Cells generate waste products such as cellular debris and ammonia, which can enter the blood supply and subsequently be taken up by the lymphatic system.

“But keep in mind that those cells are fed by the blood supply, and stuff gets into the blood supply by way of what you breathe, okay? So, you can inhale a virus, for instance, bacteria that could be in food, bacteria from things that you touch that somehow gets beneath the skin and into your blood supply through a scratch or a cut, maybe a bite, these sorts of things. Or maybe you cut yourself with a knife that had some bacteria, it gets into your blood supply. And so, you have foreign bodies, contaminants within your blood supply. Some of that is going to get out into the interstitial space. Some of that will be taken up by the lymphatic system.”