The human heart is a four-chambered organ that comprises two atria, two ventricles, four valves, two primary veins and the largest artery in the body. The size of a typical adult heart is comparative to a closed fist, weighing approximately 11 ounces, as noted by The Franklin Institute.
The heart is the primary organ of the circulatory system, which primarily functions as a muscular pump. It forces blood through the bloodstream to transport vital materials, such as oxygen, via an interconnected network of blood vessels. Cardiac muscles are said to expand and contract more than 2.5 billion times throughout the life span of an individual, as stated by California State University.
The left side of the heart contains an upper atrium and lower ventricle, which are separated by the septum from the upper atrium and lower ventricle found on the right side. The heart has four major valves that regulate blood flow. The tricuspid valve sits between the right atrium and right ventricle, while the mitral valve connects the left atrium to the left ventricle. The pulmonary valve is located between the right ventricle and the pulmonary artery of the lungs while the aortic valve lies between the left ventricle and the largest artery called the aorta.
Oxygen-starved blood enters the right side of the heart via two prominent veins known as the inferior and superior venae cava. When the blood is replenished with oxygen from the lungs, it is pumped out from the left side of the heart through the aorta.