Final answer:
The five main types of white blood cells are neutrophils, eosinophils, basophils, monocytes, and lymphocytes. Granulocytes include neutrophils, eosinophils, and basophils, while agranulocytes are monocytes and lymphocytes, each with specialized immune functions.
Step-by-step explanation:
Types of White Blood Cells
White blood cells (WBCs), or leukocytes, play a crucial role in the immune system by defending the body against invading microorganisms and other threats. Unlike red blood cells, leukocytes contain nuclei and lack hemoglobin. There are five main types of white blood cells, categorized into granulocytes and agranulocytes. Granulocytes include neutrophils, eosinophils, and basophils, which are identifiable by the presence of granules in their cytoplasm. Agranulocytes comprise monocytes and lymphocytes, which do not contain visible cytoplasmic granules. Each of these leukocyte types has unique and specialized immune functions.
Neutrophils are the most abundant type of WBCs and are the body's first line of defense against infections, as they can quickly respond to invaders through phagocytosis. Eosinophils play a significant role in combating parasitic infections and are involved in allergic reactions. Basophils are responsible for releasing histamine in allergic responses. Monocytes transform into macrophages and dendritic cells to phagocytize pathogens and dead or abnormal cells. Lastly, lymphocytes are crucial for the adaptive immune system, which includes both B cells (producing antibodies) and T cells (destroying infected cells).