They are the body's first lines of defense against l foreign pathogens in the body. Neutrophils kill invading pathogens through phagocytosis. Included in these steps of phagocytosis is a multiple signaling system, which is of great importance to the immune system. Even though the neutrophil is beneficial to humans they can also be harmful. They are members of the granulocyte family of leukocytes.
Neutrophils are the most numerous leukocytes in blood.
They are a spherical shaped, motile cell that ranges in size from 10 um to 20 um in diameter. The neutrophil contains many organelles and cell structures that aid in its many functions. It has a single multiobed nucleus and a dense granular appearance of the cytoplasm. The chromatin of the nucleus is coarsely clumped which is considered an abnormal structure. This chromatin structure was taken as evidence that the nucleus was transcriptionally inactive.