生理学的概念及生命活动的特征 (30).ppt

PhysiologyFormation and Excretion of UrineThe glomerular filtration membraneABCIntroductionFunction of Glomerular FiltrationThe pressure of the glomerular filtrationGlomerular filtration rate and filtration fraction Glomerular Filtration When blood flows through the glomerulus,the water and small molecular substances in plasma enter the Bowmans capsule through the glomerular filtration membrane to form prourine.Glomerular Filtration1TOPICThe glomerular filtration membrane1.The glomerular filtration membrane Endothelium Basement membrane Epithelium(podocytes)1.1 Composition of the glomerular filtration membraneOrganization of filtration membrane1.The glomerular filtration membrane Molecular radius Electrical charge1.2 Permeability of the glomerular filtration membrane2TOPICThe pressure of the glomerular filtration The hydrostatic pressure inside the glomerular capillaries(glomerular hydrostatic pressure)The hydrostatic pressure in Bowmans capsule The colloid osmotic pressure of the glomerular capillary plasma proteins The colloid osmotic pressure of the proteins in Bowmans capsule2.The pressure of the glomerular filtrationNet filtration pressureGlomerular hydrostatic pressureBowmans capsule pressureGlomerular colloid osmotic pressure2.The pressure of the glomerular filtrationNet filtration pressure=45-(25+10)=10 mmHg0Ultrafiltration generationNet filtration pressure=45-(35+10)=0 mmHg=0Filtration equilibrium3TOPICGlomerular filtration rate and filtration fraction3.Glomerular filtration rate and filtration fractionThe amount of ultrafiltration produced by two kidneys per unit time(per minute).3.1 Glomerular filtration rate(GFR)About 125 ml of water and dissolved substances are filtered out of the blood per minute.GFR for the whole body is normally about 125 mL/min.The GFR per hour is:125 mL/min 60 min/hr=7500 mL/hr.The GFR per day is:7500 mL/hr 24 hr/d=180000 mL/d or 180 L/d.3.Glomerular filtration rate and filtration fraction3.2 Filtration fraction(FF)Nearly 20%of the plasma flowing through the kidney is filtered through the glomerular capillaries.Filtration fraction=GFR/Renal plasma flow.FF is normally about 19%.Thank you