Which of the following is true of the conduction system of the heart?

Correct Answer: A

Rationale: The heart's conduction system (e.g., SA node, AV node) is composed of specialized cardiac muscle cells, not nervous tissue, and it generates beats autonomously without requiring external nervous stimuli.

Correct Answer: B

Rationale: The base of the heart lies at the level of the T5-T7 vertebrae, formed primarily by the atria, as it sits on the diaphragm.

Correct Answer: A

Rationale: Vasa vasorum supply the outer layers of large vessels, located in the tunica adventitia and outer tunica media.

Correct Answer: C

Rationale: Tricuspid valve stenosis produces a diastolic murmur due to obstructed flow during ventricular filling.

Correct Answer: A

Rationale: The SA node has a slow depolarizing phase due to slow calcium influx, unlike the rapid sodium-driven depolarization elsewhere.