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…