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What kind of cells make up the sinoatrial node?
AEndothelial pacemaker lining cells
BSpecialized myocardial conducting cells
CModified smooth muscle fiber cells
DAutonomic ganglion nerve cell bodies
Answer & Solution
Correct answer: B. Specialized myocardial conducting cells
1. The SA node is cardiac tissue, not nervous tissue.
2. It is a specialized clump of myocardial conducting cells.
3. Neurons modulate its rate but do not compose it, which is the trap in the last option.
_Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 19 "The Cardiovascular System: The Heart", section 19.2 Cardiac Muscle and Electrical Activity_
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