Do humans have the same blood that we had as a kid? How come blood doesn’t expire inside of us since we range from different temperatures and are exposed to oxygen etc.

Question

Do we somehow maintain the same blood for the rest of our lives and we just pump more if we lose some. Blood expires in hospitals and not when inside of us?

In: Biology

Answer 1

Your body is constantly destroying old red blood cells and making new ones, so any given red blood cell that’s currently in your blood stream isn’t that old. The blood plasma which the red blood cells are suspended in is basically water, so it doesn’t “expire.”