where are white blood cells are produced
White Blood Cell Production. White blood cells are produced by bone marrow within bone. Some white blood cells mature in the lymph nodes, spleen, or thymus gland. The life span of mature leukocytes ranges from about a few hours to several days.hite blood cells are produced by bone marrow within bone. Some white blood cells mature in the lymph nodes, spleen, or thymus gland. The life span of mature leukocytes ranges from about a few hours to several days.