OSMT (Ontario Society of Medical Technologists) Practice Exam

The principal cells of the reticuloendothelial system are:

1. neutrophils

2. macrophages

3. T cells

4. B cells

The correct answer is: macrophages

The correct answer is macrophages, as they are the principal cells of the reticuloendothelial system, which is now often referred to as the mononuclear phagocyte system. This system plays a crucial role in the immune response, particularly in the identification and phagocytosis of pathogens and debris. Macrophages are derived from monocytes and are found throughout the body, where they act as key players in inflammation and immune surveillance. They not only engulf and digest pathogens but also present antigens to T cells, facilitating the adaptive immune response. They are integral to both innate and adaptive immunity and are involved in various physiological processes. The other cells mentioned serve different roles. Neutrophils are a type of white blood cell primarily involved in the acute inflammatory response and are typically the first responders to sites of infection. T cells and B cells are lymphocytes crucial for adaptive immunity; T cells primarily manage cellular immunity and B cells are responsible for antibody production. While all these cells contribute to the immune response, it is macrophages that serve as the principal cells of the reticuloendothelial system, highlighting their fundamental role in the body's defense mechanisms.