Erythrocyte production:

Correct Answer: B

Rationale: Erythropoiesis requires intrinsic factor from gastric juice for B₁₂ absorption; its loss (e.g., pernicious anemia) reduces RBC production. Estrogen doesn’t directly stimulate it, the spleen isn’t a primary site in adults (bone marrow is), and amino acids aren’t a key trigger.

Correct Answer: A

Rationale: The absolute refractory period, when the heart is fully relaxed (early diastole) and unresponsive to stimuli, lasts ~0.2 seconds in a typical 0.8-second cardiac cycle (at 75 bpm). It aligns with ventricular relaxation before atrial systole. Other durations are too short or long for this phase.

Correct Answer: C

Rationale: Warfarin blocks vitamin K-dependent clotting factors. Saying clients can’t eat green, leafy vegetables (C) is incorrect; they should maintain consistent vitamin K intake, not avoid it. Asking about supplements (A), monitoring vitamin K (B), and regular blood tests (D) are accurate. (Source: Document, p. 13-14)

Correct Answer: B

Rationale: The left ventricle (B) has the thickest wall (~10-15 mm) to pump blood against high systemic resistance (~120 mmHg). The right ventricle (D) is thinner (~4-5 mm) for pulmonary circulation (~25 mmHg), and atria (A, C) are thinnest as they only pump to ventricles.

Correct Answer: A

Rationale: A heart murmur is caused by turbulent blood flow from leaky (incompetent) or stenotic valves (A). Cardiac arrest (B) stops the heart, normal valve action (C) doesn’t cause murmurs, and extra beats (D) are arrhythmias, not murmurs.