Hemodynamics Flashcards
circulatory system is
closed
CO =
5 L/min
pressure gradient is created by
heart
RA pressure =
0 mmHg
flow occurs from ___ to ___ pressure
high to low
circulatory system is comprised of
heart - arteries- arterioles- capillaries - venules - veins- back to heart
flow is created by
pressure gradient
capacitance vessels
veins
blood makeup
plasma = water, protein
RBC, WBC, platelets
hematocrit
% of RBC in blood
flow regulating mechanisms
CO, cardiac function, tone + elasticity of vessels, interconnecting arterioles
principle point of resistance
interconnecting arterioles
regulators
interconnecting arterioles
vasomotor tone
constriction, dilation of vessels
Starlings law
stretch - > force of contraction of ventricles
HR is affected by
baroreceptors, chemoreceptors, exercise
Windkessel effect
elasticity of vessel, wall compliance, tone
reflection of wave back up vessel wall, creates dicrotic notch
arterial pulse pressure wave
pressure wave is propagated throughout arterial tree with each contraction of heart.
pressure wave velocity increases as it moves into smaller, stiffer peripheral arterioles
times it takes for pressure wave to travel from heart to foot
250 ms
arterial pulse pressure wave occurs in
vessel wall, independent of blood
volume flow
volume of blood passing a point per unit of time
adult blood flow rate
5 L/min
Q =
(A) X (TAV)
Continuity rule
volume in closed system must stay constant. Blood volume is not lost or created (conservation of matter)
Continuity rule in case of stenosis
since the same volume of blood must pass, but the area is smaller, the velocity therefore must increase
Continuity equation
A1V1 = A2V2
if area is halved, then velocity is
doubled
a change in area affects
pressure and flow
density of blood
1.05 g/mL
viscosity of blood
0.035 poise