Barts and The London Heart and Chest Centre | For patients | You and your heart
You and your heart
How does it work and what happens when things go wrong?
About your heart
- It is in the middle of your chest, the bottom end pointing slightly to the left.
- The breast bone (sternum) and ribs protect it.
- It pumps blood around the body.
- It is a muscle controlled by electrical impulses passing through it.
- It has a left and right side divided by a thick muscle wall (septum).
- Each side is divided into two; the upper chambers are called atria and the lower chambers are called ventricles.
- There are four valves to ensure that blood flows in one direction.
Blood flow through the heart
Blood returns from all over the body to the right upper chamber (right atrium) of the heart. It flows into the right lower chamber (ventricle), then it is pumped to the lungs, where it receives oxygen. It then flows into he left ventricle before being pumped into the aorta and around the body.
Heart valves
The four valves found inside the heart are the mitral, aortic, pulmonary and tricuspid valves. Each valve acts like a one-way door so that the blood flows in a forward direction, from the upper to the lower chambers (atria and ventricles) and then out of the heart to circulate around the body.
Coronary arteries
Although the heart pumps blood around the body, the heart muscle itself needs its own blood supply. A network of special blood vessels, called coronary arteries, do this. There are two main branches which lie on the surface of the heart and are about 3-4mm wide. These divide into smaller vessels forming the network that supplies the heart with oxygen.
