Which layer of the heart allows it to act as a pump?
The heart wall has three walls : endocardium, myocardium and pericardium. The myocardium is the thickest of the three wall and it is composed of cardiac muscle cells. Cardiac muscle cells have a special property of involuntary rhythmical contraction.
This rhythmical contraction of the myocardium allows the heart to act as a pump.