Technische Universität München

The Entrepreneurial University

The human heart weighs between 200 to 400 grams and is a little larger than the size of a fist. The heart is located between the lungs, behind and slightly to the left of the sternum. A double-layered membrane (called the pericardium) surrounds the heart like a sac. The heart is the pump responsible for maintaining adequate circulation of oxygenated blood around the vascular network of the body.

It is a four-chamber pump...
  • ...with the right side receiving desoxygenated blood from the body at low pressure and pumping it to the lungs (pulmonary circulation) and
  • ...the left side receiving oxygenated blood from the lungs and pumping it at a high pressure through the body (systemic circulation).

The upper chambers of the heart are called the left and right atria, and the lower chambers are called the left and the right ventricles. A wall of muscle called the septum separates the left and the right atria and the left and the right ventricles. The left ventricle is the largest and strongest chamber in the heart. The walls of the left ventricle are only about 1 cm thick, but they have enough force to push the blood through the aortic valve. Four types of valves regulate blood flow through the heart. In particular, the tricuspid valve regulates blood flow between the right atrium and the right ventricle. The mitral valve lets oxygenated blood from the lungs pass from the left atrium into the left ventricle. The pulmonary valve controls blood flow from the right ventricle into the pulmonary arteries. The aortic valve opens the way for oxygenated blood to pass from the left ventricle into the aorta.

The heart and the circulatory system make up the cardiovascular system. The heart works as a pump that pushes blood to the organs, tissues, and cells of the body. Blood delivers oxygen and nutrients to every cell and removes carbon dioxide and metabolites. Blood is carried from the heart to the rest of the body through a complex network of arteries, arterioles and capillaries. Blood is returned to the heart through veins.