We just learned about the Proximal Tubule.
Another part of the kidneys is the Loop of Henle.
This is a tube that carries liquid down and back up, and helps separate the dirty liquid which turns into urea going back up at the end of the loop.
![Loop of Henle](https://upload.wikimedia.org/wikipedia/commons/thumb/2/26/Kidney_nephron_molar_transport_diagram.svg/640px-Kidney_nephron_molar_transport_diagram.svg.png)
(from: wikipedia - loop of henle)
Kid Facts - Blast from the past: Intertragic Notch