Blood flow Flashcards
1
Q
What is darcys law of laminar flow?
A
Perfusion = pressure difference/Resistance
2
Q
What does pouselles law relate to?
A
Resistance
3
Q
What influences resistance?
A
Vessel radius
Length of vessel
Viscosity
4
Q
What is the no slip condition and what does it do?
A
Outer layer of blood doesnt move
Increases resistance
5
Q
In what vessels is viscosity least?
A
Small
6
Q
Why is viscosity least in small vessels?
A
Fahreus lindqvist effect
- Axial streaming - migrate to middle
- Bolus flow - take up whole vessel
7
Q
Why is viscosity less at high flow?
A
Sheer thinning - RBS move indendently and not in clumps
8
Q
How do you measure blood flow?
3 techniques
A
Tissue clearance via radioactive substance
plethysmography - block venous and measure swelling from arterial
Ficks principle - measure flow through and organ by looking at constituents
