The heart is the muscle that controls the flow of blood to all other regions of the body and is one of the most vital components of the human body. Anatomically, the heart consists of four chambers, the upper right and left atria and the lower right and left ventricles. It is the only organ of the body that consists of cardiac muscle tissue and its own electrical conducting system which causes it to contract. The contraction of the heart is the mechanism by which the heart pumps blood.
The conduction system of the heart causes the atria to contract first, which forces blood from the atria into the ventricles. After a delay, the ventricles contract and force blood out of the heart through arteries to be distributed to the body. The function of the delay in the conduction system is so that the atria and ventricles don’t contract at the same time, because contraction at the same time wouldn’t force blood out of the heart, thus rendering it useless.
The right atrium receives deoxygenated blood from the Inferior and Superior Vena Cava and pumps it into the right ventricle. From the right ventricle, the deoxygenated blood is pumped into the Pulmonary Trunk and distributed to the lungs where it is oxygenated. This oxygenated blood is then returned to the heart through the left atrium via the pulmonary veins, where it is then pumped into the left ventricle. The oxygenated blood leaves the left ventricle through the Aorta and is distributed to other parts of the body to provide nutrients and oxygen in order to keep the body healthy.
The chambers of the heart also consist of four valves. All of these valves work in one direction only – allowing blood to flow through them, but not in the reverse direction, thus maximizing cardiac output. The atrioventricular valves are the barriers that separate blood from the atria and ventricles. On the right side, the tricuspid valve separates the right atrium and ventricle and on the left side, the bicuspid valve separates the left atrium and the left ventricle. There are also valves separating the ventricles from their respective arteries. On the right side the right semilunar valve separates the right ventricle and the Pulmonary Trunk, and on the left side, the left semilunar valve separates the left ventricle from the Aorta. There are defects in the heart that cause the valves to leak in the opposite direction and causes decreased blood flow from the heart.
The heart and its chambers are highly evolved to provide a perfect and efficient system for gas and nutrient exchange for every organ and tissue of the human body. The ability of the heart to pump blood to all regions of the body allows our bodies to successfully cope with all of the daily stresses that we put it through.