Final answer:
Granulocytes, a category of white blood cells, include three types: neutrophils, eosinophils, and basophils, each characterized by distinct granules and a lobed nucleus. These cells play crucial roles in the body's immune response, including phagocytosis and combatting infections.
Step-by-step explanation:
Within the immune system, white blood cells (WBCs) are essential components that serve various functions. Among the WBCs, granulocytes represent a category distinguished by the presence of granular inclusions in their cytoplasm and a lobed nucleus. There are three types of granulocytes: neutrophils, which have small granules that stain light lilac and a nucleus with two to five lobes; eosinophils, with granules staining reddish-orange and a two to three-lobed nucleus; and basophils, containing large granules that stain dark blue to purple and a two-lobed nucleus.
Neutrophils are often termed first-responders during injuries or infections due to their high mobility and phagocytic capability. Eosinophils play a critical role in combating parasitic infections and allergic reactions. Basophils are important for immune responses, being involved in inflammatory reactions and releasing histamine.
Conversely, agranulocytes—which include lymphocytes and monocytes—do not have such distinct granules. Lymphocytes are vital for the adaptive immune system, including B and T cells, while monocytes mature into macrophages and dendritic cells, key players in phagocytosis and antigen presentation, respectively.