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There are two types of marrow, red and yellow. The former produces the blood cells; the latter, which is mainly formed of fatty tissue, normally has no blood-producing function. During infancy and early childhood all bone marrow is red. But gradually, as one gets older and less blood cell production is needed, the fat content of the marrow increases as some of it turns from red to yellow. Red marrow is present in adulthood only in the flat bones of the skull, the sternum, ribs, vertebral column, clavicle, humerus, and part of the femur. However, under certain conditions, as after hemorrhage, yellow marrow in other bones may again be converted to red and resume its cell-producing functions.
The marrow is occasionally subject to disease, as in aplastic anemia, which may be caused by destruction of the marrow by chemical agents or excessive x-ray exposure. Other diseases that affect the bone marrow are leukemia, pernicious anemia, myeloma, and metastatic tumors.
See also: gelatinous bone marrow, red bone marrow, yellow bone marrow.
bone marrowThe soft, spongy tissue in the centre of large bones, which is composed of mature and immature blood cells and fat. Bone marrow produces leukocytes, erythrocytes and platelets from cognate stem cells, and is the body’s most radiation-sensitive tissue.
BONE MARROWA trial assessing the safety of the proprietary Biosense system for percutaneous injection of autologous bone marrow into ischaemic myocardium of patients with refractory angina.
Major acute coronary events at 30 days.
Autologous bone marrow cell injection in patients with ischemia is safe and results in a sustained beneficial effect on anginal symptoms, myocardial perfusion and left ventricular function.
bone mar·row(bōn mar'ō) [TA]
bone marrowMarrow (1).
spinal marrowMarrow (2).illustration
bone marrowThe substance contained within bone cavities. This is red in the flat bones and the vertebrae, and yellow from fat in adult long bones. The volume of the red marrow in young adults is about 15 l. The basic marrow stem cell differentiates into HAEMOGLOBIN-carrying red blood cells, the white blood cells of the immune system and the blood PLATELETS which are essential for BLOOD CLOTTING.
bone marrowa modified connective tissue of a vascular nature found in long bones and some flat bones of vertebrates; it is responsible for the manufacture of blood cells.
bone mar·row(bōn mar'ō) [TA]
Patient discussion about Bone marrow
Q. What is a bone marrow transplant? I wanted to enter myself as a potential bone marrow donor and wanted to know first of all what bone marrow is? What does a bone marrow transplant mean and how is it done?
Q. What is Leukemia? My brother's best friend has been diagnosed with Leukemia. What is it? Is it dangerous? Can you recover from it?