where is bone marrow found in the human body
Bone marrow Bone marrow is the flexible tissue in the interior of bones. In humans, red blood cells are produced by cores of bone marrow in the heads of long bones in a process known as hematopoiesis.[2] On average, bone marrow constitutes 4% of the total body mass of humans; in an adult having 65 kilograms of mass (143 lb), bone marrow typically accounts for approximately 2.6 kilograms (5.7Â lb). The hematopoietic component of bone marrow produces approximately 500 billion blood cells per day, which use the bone marrow vasculature as a conduit to the body's systemic circulation.[3] Bone marrow is also a key component of the lymphatic system, producing the lymphocytes that support the body's immune system.[4] In addition to hematopoietic cells, the marrow is composed of marrow adipose tissue as well as trabecular bone. The interplay between these different cell types and the local factors they produce can have an effect on hematopoietic cells within the hematopoietic stem cell niche.