Capillaries II Flashcards
Fluid exchange
How is hydrostatic pressure exerted? [2 marks]
- Fluid moves across membrane to interstitial space
- Due to blood flow
How is osmotic pressure exerted? [2 marks]
- Fluid moves into capillaries
- Due to plasma proteins
What is Πp and Πi? [2 marks]
Πp = osmotic pressure due to plasma proteins Πi = osmotic pressure due to interstitial proteins
What is Pc and Pi? [2 marks]
Pc = hydrostatic pressure due to capillary blood pressure Pi = hydrostatic pressure due to capillary blood
What does Jv mean? [1 mark]
Movement of fluid (flux)
What does Lp mean? [1 mark]
Hydraulic conductance of endothelium i.e. how leaky it is to fluid
What does σ mean? [2 marks]
Reflection coefficient i.e. fraction of osmotic pressure that is exerted
σ = 1 = reflected
σ = 0 = leaks out
What are Lp and A in normal conditions? [1 mark]
CONSTANT
What happens to hydrostatic pressure as you go down a capillary? [1 mark]
Decreases
What happens to osmotic pressure as you go down a capillary? [1 mark]
Nothing
What can excess filtration be caused by? [2 marks]
- Decreased osmotic pressure
- Increased hydrostatic pressure
What does control of extracellular fluid balance depend on? [3 marks]
- Capillary filtration
- Capillary reabsorption
- Lymphatic system
Which Starling factors determine change in fluid balance? [3 marks]
- Circulation
- Interstitial fluid
- Lymphatic system
What happens to osmotic pressure in hypovolemia? [1 mark]
Nothing
What happens to hydrostatic pressure in hypovolemia? [1 mark]
Decreases
