Which of the following vitamin or mineral supplements may by teratogenic if a pregnant woman takes more than the recommended amount?
- A. Iron
- B. Vitamin A
- C. Vitamin B6
- D. Vitamin C
Correct Answer: B
Rationale: Excess vitamin A (retinol) is teratogenic, potentially causing congenital malformations.
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Jacob has hypertension, for which a calcium channel blocker has been prescribed. This drug helps control blood pressure because it:
- A. Decreases the amount of calcium inside the cell
- B. Reduces stroke volume
- C. Increases the activity of the Na+/K+/ATPase pump indirectly
- D. Decreases heart rate
Correct Answer: A
Rationale: Calcium channel blockers reduce intracellular calcium, relaxing vascular smooth muscle.
In which type of cell are ligand-gated ion channels most commonly found?
- A. Cells that are terminally differentiated
- B. Cells that produce large proteins
- C. Cells that need to respond quickly to external stimuli
- D. Cells that respond to mechanic forces
Correct Answer: C
Rationale: Ligand-gated ion channels enable rapid responses to stimuli, common in excitable cells like neurons and muscle cells.
A patient with Cushing's syndrome is being treated by X-irradiation of the pituitary. It may take several months of treatment for adequate symptomatic and metabolic improvement. Until that time, which of the following might be administered adjunctively to suppress glucocorticoid synthesis?
- A. Cimetidine
- B. Cortisol (massive doses)
- C. Fludrocortisone
- D. Ketoconazole
Correct Answer: D
Rationale: Ketoconazole inhibits adrenal steroidogenesis, reducing glucocorticoid levels in Cushing's syndrome.
Who defines the standards of care for the practice of nursing? (Select one that does not apply.)
- A. State boards of nursing
- B. Hospital policy and procedures
- C. Federal laws regulating health care facilities
- D. The Joint Commission
Correct Answer: B
Rationale: Standards of care are defined by state boards of nursing, federal laws regulating health care facilities, The Joint Commission, and professional nursing associations such as the American Nurses Association. Individual hospital policies and procedures incorporate federal and state guidelines into their respective policies and procedures and are often more stringent than state and federal regulations.
Low doses of aspirin prolong bleeding time by selectively inhibiting synthesis of the following mediator in the platelets:
- A. Thromboxane Aâ‚‚
- B. 5-Hydroxytryptamine
- C. Platelet activating factor
- D. Prostacyclin
Correct Answer: A
Rationale: Low-dose aspirin irreversibly inhibits COX-1 in platelets, reducing thromboxane Aâ‚‚ production, which promotes platelet aggregation, thus prolonging bleeding time.