In this note, we are going to discuss the structure and functions of the bone marrow.
The bone marrow is both a hematopoietic organ and a primary lymphoid organ.
It is responsible for hematopoiesis (blood cell formation), the process of creating new blood cells, including erythrocytes, leukocytes, platelets, and many others.
Bone marrow is classified into two types:
- Red bone marrow, which is found within the trabecular spaces of the spongy (cancellous) substance of flat and short bones, as well as in the epiphyses of long (tubular) bones. It is highly vascularized and actively involved in hematopoiesis.
- Yellow bone marrow, which is located in the medullary cavities of the diaphyses of long (tubular) bones in adults. It contains a high concentration of adipose tissue and has fewer hematopoietic centers.
During fetal development and until approximately the age of 5 years, red bone marrow is present in almost all bones of the skeleton. After this period, in most bones (except for those previously mentioned), red bone marrow gradually transforms into yellow bone marrow, as hematopoietic islands are replaced by adipose tissue.
The bone marrow receives blood from the same arteries that supply nutrients to the surrounding bone.
The nutrient artery and two nutrient veins pass through the nutrient canals to reach the bone marrow.
Bone marrow
- Bone marrow
- medulla ossium
- Nutrient foramen
- foramen nutricium
- Nutrient artery
- arteria nutricia
- Nutrient veins
- venae nutriciae
- Nutrient canals
- canales nutricii
