Name: Amy J.
Do all bones have real bone marrow?
When you say "real" bone marrow what do you mean? There are 2 types of bone
marrow: red and yellow. Red marrow is where blood cells are made.
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 around
them. So bones like the breastbone (sternum), and the ends of your leg and
arm bones have red marrow in them. The shafts of the long bones are hollow
and are filled with yellow marrow, 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 that fills their center.
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Update: June 2012