Production of blood cells

During the foetal life the production of blood cell or take place in different body tissues but mainly in the liver and the bone marrow shortly after birth under normal condition the marrow is the only tissues that continue to produce red cells granulocyte, monocytes, and platelet about 5 years of age the marrow in all the bone is red and cellular. In another case, this red marrow is gradually replaced by yellow and active bone marrow and by the age of 18 to 20 years the active red marrow remain only in the sternum, the ribs, the vertebral the score, the pelvic bone and the proximal end of the long bones.

Lymphocyte also produced in the bone marrow body lymphoid tissues (lymph nodes, spleen, thymus, etc,)

Has a significant function in their maturation. This make element of blood go through a different series of developmental step which consist of the dupplication differentiation and maturation in the lymphoid tissues.

They are release in the circulating peripheral blood only when they are sufficiently developed or matured.

All this blood cell have a predetermined life cycle. The plasma component mainly protein they have a fixed rate of turnover which is often expressed as T50 i.e the time during which the substance is removed from the circulation and replaced. The loss of cells through the normal process of aging physiological conception and sometime by loss from the body is normally compensated for by proliferation, maturation and release of new cells. This process is referred to as haemopoiesis.

Blood composition are in the state of balance between regeneration atlas replacement the state of equilibrium is known as homeostasis.