Leu­ko­cytes

White blood cells. The main task of the leu­ko­cytes is to defend against patho­gens. The term leu­ko­cytes encom­pas­ses many dif­fe­rent cell types (gra­nu­lo­cytes, lym­pho­cytes and mono­cytes). They are for­med in the red bone mar­row of the long tubu­lar bones and in the lympha­tic system.