The Cardiovascular System is responsible for transporting blood carrying oxygen around the body. It consists of:
- the heart - muscular pump that pushes blood through the blood vessels
- blood - carries oxygen to muscles and removes waste products.
- blood vessels - networks of hollow tubes that transport blood through the body.
Millions of red blood cells are produced and destroyed every second. They carry oxygen and transport nutrients but also remove waste products such as carbon dioxide and salt.
Red blood cells are produced in the bone marrow. Blood thickens during exercise due to the removal of water.