Biology 5.1 Structure of the Heart

Heart = muscular organ, lies in the thoracic cavity behind the sternum (breast bone).

Structure of the human heart

Heart = two seperate pumps lying side by side, the left deals with oxygenated blood and the right deals with deoxygenated blood.

Each pump has two chambers:

• Atrium = thin walled and elastic, stretches as it collects blood, only has to pump blood small distance to ventricle, has thin muscular wall.
• Ventricle = thicker muscular wall, has to pump blood to rest of the body.

Blood has to pass through tiny capillaries in lungs in order to present a large surface area for the exchange of gases - leads to a large drop in pressure so bloody flow in the rest of the body is very slow.

Mammals = system that returns blood to the heart after it has been to lungs…