Arterial Physiology (Lecture 2) Flashcards
Blood will move from an area of _____ energy to an area of _____ energy.
high (pressure)
low (pressure)
What does the Bernoulli principle state?
When a fluid flows without change in velocity from one point to another, the total energy content remains constant, providing no frictional losses
What is more viscous - fluid or honey?
Honey
Velocity and flow are related by which equation?
V = Q/A
The total area occupied by the capillaries is how much greater than the aorta?
600 times greater
If blood flow remains constant, velocity ____ when the area decreases, and vice versa.
increases
What is the equation for Poiseuille’s Law?
Q= π (P1−P2) r^4 / 8ηl
What has the biggest impact on flow?
Radius
What is the most important determinant of blood flow?
Radius
A decrease in the radius of a vessel by half will increase the energy losses by a factor of… ?
16
A doubling in the length of a vessel will yield an increase the energy losses by a factor of… ?
2
What is the equation for Ohm Law?
R = △P / Q
When you combine Poiseuille Law and Ohm law, what equation do you get?
R = 8ηl / π r^4
For resistances in series (one vessel after another), what is the equation?
Rₜ = R1 + R2 + R3
For resistances in parallel (vessels side by side), what is the equation?
1/Rₜ = 1/R1 + 1/R2 + 1/R3
The more parallel elements in a network, how will this affect the resistance of the network?
Lower overall resistance
A low resistance flow profile has what type of characteristic flow throughout the cardiac cycle?
Antegrade
What type of flow does a high resistance flow profile display?
Both antegrade and retrograde
How can some high resistance tissue beds be changed into low-resistance beds?
Exercise
How can some low resistance tissue beds be changed into high-resistance beds?
Eating
What is ‘Re’?
The Reynolds Number; directly proportional to the velocity of blood, density of blood, and radius of blood vessel.
Flow will be laminar with an Re below what?
Re below 2000
Flow will be turbulent with an Re above what?
Re above 2000
What is Capacitance?
The ability of a vessel to store energy
Stiffer walls of the heart indicate what for the pressure in both systole and diastole?
In systole, greater pressure
In diastole, reduced pressure
If interstitial O2 levels fall, which vessel dilates?
arterioles
What is the difference between Fibrous plaque and Complicated plaque?
Fibrous - smooth, composed of smooth muscle and fibrous tissue and lacks calcs
Complicated - irregular surface, loss of the normal endothelium and calcs present
Where does Atherosclerosis typically develop?
Branch points and bifurcation
A critical stenosis is defined at which percentage?
Cross sectional area reduced by 75%
A stenosis in which area can become critical with a less severe degree of narrowing?
high flow/ low resistance
