And the white blood cells we call macrophages, which are phagocytic cells, essentially engulfed, digest and recycle the different components of red blood cells. So to summarize what we describe and to discuss how this process takes place, let's take a look at the following diagram. So, let's begin in region number one. So this is our bone, this is the bone marrow. And inside the bone marrow, our hemopoetic stem cells essentially form red blood cells. Those red blood cells mature, they end up being released into our blood plasma.