Ch 18: Hemodynamics

Question 1

This indicates the volume of blood moving during a particular time.

Answer 1

flow (aka volume flow rate)

Question 2

Flow is measured in units of…

Answer 2

volume divided by time (L/min)

Question 3

This indicates the speed of a fluid moving from one location to another.

Answer 3

velocity

Question 4

Velocity is measured in units of…

Answer 4

distance divided by time (cm/s)

Question 5

Three basic forms of flow…

Answer 5

1. pulsatile
2. phasic
3. steady

Question 6

This kind of flow occurs when blood moves with a variable velocity as a result of cardiac contraction.

Answer 6

pulsatile flow

Question 7

This kind of flow commonly appears in the arterial circulation.

Answer 7

pulsatile flow

Question 8

This kind of flow occurs when a fluid moves with a variable velocity as a result of respiration.

Answer 8

phasic

Question 9

This kind of flow commonly appears in the venous circulation.

Answer 9

phasic

Question 10

This kind of flow occurs when a fluid moves at a constant speed.

Answer 10

steady

Question 11

This kind of flow is present in the venous circulation when individuals stop breathing for a moment.

Answer 11

steady

Question 12

This is when the flow streamlines are aligned and parallel.

Answer 12

laminar flow

Question 13

The word lamina means…

Answer 13

layer

Question 14

Laminar flow patterns are commonly found in __ physiologic states.

Answer 14

normal

Question 15

This flow occurs when all of the layers and blood cells travel at the same velocity.

Answer 15

plug flow

Question 16

This flow has a bullet-shaped profile with the highest velocity in the center of the lumen.

Answer 16

parabolic flow

Question 17

T/F? Laminar flow is silent flow.

Answer 17

true

Question 18

This predicts whether flow is laminar or turbulent.

Answer 18

Reynold’s number

Question 19

The Reynolds number for laminar flow is…

Answer 19

less than 1500.

Question 20

This flow is characterized by chaotic patterns in many different directions and at many speeds.

Answer 20

turbulent

Question 21

This is a small swirling rotational pattern appearing in turbulent flow.

Answer 21

eddy current or vortex

Question 22

T/F? Turbulent flow is often normal.

Answer 22

FALSE, pathologic

Question 23

This is tissue vibration associated with turbulence, a palpable murmur.

Answer 23

thrill

Question 24

The Reynolds number for turbulent flow is…

Answer 24

greater than 2000.

Question 25

Blood moves from regions of higher energy to lower energy. This is called...

Answer 25

energy gradient

Question 26

Three forms of energy associated with blood...

Answer 26

1. kinetic 2. pressure 3. gravitational

Question 27

The energy associates with a moving object is...

Answer 27

kinetic

Question 28

Kinetic energy is determined by two factors...

Answer 28

1. an object's mass | 2. the speed at which it moves

Question 29

The energy associated with stored or potential energy is...

Answer 29

pressure

Question 30

This energy is associated with any elevated object.

Answer 30

gravity

Question 31

T/F? Identical objects at the same height have the same gravitational energy.

Answer 31

true

Question 32

The three ways energy is lost in the circulation:

Answer 32

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

Question 33

This describes the thickness of a fluid.

Answer 33

viscosity

Question 34

Viscosity is measured in units of..

Answer 34

poise.

Question 35

This is the percentage of blood made up of red blood cells.

Answer 35

hematocrit

Question 36

This occurs when flow energy is converted to heat as one object rubs against another.

Answer 36

frictional energy loss

Question 37

This is related to the tendency of a fluid to resist changes in its velocity.

Answer 37

inertia

Question 38

Inertial energy loss in velocity changes in...

Answer 38

stenosis.

Question 39

Maximum velocity exists where the vessel is...

Answer 39

narrowest.

Question 40

This is a narrowing in the lumen of a vessel.

Answer 40

stenosis

Question 41

Stenosis __ the blood's direction.

Answer 41

changes

Question 42

Stenosis __ the blood's velocity.

Answer 42

increases

Question 43

This is turbulence downstream from the stenosis.

Answer 43

post-stenotic turbulence

Question 44

The pressure downstream from the stenosis is __ than the pressure upstream.

Answer 44

lower

Question 45

T/F? Flow stays pulsatile after passing througha stenosis.

Answer 45

FALSE, it becomes steady

Question 46

This describes the relationship between velocity and pressure in a moving fluid.

Answer 46

Bernoulli's principle

Question 47

This is derived from the principle of conservation of energy.

Answer 47

Bernoulli's principle

Question 48

flow x resistance =

Answer 48

pressure gradient

Question 49

Pressure gradient increases when either...

Answer 49

1. flow increases | 2. resistance increases

Question 50

Flow increases when either...

Answer 50

1. pressure gradient increases | 2. resistance decreases

Question 51

current x resistance =

Answer 51

voltage

Question 52

In an electrical system, pressure is called...

Answer 52

voltage.

Question 53

In an electrical system, flow is called...

Answer 53

current.

Question 54

Electrical resistance is measured in units of...

Answer 54

ohms.

Question 55

In the circulatory system, the resistance vessels are called...

Answer 55

arterioles.

Question 56

Veins are usually __ resistance vessels.

Answer 56

low

Question 57

When venous inflow increases, the cross-sectional shape of a vein...

Answer 57

changes from hourglass to oval to round.

Question 58

Normal veins increase flow with a __ increase in pressure.

Answer 58

small

Question 59

This is the pressure related to the weight of blood pressing on a vessel measured at a height above or below heart level.

Answer 59

hydrostatic pressure

Question 60

Hydrostatic pressure is reported in units of...

Answer 60

mmHg

Question 61

circulatory pressure + hydrostatic pressure =

Answer 61

measured pressure

Question 62

Hydrostatic pressure at the ankle

Answer 62

100 mmHg

Question 63

Hydrostatic pressure at the knee

Answer 63

75 mmHg

Question 64

Hydrostatic pressure at the waist

Answer 64

50 mmHg

Question 65

Hydrostatic pressure at the midchest

Answer 65

0 mmHg

Question 66

Hydrostatic pressure at the top of head

Answer 66

-30 mmHg

Question 67

Respiration affects venous flow for two reasons...

Answer 67

1. venous systems are low pressure | 2. it alters pressures in the thorax and abdomen

Question 68

During inspiration, the diaphragm moves...

Answer 68

downward.

Question 69

When the chest cavity expands, it creates __ pressure in the chest.

Answer 69

negative

Question 70

Negative thoracic pressure __ venous return.

Answer 70

increases

Question 71

When the chest cavity expands, it creates __ pressure in the abdomen.

Answer 71

positive

Question 72

Positive abdominal pressure __ venous return.

Answer 72

decreases

Question 73

During expiration, the diaphragm moves...

Answer 73

upward.

Question 74

When the chest cavity contracts, it creates __ pressure in the chest.

Answer 74

increases

Question 75

Increased thoracic pressure __ venous return.

Answer 75

reduces

Question 76

When the chest cavity contracts, it creates __ pressure in the abdomen.

Answer 76

negative

Question 77

Decreased abdominal pressure __ venous return.

Answer 77

increases