Final answer:
Monocytes represent 2-8% of WBCs, originating from myeloid stem cells, and differentiate into macrophages that help in immune response.
Step-by-step explanation:
Monocytes are a type of white blood cell (WBC) that play a crucial role in the immune system by phagocytizing debris and pathogens, as well as assisting in the immune response. They originate from myeloid stem cells and represent about 2-8 percent of the total leukocyte count in the blood.
These cells are identified by their characteristically large size, typically 12-20 µm, and their indented or horseshoe-shaped nuclei. Once monocytes leave the circulation, they differentiate into macrophages, which are responsible for engulfing and digesting a variety of foreign substances and cellular debris.
Macrophages play a crucial role in the immune response by releasing antimicrobial defensins and chemotactic chemicals, which attract other leukocytes to sites of infection. Abnormal counts of monocytes can indicate various health conditions, with high levels associated with certain infections and diseases, and low counts often indicating bone marrow suppression.