The veins and muscles that aid in and regulate blood flow throughout
the body make up the circulatory system. Circulation is the term for this
action. The heart, arteries, capillaries, and veins are the system’s major
components.

The left ventricle of the heart releases blood into the aorta once
circulation starts. The aorta is the body’s biggest artery. There is plenty
of oxygen in the blood leaving the aorta. This is necessary for the body’s
and the brain’s cells to function properly. The smallest arterioles are
reached by the oxygen-rich blood as it passes through the body’s
network of arteries.

The blood passes via a network of veins on its route back to the heart.
When the blood enters the lungs, carbon dioxide, a waste product, is
eliminated and replaced with new oxygen that has been inhaled.