HUMAN PHYSIOLOGY PPT Presentation by Chen Qi Chapter 8 Urinary Physiology Physiological Department of Medical College, Yangzhou University
General introductionofkidney1Renal Functions1.1 urine formationexcrete wastes ,maintain H,O, ions, acid-base balance1.2 secret hormones : renin, 1,25-vitaminD3, erythropoietinPPTPresentationbyChenQi,YangzhouUniversity
2.Renal structure2.2 Cortical nephron and juxtamedullary nephronconcentration and dilution of urineurine formation2.3 Juxtaglomerular apparatus (JGA) juxtaglomerular cells : secret reninmacular densa : regulate renin secretionPPTPresentationbyChenQi,YangzhouUniversity
3. Renal blood flow3.1Characteristics3.2Regulation1)Autoregulationdefinition:Bp(80-180mmHg)→RPFconstant② significance :under physiological condition, keep RPF and thenGFR constant, to make sure wastes canbeexcreted?mechanismsPPTPresentationbyChenQi,YangzhouUniversity
2) nervous-hormonal regulatior①Bp<80mmHg→urineIlsympathetic nerves @ ; NE, E, angiotensinII 个② significance : under exercise or severe hemorrhage, spares alarge amount of blood for active or important organsPPTPresentationbyChenQi,YangzhouUniversity
Processesof urineformation1. Glomerular filtration1.1 Glomerular filtration rate (GFR)1) definition : the volume of the filtrate by two kidneys (125ml/min)2)filtration fraction (FF) : GFR/RPF =19%renal plasma flow (660ml/min)PPTPresentationbyChenQiYangzhouUniversity
1.2 Filtration mechanism1)effective filtration pressure (EFP)glomerularcapillary'spressure-PccBowman's capsule's pressure-Prccolloid osmotic pressure in glomeruli-ccEFP=PGC-(PBC+元GC)PPTPresentationbyChenQi,YangzhouUniversity
2)Permeabilityendothelialcellsofglomerularcapillary size of moleculesbasementmembraneepithelial lining of Bowman's capsule (podocytes) 8nm (cannot)4-8nm→ albumin, red cells2)electrical charge of molecules (sialoproteins“"+"> neutral molecule>“_"PPTPresentationbyChenQi,YangzhouUniversity
1.3 Affecting factorsEFP PGc : terminal stage of hypertension urine PBc 个 : kidney stones → urine J元G ↓ : fast and large intravenous infusion urine ↑②renalplasmaflowpermeabilityPPTPresentationbyChenQi,YangzhouUniversityDEFP
2. Tubular reabsorption1) H,O : 99% ; osmosisinproximal tubule : 65%in thin descending limb :20%in ascending limb= 0in distal tubules and collecting ducts >regulatedPPTPresentationbyChenQi,YangzhouUniversity