Which of the following carry deoxygenated blood from the right atrium to the lungs?

Correct Answer: C

Rationale: The pulmonary arteries carry deoxygenated blood from the right ventricle (after passing through the right atrium) to the lungs for oxygenation. Pulmonary veins carry oxygenated blood back to the left atrium, the aorta carries oxygenated blood systemically, and the superior vena cava delivers deoxygenated blood to the right atrium.

Correct Answer: A

Rationale: Leukocytes and platelets form ~1% of blood volume; RBCs (formed elements) are ~45%, and plasma is ~55%. The combined fraction is small due to their low numbers relative to RBCs.

Correct Answer: D

Rationale: The second heart sound (S₂) results from semilunar valve closure (aortic and pulmonary) at the start of diastole and can split due to asynchronous closure (A and C are true). S₁ (AV valve closure) is longer and lower-pitched (~0.14s) than S₂ (~0.11s), making D incorrect as S₂ is shorter, not longer.

Correct Answer: D

Rationale: Retroperitoneal hemorrhage post-PCI requires notifying the provider and preparing for a CT scan or blood transfusion (D) to diagnose and treat bleeding, which can cause hypotension. Intubation (A) is unrelated, ambulation (B) worsens bleeding, and back pressure (C) is ineffective for internal hemorrhage. (Source: Document, p. 8-9)

Correct Answer: D

Rationale: The AV node delays the impulse (C, ~0.1s) to allow atrial contraction before ventricular systole and directs it to the ventricles via the bundle of His (A). It’s not the pacemaker (B, that’s the SA node), so E (A and C) is correct.