Systemic circulation carries oxygenated blood from the left ventricle, through the arteries, to the capillaries in the tissues of the body. From the tissue capillaries, the deoxygenated blood returns through a system of veins to the right atrium of the heart.

Red blood cells pick up oxygen in the lungs. Blood travels away from the heart and lungs through the arteries (ar-tuh-reez). Red blood cells drop off oxygen to the cells through tiny tubes called capillaries (cap-ill-air-ies). Blood then returns to the heart through the veins (vayns) and the cycle begins again.

Blood comes into the right atrium from the body, moves into the right ventricle and is pushed into the pulmonary arteries in the lungs. After picking up oxygen, the blood travels back to the heart through the pulmonary veins into the left atrium, to the left ventricle and out to the body’s tissues through the aorta.

The pathway of blood through the heart Oxygenated blood is carried to the heart from the lungs in the pulmonary vein. It goes into the left atrium, through the bicuspid valve and into the left ventricle. The ventricle pumps the blood through the semilunar valve, into the aorta and round the body.

1. The right Atria receives oxygen poor blood from the body. THIS IS THE LARGEST PATHWAY OF THE CIRCULATORY SYSTEM!

The left and right atria are smaller chambers that pump blood into the ventricles. The left and right ventricles are stronger pumps. The left ventricle is the strongest because it has to pump blood out to the entire body.

The heart has four chambers, two upper (atrium) and two lower (ventricle), with one atrium and one ventricle on both the right and left side of the heart. Blood that is returning from other areas of the body and is no longer oxygen rich, enters through the top right chamber of the heart.

What Are the Parts of the Heart?

• The two bottom chambers are the right ventricle and the left ventricle. These pump blood out of the heart. A wall called the interventricular septum is between the two ventricles.
• The two top chambers are the right atrium and the left atrium. They receive the blood entering the heart.

Your heart is in middle of your chest, in between your right and left lung. It is, however, tilted slightly to the left.