Creation of a new red blood cell. It all begins with bone marrow.all red blood cells are created from the stem cells that are homed inside of bone marrow.From that point on it takes about 7 full days for a new red blood cell to mature,also two vitamins are needed.vitamin B12 and Folic acid.
What happens exactly after blood leaves the heart?We'll once the blood leaves through the aorta it pumps to the rest of the body through different passage ways.EX arteries,capillaries,and once out of oxygen back to the heart through veins