Nokea
A young man presents with a blood pressure of 175/110 mm Hg. He is found to have a high circulating aldosterone but a low circulating cortisol. Glucocorticoid treatment lowers his circulating aldosterone and lowers his blood pressure to 140/85 mm Hg. He probably has an abnormal
- A. 17α-hydroxylase
- B. 21β-hydroxylase
- C. 3β-hydroxysteroid dehydrogenase
- D. aldosterone synthase
Correct Answer: A
Rationale: The correct answer is A: 17α-hydroxylase. In this scenario, the patient presents with hypertension, high aldosterone, and low cortisol levels. This pattern suggests a defect in the enzyme 17α-hydroxylase, which is responsible for both cortisol and aldosterone synthesis. Glucocorticoid treatment lowers aldosterone levels and subsequently normalizes blood pressure. The other choices (B: 21β-hydroxylase, C: 3β-hydroxysteroid dehydrogenase, D: aldosterone synthase) are not implicated in this specific presentation and do not align with the observed hormone levels and response to glucocorticoid therapy.
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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.
A patient with mild iatrogenic Cushing syndrome is on an alternate-day regimen of corticosteroid therapy. What does the nurse explain to the patient about this regimen?
- A. It maintains normal adrenal hormone balance.
- B. It prevents ACTH release from the pituitary gland.
- C. It minimizes hypothalamic-pituitary-adrenal suppression.
- D. It provides a more effective therapeutic effect of the drug.
Correct Answer: C
Rationale: Alternate-day corticosteroid therapy minimizes hypothalamic-pituitary-adrenal axis suppression, which helps prevent long-term adrenal insufficiency.
Epinephrine and norepinephrine from the adrenal medulla will produce the same results as the _____ nervous system.
- A. sympathetic
- B. parasympathetic
- C. somatic
- D. central
Correct Answer: A
Rationale: The correct answer is A: sympathetic. Epinephrine and norepinephrine are neurotransmitters released by the sympathetic nervous system. They activate the fight-or-flight response, increasing heart rate, dilating airways, and redirecting blood flow to muscles. The sympathetic nervous system prepares the body for action in response to stress or danger. Choices B, C, and D are incorrect because parasympathetic regulates rest and digest functions, somatic controls voluntary movements, and central refers to the brain and spinal cord, not a division of the autonomic nervous system like sympathetic.
With respect to calcium metabolism / bone formation:
- A. osteoclasts secrete alkaline phosphatase
- B. osteoblasts are haemopoietic derivatives of monocyte lineage
- C. 1,25(OH)2 ???D3 and PTH stimulate both osteoblasts and osteoclasts
- D. oestrogens are thought to be protective of osteoporosis as their main effect is osteoblasts stimulation
Correct Answer: C
Rationale: Rationale for Correct Answer (C):
1,25(OH)2 D3 and PTH stimulate both osteoblasts and osteoclasts. 1,25(OH)2 D3 enhances calcium absorption in the gut, promotes bone resorption, and stimulates osteoclast activity. PTH increases calcium levels in the blood by enhancing calcium reabsorption in the kidney and stimulating osteoclast activity. Both hormones indirectly stimulate osteoblasts by increasing calcium availability for bone formation.
Summary of Incorrect Choices:
A: Osteoclasts actually secrete acid, not alkaline phosphatase.
B: Osteoblasts are derived from mesenchymal stem cells, not monocytes.
D: Estrogens have a dual effect, inhibiting bone resorption by osteoclasts and stimulating bone formation by osteoblasts; their main effect is inhibiting osteoclast activity, not solely stimulating osteoblasts.
Drug X causes an increase in blood pressure and a decrease in heart rate when administered to a patient intravenously. If an antagonist at ganglionic nicotinic receptors is administered first, drug X causes an increase in blood pressure and an increase in heart rate. Drug X most likely is
- A. Propranolol
- B. Norepinephrine
- C. Isoproterenol
- D. Terbutaline
Correct Answer: B
Rationale: The correct answer is B: Norepinephrine. When an antagonist at ganglionic nicotinic receptors is administered, it blocks the inhibitory effect on sympathetic tone. Since norepinephrine is a sympathetic neurotransmitter that increases blood pressure and heart rate, it is likely that Drug X is norepinephrine. Propranolol (A) is a beta-blocker that decreases heart rate, Isoproterenol (C) is a beta-agonist that increases heart rate, and Terbutaline (D) is a beta-agonist that also increases heart rate. These choices do not align with the observed effects of Drug X when the ganglionic nicotinic receptor antagonist is administered.