Heart and blood vessels

Anatomy of the heart

The heart consists of four chambers that receive blood from the body and pump out blood to it.

• Atria
  • two upper chambers
  • receive blood coming back to the heart
• Ventricles
  • two lower chambers
  • pump the blood out to the heart

The heart also consists of four valves that prevent backward flow of blood. Each valve has flaps, called leaflets, that allow forward flow of blood and prevent the backward flow.

• Tricuspid valve - between the right atrium and right ventricle
• Pulmonary valve - between the right ventricle and pulmonary artery
• Mitral valve - between the left atrium and left ventricle
• Aortic - between the left ventricle and aorta

Valves are flaps that act as one-way inlets for blood entering and leaving the chambers and ventricles.

How do blood vessels work?

Blood vessels bring blood to the lungs, where oxygen enters the bloodstream, and then to the body.

• Inferior and superior vena cavae - bring oxygen-poor (blue) blood from the body into the right atrium
• Pulmonary artery - moves oxygen-poor (blue) blood from the right ventricle into the lungs, where oxygen enters the bloodstream
• Pulmonary veins - bring oxygen-rich (red) blood to the left atrium
• Aorta - sends oxygen-rich (red) blood to the body

An electrical system controls how fast the heart beats.

A network of arteries and veins also carry blood throughout the body.

• Arteries transport blood from the heart to the body tissues.
• Veins carry blood back to the heart.