Glomerular filtration

Glomerular filtration - the sum of those that oppose...

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Glomerular filtration When blood enters the glomerular capillaries, water and solutes are forced into the glomerular  capsule. Passage of cells and certain molecules are restricted as follows:  The  fenestrae  (pores) of the capillary endothelium are large, permitting all  components of blood plasma to pass except blood cells.  A basement membrane (consisting of extracellular material) that lies between the  capillary endothelium and the visceral layer of the glomerular capsule blocks the entrance  of large proteins into the glomerular capsule. The filtration slits between the pedicels of the podocytes prevent the passage of  medium-sized proteins into the glomerular capsule. The  net filtration pressure (NFP)  determines the quantity of filtrate that is forced into the glomerular  capsule. The NFP, estimated at about 10 mm Hg, is the sum of pressures that promote filtration less 
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Unformatted text preview: the sum of those that oppose filtration. The following contribute to the NFP: The glomerular hydrostatic pressure (blood pressure in the glomerulus) promotes filtration. The glomerular osmotic pressure inhibits filtration. This pressure is created as a result of the movement of water and solutes out of the glomerular capillaries, while proteins and blood cells remain. This increases the concentration of solutes (thus decreasing the concentration of water) in the glomerular capillaries and therefore promotes the return of water to the glomerular capillaries by osmosis. The capsular hydrostatic pressure inhibits filtration. This pressure develops as water collects in the glomerular capsule. The more water in the capsule, the greater the pressure....
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This note was uploaded on 11/10/2011 for the course PT 101 taught by Professor Staff during the Spring '10 term at Texas State.

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