and characteristic symptoms of botulism. Choice B is incorrect because pralidoxime is used to treat organophosphate poisoning, not botulism. Choice C is incorrect as botulinum toxin affects both parasympathetic and sympathetic nervous systems. Choice D is incorrect as botulinum toxin does not cause overstimulation but rather inhibits neurotransmission.