The blood is made up of fluid called plasma and three types of cells each type has special functions. The red blood cells give blood its color.
Some blasts stay in the marrow to mature.
Some travel to other parts of the body to mature. Normally, blood cells are produced in any orderly, controlled way, as the body needs them. This process helps keep us healthy. The marrow inside your bones is an active tissue with a rich blood supply. Your bone marrow produces most of your blood cells, including all of the red cells and platelets and most of the white cells.