Vasculature 2 Flashcards
The following lipid soluble substances can diffuse through capillary endothelium
dissolved oxygen
carbon dioxide
fatty acids
hormones
lipid insoluble substances diffuse through capillary pores
electrolytes
glucose
amino acids
Transcytosis
how plasma proteins move through capillary walls
Ficks law
Rate of diffusion=
=DA([S]c-[S]i)/delta X
- D=diffusion coefficient
- A=Area available for diffusion
- delta X= Distance over which diffusion occurs
- Sc-Si= concentration gradient
How does D change with increased lipid solubility and decreased molecular size
increased lipid solubility= increased diffusion coefficient
decreased molecular size=increased diffusion coefficient
Increase tendency for filtration can occur from
increase hydrostatic difference
decrease oncotic pressure difference
Increase permeability of wall to water
Transcapillary water flux
= Kfx [(Pc-Pi)-(piec-piei)]= +1
Lymphatic vessels prevent
interstitial fluid from accumulating
Lymph moves by?
bulk flow
- one way valves
- SM in some lymphs
edema results from?
excessive filtration of fluid from capillaries
reduced lymphatic function
3 factors help limit the degree of interstitial fluid(IF) build-up
increased IF pressure opposes capillary filtration
increased IF promotes increased lymph flow
decreased interstitial fluid protein reduces capillary filtration
Common causes of edema
increased venous pressure (heart failure, tight extremity dressing)
decreased plasma protein concentrations (reduced liver protein production, protein losing diseases)
Lymphatic vessel obstruction (cancer, inflammation)
