What a nephron looks like close up
This is what a nephron looks like – basically, it’s a bendy tube (called a tubule) surrounded by tiny blood vessels. Substances are transferred between the blood vessels and the tube, to remove waste and adjust the balance of water and salts in the bloodstream.
What goes into the tubule is called the “filtrate” because it has been filtered out of the blood.
Here is a simple overview of the transfer of substances in the nephron: