text: first off, the nephron is a single long tube within the kidney.  your blood passes through a thing called the glomerulus which separates your red blood cells and your plasma (all the other stuff in your blood) thats how the chemical wastes get into the nephron. There are alot of nephrons in our body and when the wastes go through the nephron special protein channels take stuff we need from the plasma and put it back into our red blood cells.  the neprons are also permeable to water (in some areas) to allow water to come back into our blood.  i hope this is easy to understand when i first learned it, it was kinda confusing.