PHSI 208 Lecture 43: M16 Renal System 1-2
Document Summary
The renal corpuscle = glomerulus + bowman"s capsule. Triple filtration barrier: capillary endothelial cells fenestrated, basal lamina extracellular matrix. Is negatively charged, which prevents plasma proteins from going through (as it is also negatively charged: podocyte endfeet forms filtration slits. Three pressures govern filtration from glomerular capillaries into the renal tubules. Hydrostatic pressure of blood in the glomerular capillaries favors filtration (~55 mmhg) Colloid osmotic (oncotic) pressure of the blood is the pressure gradient due to the presence of plasma proteins and opposes filtration (~30 mmhg) Bowman"s capsule hydrostatic pressure (fluid pressure) opposes filtration (~15 mmhg); you have to move that fluid forward for more filtration to occur. Net filtration pressure = ph (hydrostatic pressure in blood) (osmotic pressure) pfluid (bc hydrostatic pres. ) = 55 30 15 = 10 mmhg. Glomerular filtration rate (gfr) = the volume of fluid that filters from the glomerular capillaries into the bowman"s capsules per unit time.
