Granular Leukocytes

Granular leukocytes, or granulocytes, are white blood cells with distinctive cytoplasmic granules and lobed nuclei, comprising neutrophils, eosinophils, and basophils. Neutrophils, the most abundant, rush to infection sites to phagocytose bacteria, releasing enzymes and reactive oxygen species. Eosinophils target parasites and modulate allergic responses with major basic protein and histamine. Basophils, rarest in blood, release heparin and histamine during allergic reactions, similar to tissue mast cells. All originate in bone marrow and play key roles in innate immunity.