Fig. 4.

Flow and composition within a single long model VR, running through a hyperosmolar medulla. In the OM, interstitial NaCl concentration doubles from cortex to IM border; in the IM, NaCl concentration remains high, and interstitial urea increases from 20 to 500 mM from OM to papillary tip. Within each column of the figure, the three panes display vessel protein concentration (top), plasma flow (bottom), and the osmotic difference between vessel fluid and the local interstitium (middle). The two columns correspond to initial plasma flow of either 12 or 72 nl/min (0.2 and 1.2 nl/s).