Presentation on theme: "The Microcirculation Figure 16-1; Guyton and Hall."— Presentation transcript:
1 The MicrocirculationFigure 16-1; Guyton and Hall
2 Structure of Capillary Wall Figure 16-2; Guyton and Hall
3 Interstitium and Interstitial Fluid Figure 16-4; Guyton and Hall
4 Determinants of Net Fluid Movement across Capillaries Figure 16-5; Guyton and HallCapillary hydrostatic pressure (Pc)-tends to force fluid outward through the capillary membrane.Interstitial fluid pressure (Pif)- opposes filtration when value is positive.
5 Determinants of Net Fluid Movement across Capillaries Figure 16-5; Guyton and HallPlasma colloid osmotic pressure ( c)- opposes filtration causing osmosis of water inward through the membraneInterstitial fluid colloid pressure ( if) promotes filtration by causing osmosis of fluid outward through the membraneNP = Pc - c - Pif + if
6 Plasma Proteins and Colloid Osmotic Pressure 75% of the total colloid osmotic pressure of plasma results from the presence of albumin and 25% is due to globulins.gm/dl p(mmHg)AlbuminGlobulinsFibrinogenTotal
7 Determinants of Net Fluid Movement Across Capillaries Figure 16-5; Guyton and HallFiltration rate = net filtration pressure (NFP) multiplied by the filtration coefficientFiltration coefficient (Kf) is a product of surface area times the hydraulic conductivity of membrane
8 Forces Causing Filtration at the Arteriole End of the Capillary mmHgForces tending to move fluid outward:Capillary pressure 30Negative interstitial free fluid pressure 3Interstitial fluid colloid osmotic pressure 8TOTAL OUTWARD FORCEForces tending to move fluid inward:Plasma colloid osmotic pressure 28TOTAL INWARD FORCESummation of forces:OutwardInwardNET OUTWARD FORCE
9 Forces Causing Reabsorption at the Venous End of the Capillary mmHgForces tending to move fluid inward:Plasma colloid osmotic pressure 28TOTAL INWARD FORCEForces tending to move fluid outward:Capillary pressure 10Negative interstitial free fluid pressureInterstitial fluid colloid osmotic pressureTOTAL OUTWARD FORCE 21Summation of forces:Outward 21Inward 28NET INWARD FORCE 7
10 Net Starling Forces in Capillaries mmHgMean forces tending to move fluid outward: Mean Capillary pressure 17.3 Negative interstitial free fluid pressure 3.0 Interstitial fluid colloid osmotic pressure 8.0 TOTAL OUTWARD FORCE 28.3 Mean force tending to move fluid inward: Plasma colloid osmotic pressure 28.0 TOTAL INWARD FORCE 28.0 Summation of mean forces: Outward 28.3 Inward 28.0 NET OUTWARD FORCE 0.3
11 Net Starling Forces in Capillaries Figure opener; Guyton and HallNet filtration pressure of .3 mmHg which causes a net filtration rate of 2ml/min for entire body.
12 Question Utilizing the data below, calculate the rate of net fluid movement across the capillary wall:Pressures (in mmHg)Plasma colloid osmotic = 20Capillary hydrostatic = 20Venous hydrostatic = 5Arterial = 80Interstitial hydrostatic = -5Interstitial colloid osmotic = 5Filtration coefficient = 10 ml/min/mmHga. 0 ml/min d. 100 ml/min (Reabsorption)b. 10 ml/min (Filtration) e. 10 ml/min (Reabsorption)c. 100 ml/min (Filtration)
14 Determinants of Lymph Flow The degree of activity of the lymphatic pumpsmooth muscle filaments in lymph vessel cause them to contractexternal compression also contributes to lymphatic pumpingFigure 16-11; Guyton and Hall
15 Determinants of Lymph Flow Interstitial fluid hydrostatic pressureLymph FlowFigure 16-9; Guyton and HallFigure 16-10; Guyton and Hall