do all bones have 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.On average, bone marrow constitutes 4% of the total body mass of humans; in an adult weighing 65 kilograms (143 lb), bone marrow typically accounts for approximately 2.6 kilograms (5.7 lb).he stroma of the bone marrow is all tissue not directly involved in the marrow's primary function of hematopoiesis. Yellow bone marrow makes up the majority of bone marrow stroma, in addition to smaller concentrations of stromal cells located in the red bone marrow.