Knowledge Base


Blood is composed of blood cells suspended in blood plasma. The blood cells are mainly red blood cells (erythrocytes), white blood cells (leukocytes) and platelets (thrombocytes). By volume, the red blood cells constitute about 45% of whole blood, the plasma about 54.3%, and white cells about 0.7%.
Blood is circulated around the body through blood vessels by the pumping action of the heart.