How does blood circulate in and out of the heart?

Cardiac physiology. Blood moves from the heart into the aorta as oxygenated blood under the force of the systolic contraction. Arterial blood passes through the nonpulsatile microcirculation passively based on the tone of the afferent and efferent arterioles and venules. Once back in the venous microcirculation the veins coalesce and form veins taking blood to the heart by internal valves and compression by muscles.