Blood stem cells are stem cells produced in the bone marrow. They are the starting point for
the creation of all new cells of the blood and immune system: They can develop into red and
white blood cells and platelets. Once the maturation process is complete they leave the bone
marrow and enter the bloodstream, where they perform their job as specialized cells.
Depending on their function, the blood cells die after a few days or months and are therefore
constantly replaced by new cells.