There are 2 types of bone marrow: red and yellow. Red marrow is where blood cells are made, yellow is fatty.
There are 2 types of bones as well: those that have spongy bone tissue and those that have compact tissue. The oddly shaped bones and the ends of long bones usually are mostly spongy bone with a layer of compact bone.
Red marrow is found mainly in the flat bones such as hip bone the crest of the iliac bone (the hip), and your breast bone (sternum), skull, ribs, vertebrae and shoulder blades, and in the cancellous ("spongy") material at the proximal ends of the long bones or your legs (the femur) and arms (humerus). Most commonly, red marrow is harvested from the pelvic hip bone.
The shafts of the long bones are hollow in the interior and are filled with yellow marrow in the middle portions, which does not make blood cells. If you look at a round steak or certain beef roasts that contain bones, sometimes
there are long bones that have been cut crosswise and you can see the yellow marrow. Yellow marrow is mostly fatty cells.
At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type. Adults have on average about 2.6 kg of bone marrow, with about half of it being red.
In cases of severe blood loss, the body can convert yellow marrow back to red marrow in order to increase blood cell production.
2007-05-27 16:01:52
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answer #2
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answered by Diane A 7
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