Describe, in brief, the function of heart.
Heart pumps blood to the different parts of the body. When the heart muscles contract, they squeeze the blood through the atria and then through the ventricles.
Oxygenated blood, from the lungs, flows into left atrium and then to all parts of the body.
Deoxygenated blood, returning from the body, flows into the right atrium and then to lungs for oxygenation.