Science revision

The heart

Biology revision

• The heart pumps blood around the body
• Mammals have a double circulatory system:
• The first system controlls the heart to the lungs. Then the deoxygenated blood is pumped to the lungs which provides oxygen. After this the blood will return to the heart
• The second system connects the heart to the rest of the body. In this process the heart will pump oxygenated blood throughout the body, it will then give up its oxygen and the deoxygenated blood will return to the heart to be pumped out to the lungs again.
• Not all animals have a double circulatory system, for example fish do not
• Advantages of a double circulatory system: 
• It allows the blood to be…