What does bone marrow do in the body?

Bone marrow is the organic material that fills the
cavities of the inside/medial portion of the bones. It is a connective and hematopoietic
tissue. Marrow helps form or synthesize blood cells. Hematopoiesis is the process of
blood cell formation which occurs in red bone marrow. The five types of bones are long
bones (example, humerus), short bones (wrist, carpals), flat bones (frontal,forehead),
irregular bones (vertebrae), and round bones or sesamoid (patella, kneecap). The
epiphysis (proximal or distal ends) of long bones contain red bone marrow so this is
where hematopoiesis occurs. The shaft of long bones (diaphysis) contains yellow bone
marrow (in adults) and is a fatty, inactive form of marrow that also serves as a
connective tissue.