Figure 1. Diagram illustrating roles of urea channels in the process responsible for accumulation of urea in renal inner medulla.
See text for explanation. DVR, descending vasa recta; AVR, ascending vasa recta; OS-OM, outer stripe of outer medulla; IS-OM, inner stripe of outer medulla; IM, inner medulla; IMCD, inner medullary collecting duct. UT-B, UT-A1, UT-A2, and UT-A3 are urea channel isoforms described in the text.