| Question |
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| Answer |
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| Microcirculation |
portion of teh systemic and pulmonary circulations adapted for the exchange of gases, nutrients and waste products |
| Anatamy of Micro circulation |
Metarterioles -> Precapillary sphincter region -> Capillaries -> A-V Shunt -> Venules |
| Precapillary sphincter |
smooth muscle cell |
| A-V Shunts |
Arterial - Venous Shunt
Blood from artery shunts blood to venous side without passing thru the capillaries |
| Capillary Anatomy |
7-10micron diamater
Single layer endothelium and basement membrane |
| Low Continuous Exchange |
Muscle, nerve adipose |
| High Continuous Exchange |
Lymph and thymus |
| Open Fenestrated |
Renal Glomeruli |
| Closed Fenestrated |
Endocrines adn intestinal villi |
| Discontinuous |
liver, bone marrow, spleen |
| Neural Control of peripheral circulation |
Sympathetic Alpha-adernergic vasoconstriction |
| Sympathetic Alpha adernergic vasoconstriction work on |
metarterioles
arteriols
some Beta 2-adernergic vasodilation |
| Local control of periphery |
local metabolic control of precapillary sphincter opening and closing; AUTOREGULATION |
| Regulation of microvascular resistance |
Myogenic regulation
activer hyperemia |
| Mygenic regulation |
increased pressure causes active relaxation
relaxation causes active contraction
prevents edema with sudden BP increase
assists with organ AUTOREGULATION |
| Active hyeremia |
increased blood flow with increased metabolism |
| Products that relax sphincter smooth muscle |
H+
O2
CO2 |
| Adenosine |
potent dilator and especially important for the heart and brain |
| Increased pressure causes _____________ |
active relaxation |
| Relaxation causes ___________ |
active contraction |
| Encothelial cell shear causes synthesis of __ |
NO |
| NO inhibits _____________ |
smooth muscle contraction |
| NO activates |
Guanylate cyclase |
| guanylate cyclase makes |
cGMP
cyclic Guanosine Monophosphate |
| cGMP inhibits |
smooth muscle contraction |
| NO released from endothelial cells by ____________ and _____________ |
endothelial NO synthase and arginine |
| Fick's Law of Perfusion |
J=PS(dc/dx) |
| PS |
permeability and surface area |
| dc/dx |
concentration difference between blood and interstitium |
| Permeability and surface area depend on |
-temp, molecular radius and viscocity
-% of capillaries open
-type of endothelium |
| Types of Limited Transport |
Flow Limited
Rate Limited |
| Flow Limited transport |
diffusion is fast and transport is only changed by the rate of blood perfusing a tissue |
| Rate Limited Transport |
Larger molecules have difficulty moving thru pores and thus diffusion is rate limiting |
| Pneumonia |
Oxygen and CO2 are normally flow limited
Fluid adds diffusion distance and viscocity
diffusion of gases shifts from flow-limited to diffusion-limited |
| Water movement depends on (2) |
pressure differences across teh capillary membrane
Hydrolic conductivity and area of diffusion |
| Starling-Landis Equation |
equation for movement of water |
| Capillary filtration Coefficient |
Water vol/ml/min per 1 mmHg P change / 100 g tissue
Compares how leaky different tissues are for water |
| Capillary filtration coefficent changes with _____________- |
permeability of each capillary and which cross section is perfused |
| Burns |
destroys capillary integrity so permeability increases, plus increase albumen leaks out |
| CHP |
Capillary Hydrostatic Pressure
BP of capillary |
| THP |
Tissue hydrostatic Pressure
Fluid pressure associated between fluid between the cells |
| TOP |
Tissue Oncotic Pressure
Force of water trying to dilute the protein concentration of the interstital fluid |
| COP |
Capillary Oncotic Pressure
Force of water trying to dilute the protein concentration of interstitial side |
| Two outward pressures driving water |
Capillary Hydrostatic Pressure
Tissue Oncotic Pressure |
| Two inward pressures driving water |
Capillary Oncotic Pressure
Tissue Hydrostatic Pressure |
| Water Pressure Equilibrium |
CHP + TOP = COP + THP
THP ~ TOP ~ 0 mmHg |
| California Gangster Rule |
CHP=COP |
| Increased capillary hydrostatic Pressure |
CHP > COP
heart failure
DVT |
| Low Plasma Proteins |
COP < CHP
Quashiorkor
Severe burns
nephrosis |
| Lymphedema |
CHP+TOP > COP
Sinus infection plugs up lymph drainage |
| Quashiokor |
protein malnutrition |
Poultry
