The circulatory system and the heart
- The double circulation system in humans consists of blood vessels, blood and the heart.
- The heart is organ that pumps blood around the body
- Valves prevent backflow of blood
- CHAMBERS AND MAIN BLOOD VESSELS
Keeping the blood flowing
- Arteries, veins and capillaries are the main type of blood vessels.
- Substances diffuse between the blood and the cells in the…