| Question |
Answer |
| 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 |
Ch.18 LTI-MA 509
