10 Capillaries Flashcards
What is Fick’s Law?
(SA x conc difference) / membrane thickness
what does having more capillaries do?
increases SA
decreases diffusion distance
increases rate of diffusion
What will the distribution of capillaries be like in tissues of high metabolic function?
high C:F
How can the concentration gradient be increased?
increasing blood flow
what would oedema do to rate of diffusion?
decrease it by increasing diffusion distance
What would anaemia do to rate of diffusion?
decrease it by increasing diffusion distance
What would atherosclerosis do to rate of diffusion?
reduces flow and hence concentration gradient, decreasing rate of dissusion
What is the capillary hydrostatic pressure at the arteriolar end?
35 mmHg
What is the capillary hydrostatic pressure at the venous end?
15 mmHg
What 2 forces favour reabsorption?
interstitial hydrostatic pressure (0mmHg)
capillary oncotic pressure (25mmHg due to pp conc)
What 2 forces favour filtration?
capillaryu hydrostatic pressure
interstitial oncotic pressure
What is the net filtration pressure?
(Pcap + interstitial oncotic pressure) - (Pi + capillary oncotic pressure)
what is the filtration pressure?
+10mmHg
What is the reabsorption pressure?
-10mmHg
what is the net oncotic pressure?
capillary oncotic pressure - interstitial oncotic pressure
