Term
| AV shunt important for ___ regulation, also provides ___ ___ pathway from __ to ___. |
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Definition
- temperature
- arteriole
- venules |
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Term
| Even though a capillary is only one endothelial cell thick, the pressure is about 20-25 mm Hg. It can get this high b/c the __ is a function of the __ and __, and since the radius is so small, a higher pressure can be achieved. |
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Definition
- tension
- pressure
- radius |
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Term
| Wall tension acts to prevent a rupture along the theortecal long slit of the vessel. |
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Definition
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Term
| __ ___ is a potent vasodilator produced in response to shear stress. |
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Definition
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Term
| FASTER BLOOD FLOW, MORE SHEAR STRESS, MORE NITRIC OXIDE PRODUCED, THIS A FEED FORWARD MECHANISM: SO IF BLOOD FLOW INCREASES IN RESPONSE TO ANOTHER VARIABLE> INCRASE SHEAR STRESS> INCREASED NO |
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Definition
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Term
| shear stress also causes dilation by making : |
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Definition
| prostaglandins or prostocyclins PGI2 |
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Term
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Definition
Released in response to shear stress and ?
Inhibits platelet adherence to endothelium
Relaxes vascular smooth muscle |
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Term
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Definition
Released in response to shear stress, acetylcholine, ATP, bradykinin, histamine, hypoxia
Relaxes vascular smooth muscle |
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Term
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Definition
- potent vasoconstrictor
- made by endothelium |
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Term
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Definition
Lipid-soluble molecules (such as O2 & CO2) readily pass through the lipid component of endothelial cell membranes.
Water readily crosses the capillary wall, through the cell membranes and fenestrations.
Water-soluble molecules and ions must diffuse through the pores (water-filled pathways) in the capillary wall at the junctions between cells.
Large molecules cross the capillary wall by pinocytosis. |
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Term
| capillary permeabiiity of a substance varies from tissue to tissue, but is not physiologically regulated. |
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Definition
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Term
| Capillary surface area is physiologically regulated by ___ and ___ ___ constriction or dilation. |
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Definition
- arterioloar
- precapillary sphincter |
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Term
| List the four pressures that determine filtration or absorption: |
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Definition
1) Pc = capillary hydrostatic pressure
2) Pi = interstitial fluid hydrostatic pressure
3) Πp = plasma oncotic pressure
4) Πi = interstitial fluid oncotic pressure |
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Term
| The capillary reflection coefficient in the Starling equation relates how much of the ___ ___ ___ ___ will be expressed across the ___ wall. |
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Definition
- potential net oncotic pressure
- capillary |
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Term
| If the capillary wall is impermeable to sources of oncotic pressure (plasma proteins), then the coefficient is: |
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Definition
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Term
| As the capillary wall becomes more permeable the coefficient ___. |
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Definition
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Term
| coefficient varies from 0-1. |
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Definition
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Term
| LOOK AT SLIDE 18 AND KNOW HOW TO DO THIS |
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Definition
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Term
POSITIVE NUMBER= NET FILTRATION
NEGATIVE NUMBER= ABSORPTION
WITH POSTIVE NUMBER, EDEMA WILL OCCUR DEPENDING ON LYMPHATICS |
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Definition
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Term
| As flltration increases, the lymph flow will increase to match filtration, but to do this it needs an increased tissue pressure. |
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Definition
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Term
| So excessive filtration, edema is occuring, to save itself> increased arteriole constriction and sphincter close> less pressure downstream> less filtration, then in interstitial space you have increased pressure b/c of edema so lymphatics compensate |
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Definition
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Term
| 6 Factors of the margin of safety that help prevent edema: |
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Definition
1. Myogenic compensation:
- increased precapillary resistance
- decreased capillary surface area
2. Interstitial compensation:
- rise in interstitial fluid pressure
- dilution of interstitial proteins
3. Lymphatic compensation
- acceleration of fluid removal
- washout of interstitial proteins |
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