The heart also has an electrical system inside. Electrical impulses within the heart help it beat at a steady rate and proper rhythm. The heart rate increases when the body needs more blood, such as during intense exercise. Decreases during rest time. The heart has four chambers. The two upper chambers are called the atria, and the two lower chambers are called the ventricles.
Blood flows into the right New Zealand Email List atrium from the veins of the heart and body (except the lungs), then flows into the right ventricle. From there, it flows into the pulmonary artery, which has branches that reach the lungs. The lungs then oxygenate the blood. This oxygenated blood travels from the lungs, through the pulmonary veins that lead back and join together, into the left atrium and then through the left ventricle.
From there, the heart pumps blood through an artery that branches to deliver blood to it and other parts of the body (except the lungs). The heart has four valves that ensure blood flows in the right direction. The heart valves are: tricuspid valve pulmonary valve mitral valve aortic valve The lungs The lungs work with the heart to oxygenate the blood.