A client has a diagnosis of bacterial endocarditis (affecting the endocardium). The nurse knows that the client's infection is located in the:

Correct Answer: D

Rationale: The innermost lining of the heart is called the endocardium. The myocardium is the middle, muscle layer of heart tissue. The membrane that surrounds the heart is the pericardium. The mediastinum is the area of the thoracic cavity between the two lungs. (Source: Document, Pretest Answer 1, p. 76)

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: D

Rationale: Hemoglobin A (adult) has 2 α and 2 β polypeptide chains (globin) and 4 heme groups (iron-containing), allowing it to bind 4 oxygen molecules. ‘Globin molecules’ alone is vague and incorrect.

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)