Blood is a liquid that carries nutrients and removes waste. It moves through the body’s cardiovascular system. The heart pumps blood through the blood vessels to all parts of the body. Blood is an important part of the body and it consists of cells. There are three main types of blood cell: red cells, white cells, platelets, and plasma. Red blood cells transport oxygen, white blood cells (leukocytes) help to keep the body healthy. The plasma is watery part of the blood, which contains nutrients, chemicals, hormones, and wastes.
For a day the heart of an adult man pumps about 10,000 liters of blood. The average heart rate of a healthy person is 60-80 beats per minute.