Circulation: Hemodynamics of Blood Flow Flashcards
what 2 laws describe circulation?
Ohm’s Law & Poiseuille’s Law
what is venous blood pressure?
0 - 4mmHg
venous blood pressure is equal to ____
right atrial pressure
what type of blood vessel has the largest cross sectional area?
capillaries
what blood vessel has the smallest cross sectional area?
aorta
what blood vessel has the fastest velocity?
aorta
what blood vessel has the slowest velocity?
capillaries
can you hear blood flow?
NO
what type of flow do RBCs travel in?
laminar flow
does blood pressure vary across large arteries?
NO
what type of blood vessels have variable pressures?
arterioles
the heart acts as a ____ from a … system to a … system
pump
0 pressure vein system
high pressure arterial system
what is the overall equation for Ohm’s law?
flow = change in P/resistance
what is flow equivalent to?
cardiac output
in Ohm’s law, where does change in pressure occur
between artery and vein
what is another way to write the Ohm’s law equation?
CO = (mean arterial P - central venous P)/total peripheral resistance
what is another term for central venous pressure?
right arterial pressure
what is Poiseuille’s Law?
- flow is proportional to the radius or diameter to the 4th power
- pressure is constant to calculate impact of radius on flow
vasoconstriction causes a decrease in…
- flow
- hydrostatic P; BP
- blood volume
- conductance
(FPVC)
vasoconstriction causes an increase in…
resistance (R)
what factors increase resistance?
- longer vessel
- blood viscosity
- decreased radius (most impact)
vasodilation causes a decrease in…
resistance (R)
vasodilation causes an increase in…
- flow
- hydrostatic P; BP
- blood volume
- conductance
(F,P,V,C)
what is compliance?
ability of a vessel to expand when more blood flow enters in
do veins or arteries have more compliance? why?
veins
larger lumen per size of vessel
what condition can decrease the compliance of arteries?
atherosclerosis
atherosclerosis would cause an increase in…
resistance
what segment of the circulatory system has the highest velocity?
aorta (large diameter)
what vessels have the highest total cross-sectional area in the circulatory system?
capillaries
the tendency for turbulent flow is greatest in the ____
aorta
