Leukocytes: Learn about leukocytes

Learn about leukocytes, the major cellular components of the inflammatory and immune system, and their types, production, movement and functions. Find out how to count leukocytes in urine and blood, and what abnormalities indicate. White blood cells or WBCs are also known as leukocytes. WBCs are essential components of immune system as they play a crucial role in protecting the body from infections and diseases by circulating through the bloodstream and tissues to respond injury or illness. Types of leukocytes can be classified in standard ways. Two pairs of broadest categories classify them either by structure (granulocytes or agranulocytes) or by cell lineage (myeloid cells or lymphoid cells). Leucocytes, also known as white blood cells (WBCs), are colorless, transparent cells that circulate in the blood and lymph.