PSL201Y1 Lecture Notes - Arteriole, Negative Feedback, Macula Densa
21 Apr 2012
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Document Summary
Filtration is the first step in urine formation. Filtration involves transfer of fluid from the blood into the renal tubule. It creates a filtrate much like that of the interstitial fluid or plasma except the plasma does not have plasma proteins. Therefore filtrate under normal circumstances consist of water and dissolved solutes. Filtration will not allow plasma proteins and blood cells from being filtered. Therefore, at the end of filtration we have a protein free plasma called the glomerular filtrate which is filtered at a phenomenal rate of 125 ml/min or 180l per day. There are three layers through which substances need to pass through in the process of filtration. Fluid leaving the capillaries need to pass through capillary pores or fenestra then through the basement membrane and finally through the filtration slits. These three layers form the filtration barrier or glonerular membrane.
