Phys Lecture 6: Microcirculation Flashcards
How is blood flow regulated through the capillaries?
sphincters
How does CO2 and O2 pass thru the capillary wall?
diffusion
How does water and small solutes pass thru the capillary wall?
clefts
How do plasma proteins pass thru capillary wall?
fenestrations in wall
How do large molecules pass thru capillary wall?
endocytosis
What does a reflection coefficient close to 1 mean?
that molecules is impermeable to the capillary endothelium
What does a permeability coefficient of 1 mean?
that the molecule is permeable to the capillary wall
How would the reflection coef change in an inflammatory state such as a burn?
would decrease (<1) *proteins are allowed to flow through
What is the starling equation?
flow = Kf x [(HPc-HPi) - (OPc-OPi)]
What are the positive pressures?
those that favor filtration:
-high HPc and low OPc
What are the negative pressures?
those the favor abs into capillary:
-High OPc an low HPc ??
In the arterial side of capillaries, there is normally net ____
filtration/movement of fluid into interstitial space
In the venous side of capillaries, there is normally net ____
absorption/movement of fluid into capillaries
Describe the starling forces along the length of capillaries and how that effects blood flow…
OP is constant but HP is higher at arterial end then venous = net pressure is higher at arterial end then venous… blood flows from high to low pressure = blood always flows from arterial to venous
**also the filtration pressure > abs pressure = more net filtration than abs
What is the relationship between Kf and R?
Kf = 1/R
* inc R -> dec Kf
