Which white blood cell type is NOT formed in bone marrow?

Which white blood cell type is NOT formed in bone marrow?

• A. Neutrophils
• B. Lymphocytes
• C. Monocytes
• D. Eosinophils

Answer: (B)

White blood cell production mostly centers in the bone marrow, where several lineages finish their maturation and enter circulation. The difference with lymphocytes is that their development continues in lymphoid tissues after their initial formation. T lymphocytes mature in the thymus, while B lymphocytes complete maturation in peripheral lymphoid organs. Because their final maturation occurs outside the bone marrow, lymphocytes are not formed there in the same sense as the other WBC types. That makes them the best answer. Neutrophils, monocytes, and eosinophils go through full maturation in the bone marrow before being released.

White blood cell production mostly centers in the bone marrow, where several lineages finish their maturation and enter circulation. The difference with lymphocytes is that their development continues in lymphoid tissues after their initial formation. T lymphocytes mature in the thymus, while B lymphocytes complete maturation in peripheral lymphoid organs. Because their final maturation occurs outside the bone marrow, lymphocytes are not formed there in the same sense as the other WBC types. That makes them the best answer. Neutrophils, monocytes, and eosinophils go through full maturation in the bone marrow before being released.