Granulocytes are a type of white blood cell that play a crucial role in the immune system. They are characterized by the presence of granules in their cytoplasm, which contain enzymes and other substances that help fight infections. There are three main types of granulocytes: neutrophils, eosinophils, and basophils, each with specific functions in responding to different types of pathogens. These cells are produced in the bone marrow and are released into the bloodstream. Neutrophils are the most abundant and primarily target bacteria, while eosinophils are involved in combating parasites and allergic reactions. Basophils release histamine during allergic responses and inflammation, contributing to the body's defense mechanisms.