The components of formed elements are Erythrocytes, Leucocytes and platelets. Its functions are : (a) Erythrocytes or RBCThese play a significant role in transport of respiratory gases.(b) Leucocytes or white blood cells (WBC)There are two types of WBC granulocytes and agranulocytes. The granulocytes include neutrophils, eosinophils and basophils and the agranulocytes include lymphocytes and neutrophils. Each of these cells help the body in fighting against the invading pathogen and protect the body. Neutrophil and MonocyteThese cells are phagocytic. They engulf and destroy the foreign organism entering the body.BasophilsIt secrets histamine, serotonin, heparin etc. which are involved in inflammatory reaction.EosinophilsIt helps in resisting infection and also helps in allergic reaction.Lymphocytes: These are of two types ‘B’ and ‘T’ forms which are responsible for immune responses of the body. (c) Platelets or thrombocytesThey are mainly involved in coagulation or clotting of blood.