Hemodynamics

Question 1

Hemodynamics is the study of what?

Answer 1

blood moving through the circulatory system.

Question 2

What is flow?

Answer 2

aka: volume flow rate

indicates the volume of blood moving during a particular time.

Question 3

Flow answers what question?

Answer 3

How much

Question 4

Flow answers what question?

Answer 4

How much

Question 5

what does velocity indicate?

Answer 5

the speed of moving fluid from one location to another.

Question 6

Velocity answers what question?

Answer 6

how fast

Question 7

What are the 3 basic forms of flow

Answer 7

1. pulsatile
2. phasic
3. steady

Question 8

what is pulsatile flow?

Answer 8

blood flow with a variable velocity.

As a result of cardiac contraction

Question 9

What is phasic flow?

Answer 9

as a result of respiration

Question 10

Steady flow is what?

Answer 10

fluid moving at a constant speed.

Question 11

What are the 2 forms of laminar flow?

Answer 11

1. Plug flow
2. parabolic flow

Question 12

What is plug flow

Answer 12

all layers of blood travel at the same velocity.

Often seen at the beginning of vessels.

Question 13

what is parabolic flow?

Answer 13

velocity is highest in the center of the lumen.

Question 14

What does the reynolds’s number predict?

Answer 14

whether flow is laminar t or turbulent.

Question 15

what reynolds’s number predicts turbulent flow?

Answer 15

<2000

Question 16

turbulent flow is often characterized by what?

Answer 16

chaotic flow patterns in many different directions and speed.

Question 17

What is a sound associated with turbulence?

Answer 17

murmur or bruit

Question 18

What is a vibration associated with turbulence?

Answer 18

A thrill

Question 19

blood moving from regions of higher energy to lower is called what?

Answer 19

an energy gradient

Question 20

What are the three forms of energy?

Answer 20

1. Kinetic
2. Pressure
3. gravitational

Question 21

kinetic energy is associated with what?

Answer 21

a moving object

Question 22

Pressure energy is a form of what?

Answer 22

stored or potential energy

Question 23

Potential energy has the ability to do what?

Answer 23

Perform work

Question 24

gravitational energy is associated with what?

Answer 24

any elevated object

Question 25

What are the 3 ways energy is lost through circulation?

Answer 25

1. viscous loss 2. frictional loss 3. inertial loss

Question 26

what is viscous energy loss?

Answer 26

has to do with the thickness of blood

Question 27

In what 3 ways does inertia energy loss happen?

Answer 27

1. pulsatile flow 2. phasic flow 3. velocity changes at a stenosis

Question 28

What are 5 effects of a stenosis?

Answer 28

1. change in flow direction 2. increased velocity as vessel narrows 3 turbulence downstream from the stenosis 4. pressure gradient across the stenosis 5. loss of pulsatility

Question 29

Bernoulli describes the relationship between what?

Answer 29

between velocity and pressure in a moving fluid

Question 30

What is the law of conservation of energy

Answer 30

energy is neither created nor destroyed. States that pressure energy is lowest wherever the kinetic energy is the highest, at the narrowest part of the lumen.

Question 31

What is the formula for pressure gradient?

Answer 31

Pressure gradient=flow x resistance

Question 32

What is the relationship between pressure gradient and flow/resistance?

Answer 32

Directly. When Pressure gradient increases, flow and resistance increases.

Question 33

What is hydrostatic pressure?

Answer 33

pressure related to the weight of blood pressing on a vessel.

Question 34

What is the hydrostatic pressure of a supine individual?

Answer 34

0

Question 35

what is the formula for measured pressure?

Answer 35

Measured pressure= circulatory pressure + hydrostatic presure.

Question 36

What is the arterial pressure measured in the toe of the upright patient?

Answer 36

240mmHG Hydrostatic pressure= 100mmHG Pressure generated by the heart is 140 mmHG 100+140=240mmHG

Question 37

What is the arterial pressure measured at the standing patients upper arm?

Answer 37

140mmHG Hydrostatic pressure = 0mmHG Pressure generated by the heart = 140mmHG 0+140=140mmHG

Question 38

What is the arterial pressure measured at the finger when the patient fully extends an arm toward the sky?

Answer 38

90mmHG Hydrostatic pressure= -50mmHG Pressure generated by the heart= 140mmHG -50+140=90mmHG

Question 39

Normally, what happens to venous flow in the legs during inspiration?

Answer 39

Venous flow in the legs decreases.

Question 40

What is the primary reason blood moves from on location to another?

Answer 40

energy gradient

Question 41

Which of the following causes the greatest amount of inertial energy loss? pulsatile flow flow through a stenosis phasic flow steady flow parabolic flow

Answer 41

Flow through a stenosis flow through a stenosis causes the greatest velocity changes and greatest inertial loss.

Question 42

What happens to the diaphragm when an individual breathes in?

Answer 42

diaphragm descends into the abdomen

Question 43

What happens to venous return to the heart when an individual inhales?

Answer 43

venous return to the heart increases.

Question 44

What happens to venous flow in the legs during inhalation?

Answer 44

Venous flow in the legs decreases

Question 45

What happens to the diaphragm when an individual breathes out?

Answer 45

It moves up into the chest cavity

Question 46

What happens to venous return to the heart during exhalation?

Answer 46

Venous return to the heart decreases.