<P> 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 . 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 ( 5.7 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 . Bone marrow is also a key component of the lymphatic system , producing the lymphocytes that support the body 's immune system . 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 . </P>
<P> 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 . 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 ( 5.7 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 . Bone marrow is also a key component of the lymphatic system , producing the lymphocytes that support the body 's immune system . 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 . </P>
where is bone marrow found in the human body
where is bone marrow found in the human body
in the interior of bones
in the interior of bones