Vascular - Physiology & fluid dynamics - Ch 2

what is stroke volume

amount of blood ejected from left ventricle

what are three types of energy in cirulatory system

potential, kinetic, hydrostatic/gravitational

where is potential energy of circulatory system (pressure energy)

heart

where is kinetic energy of circulatory system

pump of blood/velocity

what does pumping action of heart do

causes large pressure gradient between arteries and veins (high pressure from high volume from heart)

what is energy

power to produce motion, overcome resistance, effect changes

what is the largest contributor to resistance

radius of vessel - raised to 4th power 

what is resistance formula

8(viscosity)(length) divided by (pie)(radius^4)

what is volume flow formula (Poiseuille’s law)

(prox pressure - dist pressure)(pie)(radius^4) divided by (8)(viscosity)(length)

if velocity is high, pressure is __

low

when would kinetic energy increase

after stenosis, during exercise = high velocity

which part of heart is considered “0” hydrostatic pressure

right atrium

what is laminar flow made up from

layers of fluid particles moving against each other

what is biggest reason for energy loss

heat (a form of viscous energy loss)

parabolic flow shape

bullet

what does Poiseullie’s Law describe

relationship of pressure, volume flow, and resistance - how much fluid is moving through?

what does Bernoulli’s Principle explain

uses law of conservation of energy to explain how pressure and velocity are inversely related

what happens to pressure and velocity at the exit of a stenosis

pressure increases, velocity decreases

what is Reynold’s number

unitless number that describes turbulant flow

what affects reynold’s number

velocity, viscosity, density, radius

what reynold’s number is considered turbulant and laminar flow

>2000 ; <1500

what are flow separations caused by

differences of pressure in two points of vessel (color vs no color in systole and diastole)

what type of flow does a fasting SMA have

high resistance

what do high pulsatility arteries feed (triphasic)

high resistant, peripherals (SFA, pop)

what might pain when walking indicate

collaterol effect of arterial disease, collaterols can’t keep up to demand

what waveform will a cool, vasoconstricted extremity have

pulsatile

what % is a significant stenosis

cross section reduction is 75%

what is radius of a cross section diameter reduction of 75%

50%

what is radius of a cross section diameter reduction of 90%

70%

what is radius of a cross section diameter reduction of 99%

90%

how do eddy currents and vortices affect energy

creates energy loss via heat due to currents working against viscosity of blood