Which two types of white blood cells are commonly found in tissues?

• A. Eosinophils and Basophils
• B. Neutrophils and Lymphocytes
• C. Mast cells and Macrophages
• D. Monocytes and B cells

Answer: (C)

Mast cells and macrophages are the two types of white blood cells commonly found in tissues. Mast cells play a crucial role in the immune response, particularly in allergy and inflammatory reactions. They release histamine and other mediators that contribute to inflammation and tissue healing. Macrophages, on the other hand, are pivotal in phagocytizing pathogens and dead cells, playing a fundamental role in innate immunity and tissue repair.

The presence of these cells in tissues is essential for monitoring and responding to pathogens that may invade the body. Their location allows for a rapid response to tissue injury or infection, making them vital components of the immune system outside of the bloodstream.

In contrast, while neutrophils, lymphocytes, and other white blood cells circulate in the bloodstream and can migrate to tissues under certain conditions, mast cells and macrophages are established within the tissues themselves, supporting their immediate functionality in the immune defense mechanisms.