Erythrocytes are biconcave disc shape. in other words it looks like a plate. The function of the biconcave disc shape is to increase surface to volume ratio and to allow diffusion of the oxygen and carbon dioxide. Red blood cells do not have nucleus. They contain pigment called hemoglobin which allowing the oxygen and carbon dioxide to bind.Tthe erythrocytes are produced in red bone marrow. the process of red blood cells production is called as erythropoiesis. The life span of erythrocytes is 120 days. The destruction of erythrocytes will occur at spleen and liver after 120 days. 

WHITE BLOOD CELLS ( LEUKOCYTES )

NEUTROPHILS

Neutrophils are most abundant type of leukocytes or whitw blood celss. They has diameter of 12-15 nanometer. They consists of 2-5 lobes of nucleus which connected by the fine filament. They has transparent cytoplasm with pink coloured granules. The immature neutrophils have a band-shaped of horse-shoe shaped nucleu. Thus, it called as band cells. The main function of neutrophils are to fight against baterial infection and imflammation.

EOSINOPHILS

Eosinophils have bilobed nucleus and the cytoplasm is full with pink granules. They are few seen in normal blood. Eosinophils have same size as neutrophils. The main function of eosinophils is to deal with parasitic infection.

BASOPHILS

Basophils are the rarest leukocytes which are less than 1% of white blood cells. The cytoplasm appears dark purple in coloured granules. They consists of bilobed or trilobed nucleus which are hard to see as the nucleus are commonly overlapped with granules. The main function of basophils is to deal with allergic reaction related with histamine.

MONOCYTE

Monocytes are the biggest leukocytes. It is well-known among the leukocytes as it consists of kidney shaped nucleus. It has transparent cytoplasm with ground glass appearance. Monocytes bind to pathogens and presenting them to T cells. It undergoes phagocytosis function.

LYMPHOCYTES

Lymphocytes are commonly appeared in leukocytes. It is smaller than other leukocytes but larger than the red blood cells. It appears transparent cytoplasm, round and large nucleus occupying most of cytoplasm. There are 3 types of lymphocytes :