Bone Marrow is the Site of Blood Formation

Function of Bone Marrow is:

The bone marrow is one of the largest organs in the human body, and it is the principal site for blood cell formation. In the normal adult, daily marrow production amounts to approximately 2.5 billion red cells, 2.5 billion platelets, and 1 billion granulocytes per kilogram of body weight. The rate of production adjusts to actual needs and can vary from nearly zero to many times normal.

History of bone marrow is:

Until the late 19th century, blood cell formation was thought to be the prerogative of the lymph nodes or the liver and spleen. In 1868, Neuman and Bizzozero3 independently observed nucleated blood cells in material squeezed from the ribs of human cadavers and proposed that the bone marrow is the major source of blood cells.

The first in vivo marrow biopsy probably was done in 1876 by Mosler, who used a regular wood drill to obtain marrow particles from a patient with leukemia. Studies by Arinkin in 1929 established marrow aspiration as a safe, easy, and useful technique.

General considerations on bone marrow

Kinetic studies of marrow cells, using radioisotopes and in vitro cultures, have shown that cell lineages consist of maturing end cells with a finite functional life span. The cells are capable of limited proliferation before they reach full maturation and do not have the capacity for self-renewal.

The more mature pools consist of differentiated unipotential progenitor cells, with their maturation restricted to single cell lineages and no capacity for self-renewal. The proliferative activity of these pools involves humoral feedback from peripheral target tissues and cell–cell and cell–matrix interactions within the microenvironment of the marrow.

The marrow stroma provides a unique structural and chemical environment (niches) that supports the survival, differentiation, and proliferation of pluripotential HSCs. Primitive hematopoietic stem cell interactive niches have been identified at the structural and molecular 11 levels and are dynamically controlled by bone morphogenetic proteins (BMPs) and factors regulating intramedullary xsosteoblastic cells.