Which blood cell acts as a precursor to macrophages and is capable of migrating into tissues?

Which blood cell acts as a precursor to macrophages and is capable of migrating into tissues?

• A. Megakaryocyte
• B. Lymphocyte
• C. Monocyte
• D. Eosinophil

Answer: (C)

The concept being tested is how certain white blood cells travel through the blood and then become other cells in tissues. Monocytes are produced in the bone marrow and circulate in the bloodstream; they can exit into tissues through diapedesis and differentiate there into macrophages. Macrophages are the tissue-resident phagocytes that engulf microbes and debris and present antigens to help coordinate the immune response. This lineage explains why monocytes act as the precursors to macrophages and are capable of migrating into tissues. Megakaryocytes stay in the marrow to produce platelets. Lymphocytes are involved in adaptive immunity and do not typically become macrophages. Eosinophils defend against parasites and participate in allergic responses, without differentiating into macrophages.

The concept being tested is how certain white blood cells travel through the blood and then become other cells in tissues. Monocytes are produced in the bone marrow and circulate in the bloodstream; they can exit into tissues through diapedesis and differentiate there into macrophages. Macrophages are the tissue-resident phagocytes that engulf microbes and debris and present antigens to help coordinate the immune response. This lineage explains why monocytes act as the precursors to macrophages and are capable of migrating into tissues. Megakaryocytes stay in the marrow to produce platelets. Lymphocytes are involved in adaptive immunity and do not typically become macrophages. Eosinophils defend against parasites and participate in allergic responses, without differentiating into macrophages.