Which type of agranulocytic leukocyte transforms into a macrophage after migrating from the blood into the tissues?

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

Answer: (B)

Verified step by step guidance

1. Understand that agranulocytic leukocytes are white blood cells that lack visible granules in their cytoplasm when stained and viewed under a microscope.
2. Recall the two main types of agranulocytes: lymphocytes and monocytes.
3. Know that monocytes circulate in the blood and, upon migrating into tissues, differentiate into macrophages, which are large phagocytic cells involved in engulfing pathogens and debris.
4. Recognize that lymphocytes do not transform into macrophages; instead, they are involved in adaptive immunity (e.g., B cells and T cells).
5. Conclude that the agranulocytic leukocyte that transforms into a macrophage after leaving the bloodstream is the monocyte.