Which of the following are referred to as mononuclear phagocytes?

• A. Lymphocytes and basophils.
• B. Mast cells and eosinophils.
• C. Basophils and eosinophils.
• D. Monocytes and macrophages.

Answer: (D)

Verified step by step guidance

1. Understand the term 'mononuclear phagocytes': These are immune cells that have a single round nucleus and are capable of phagocytosis, which is the process of engulfing and digesting cellular debris and pathogens.
2. Identify the types of cells that fit the description of mononuclear phagocytes: Monocytes and macrophages are the primary cells that are classified as mononuclear phagocytes.
3. Differentiate mononuclear phagocytes from other immune cells: Lymphocytes, basophils, mast cells, and eosinophils are not classified as mononuclear phagocytes because they either have different functions or nuclear structures.
4. Recognize the role of monocytes: Monocytes circulate in the bloodstream and migrate into tissues where they differentiate into macrophages.
5. Understand the function of macrophages: Macrophages reside in tissues and are key players in the immune response, responsible for phagocytosing pathogens and presenting antigens to T cells.