Diagram to illustrate the action (pumping) of the heart. Labels: aur., auricle; vent., ventricle; v, veins; a, aorta; m, mitral valve; s, semilunar valves. In A, auricle contracting, ventricle dilated, mitral valve open, semilunar valves closed. In B, auricle dilated, ventricle contracting, mitral valve closed, semilunar valves open.

Diagram Showing the Pumping of the Heart

Diagram to illustrate the action (pumping) of the heart. Labels: aur., auricle; vent., ventricle; v,…