Which cardiac structure is responsible for the heart's pumping action?

Question

Quizplus · Accepted Answer

The myocardium is the thick muscular middle layer that is responsible for the pumping action of the heart. The pericardium is the tough, double-walled, fibrous sac that protects the heart. The epicardium is the thin outermost muscle layer that covers the heart and extends onto the great vessels. The endocardium is the innermost layer that lines the chambers of the heart and covers heart valves. The atria are small, thin-walled structures that act primarily as reservoirs for the blood returning to the heart from the veins throughout the body.

Which Cardiac Structure Is Responsible for the Heart's Pumping Action