GROSS ANATOMY

Detailed explanation-1: -The heart has four chambers: two atria and two ventricles. The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-poor blood to the lungs. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle.

Detailed explanation-2: -A typical heart has two upper and two lower chambers. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood out of the heart.

Detailed explanation-3: -The two atria are thin-walled chambers that receive blood from the veins. The two ventricles are thick-walled chambers that forcefully pump blood out of the heart.

Detailed explanation-4: -The atria perform three different functions during the various phases of the cardiac cycle, i.e. serving as reservoir during systole, passive conduit during early diastole, and booster function during late diastole.