How does the heart control blood circulation?
The heart is a muscular pump that serves as the master control station for blood circulation. The heart is divided into 4 chambers. The upper chambers are called the right and left atrium, and the lower chambers are called the right and left ventricle. Blood from all parts of the body drains into the right atrium, passes through a valve and reaches the right ventricle. The right ventricle contracts with each heartbeat and blood is pushed into the lungs, where it gives off carbon dioxide, takes up oxygen and returns via the pulmonary veins to the left atrium. During relaxation of the left ventricle, the blood passes from the left atrium to the left ventricle where, with each heartbeat, it is ejected through the aortic valve into the aorta. How does the healthy heart circulate blood? Normally, this powerful muscle pumps 5 to 6 quarts of blood per minute during rest and more than 20 quarts per minute during exercise, such as walking or climbing stairs. When healthy, the heart automaticall
