Lwcture 20 Part 2

Question 1

Volumetric flow rate for a short segment is

Answer 1

Constant

Usually talking about a stenosis

Question 2

Continuity rule equation

Answer 2

Q= Vavg x A

Q- volumetric flow rate (mL/s)
Vavg - average velocity (cm/s)
A - cross- sectional area (cm^2)

Question 3

A decrease in area of tube means

Answer 3

There must be an increase in velocity to keep the same amount of blood going through

Question 4

Initally as A decreases, V goes _______, to keep Q _______

Answer 4

Up

Constant

Question 5

At A= 75%

Answer 5

The vessel resistance increases

Q starts to go down, eventually becoming 0 — occlusion

V keeps going up to compensate decrease in A, but eventually goes down as well at near occlusion

Question 6

Q at 0 is called

Answer 6

Occlusion

Question 7

If we can figure out how fast the blood is going at a stenosis then

Answer 7

We can figure out how much it is stenosed

The speed will determine the severity of the disease

Question 8

Sound produced by stenosis

Answer 8

Brute

Question 9

If radius is decrease by 2x then area is

Answer 9

Decreased 4 times

Question 10

If radius is decreased 2x then velocity will

Answer 10

4x

Question 11

Difference between the two equations for Q

Answer 11

Q=Vavg x A —> short segments (stenosis)

Q=P(pi)(d^4)/128Ln —> long straight tube

Question 12

Bernoulli effect

Answer 12

Decrease in pressure in regions of high flow speed (at stenosis)

Velocity reciprical of pressure

Question 13

Before a stenosis the pressure

Answer 13

Goes up to push blood through stenosis

Question 14

At stenosis pressure goes

Answer 14

Down to maintain energy

Pressure energy —> flow energy

Question 15

After stenosis

Answer 15

Flow energy becomes pressure energy