Neutrophil granulocyte

The neutrophil granulocyte (often referred to as just a neutrophil) is the most abundant type of leukocyte in mammalian blood, and are an essential part of normal immune functioning. The term neutrophil granulocyte refers to the fact that the cytoplasm of neutrophils contains granulae, which are not strongly eosinophilic or basophilic when H&E stained; thus, the cytoplasm of a neutrophil stains a neutral pink rather than a strong blue (basophile) or red (eosinophile) when using the standard H&E stain.

Anatomy and occurence
The average neutrophil granulocyte is rougly spherical, has a diameter of 12-15µm, a lobular nucleus (typically 3 lobes) often without a discernible nucleolus.

The neutrophil granulocyte is the most abundant leukocyte in human blood, accounting for about 70% of the total leukocyte count in a normal human being. What is considered a normal neutrophil count varies between laboratories, but is usually from 2.5 - 7.5 x 109/L. A count lower than that is termed neutropenia and is a serious immunocompromising condition.

Activation
The neutrophil granulocyte is generally activated either through direct, innate recognition of potentially pathogen moieties (for instance peptidoglycan) or viz. bound opsonins