Blood is a liquid that transports substances around the body. An adult's body contains 5.5 litres of blood.
It carries digested food, vitamins, and minerals from the digestive system to all parts of the body. It transports oxygen from the lungs and carbon dioxide to the lungs.
It takes hormones from the glands to the tissues that need them.
It takes waste to the kidneys from the liver and tissues. It distributes heat around the body. It helps to fight germs and other infections.
