Ch. 18 Physics: Hemodynamics Flashcards

1
Q

THE STUDY OF BLOOD MOVING THROUGH THE CIRCULATORY SYSTEM

A

Hemodynamics

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2
Q

Volume of blood at a particular time

A

Flow (volume flow rate)

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3
Q

Speed of fluid from one location to another

A

Velocity

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4
Q

How is flow rate measured?

A

volume/time

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5
Q

How is velocity measured?

A

distance/ time

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6
Q

Looking at the monitor what the is peak velocity abreviation?

A

PS

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7
Q

Looking at the monitor what is the velocity flow rate located?

A

Bottom where it says VolFlow

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8
Q

What are the 3 type of flow?

A

Pulsatile

Phasic

Steady

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9
Q

What is pulsatile flow rate?

A

Variable velocity

Changes with cardiac contractions

Usually, arterial

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10
Q

What is phasic flow rate?

A

ariable velocity

Changes with respiration

Usually, venous

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11
Q

What is steady flow rate?

A

Constant velocity

Often in venous flow when holding respiration

(or upstream obstruction)

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12
Q

The way blood flows through vessels can be described as _________ or __________

A

laminar or turbulent.

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13
Q

predicts whether flow is laminar or turbulent.

A

Reynolds number

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14
Q

“Silent flow”, Flow streamlines are aligned and parallel, and Layers of blood in a vessel travel at individual speeds all describe what?

A

Laminar flow

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15
Q

What are the 2 forms of laminar flow?

A

PLUG FLOW

PARABOLIC FLOW

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16
Q

What is plug flow?

A

all layers travel at the same speed

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17
Q

What is parabolic flow?

A

highest velocities in the center, decreases closer to the vessel wall

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18
Q

Chaotic flow pattern traveling in many different directions and speeds, Eddy current (vortex) – hurricane-like, swirling, rotational patterns, Often associated with pathology, is all describing what kind of flow?

A

Turbulent

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19
Q

Which flow converts flow energy into sound and vibrational energy?

A

Turbulent

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20
Q

When turbulent flow is present how is the sound described? how is the vibration described?

A

bruit

thrill

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21
Q

What is it called Blood moves from higher energy to lower energy and Energy is imparted onto the blood stream by the left ventricle?

A

Energy gradient

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22
Q

What are the 3 different forms of blood energy?

A

Kinetic

pressure

gravitational

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23
Q

What is it called when all 3 forms of blood energy are combined?

A

Total energy

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24
Q

True or false:
Energy gradient Cannot be created or destroyed, only transferred.

A

true

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25
Q

MOVING OBJECTS and DETERMINED BY MASS and SPEED describes what kind of blood enery?

A

Kinetic

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26
Q

STORED (POTENTIAL) ENERGY, ABILITY TO PERFORM WORK, MAJOR FORM OF ENERGY FOR BLOOD CIRCULATION, all describes what kind of blood energy?

A

Pressure

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27
Q

STORED (POTENTIAL) ENERGY, ASSOCIATED WITH ANY ELEVATED OBJECT, IDENTICAL OBJECTS AT THE SAME HEIGHT HAVE THE SAME GRAVITATIONAL ENERGY, all describes what kind of blood energy?

A

Gravitational

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28
Q

What is another term when we say that energy is lost?

A

transferred

29
Q

What are the 3 ways energy is lost?

A

Viscous

Frictional

Intertial

30
Q

THICKNESS OF FLUID (HONEY VS WATER) and is Measured in units of Poise

A

Viscosity

31
Q

Amount of energy loss in blood is measured by

A

hematocrit

32
Q

What is hematocrit?

A

% of blood made up of RBC’s

33
Q

True or false:

MORE ENERGY IS LOST WITH HIGH VISCOSITY LIQUIDS

A

True

34
Q

FLOW ENERGY IS CONVERTED TO HEAT AS OBJECTS RUB AGAINST EACH OTHER is what kind of loss of energy?

A

Frictional

35
Q

ENERGY IS LOST WHEN SPEED CHANGES and OCCURS DURING 3 EVENTS; PULSATILE FLOW, PHASIC FLOW, STENOSIS, describes what kind of loss of energy?

A

intertial

36
Q

NARROWING IN THE LUMEN OF A VESSEL

A

stenosis

37
Q

How does stenosis affect blood flow?

A

CHANGES IN DIRECTION

INCREASED VELOCITY WITHIN STENOSIS (HIGHEST WHERE NARROWEST)

POST-STENOTIC TURBULENCE

38
Q

What kind of currents fill the vessel when the lumen expands after stenosis?

A

Eddy

39
Q

High pressure pre-stenosis, low pressure post-stenosis, describes what?

A

pressure gradient across stenosis

40
Q

Where is velocity highest in stenosis?

A

At the most narrow segment

41
Q

Where is turbulent blood flow seen in stenosis?

A

Distal to the narrowing

42
Q

What happens post stenosis?

A

loss of pulsatility

43
Q

DESCRIBES THE RELATIONSHIP BETWEEN VELOCITY AND PRESSURE IN A MOVING FLUID and IS DERIVED FROM THE LAW OF CONSERVATION OF ENERGY

A

BERNOULLI’S PRINCIPLE

44
Q

AS PRESSURE ___________, VELOCITY DECREASES

A

INCREASES
they are inversely related

45
Q

what is the formula for when THE PRESSURE GRADIENT INCREASES IF FLOW OR RESISTANCE INCREASES?

A

PRESSURE GRADIENT = FLOW (Q) X RESISTANCE (R)

46
Q

What is the formula for when THE FLOW INCREASES WHEN THE PRESSURE GRADIENT INCREASES OR RESISTANCE DECREASES?

A

FLOW (Q) = PRESSURE GRADIENT/ RESISTANCE (R)

47
Q

RESISTANCE INCREASES WITH

A

THE LENGTH OF THE TUBE

VISCOSITY

48
Q

RESISTANCE DECREASES WITH:

A

DECREASED RADIUS

49
Q

DESCRIBES THE WAY ELECTRICITY FLOWS THROUGH A WIRE.
SIMILAR TO HOW BLOOD FLOWS THROUGH A VESSEL

A

Ohm’s law

50
Q

OHM’S LAW STATES THAT:

A

VOLTAGE = CURRENT X RESISTANCE

(PRESSURE = FLOW X RESISTANCE)

51
Q

VEINS HAVE THIN, COLLAPSIBLE WALLS THAT CHANGE SHAPE WITH __________.

A

PRESSURE

52
Q

In venous hemodynamics, IN A LOW-PRESSURE SETTING, THE WALLS WILL ____________.

A

collapase

53
Q

In venous hemodynamics, IN A HIGH-PRESSURE SETTING, THE WALLS WILL _________.

A

expand

54
Q

DURING EXERCISE, THE VEINS EXPAND creating what?

A

LOWER RESISTANCE AND INCREASE IN VESSEL DIAMETER

55
Q

INCREASE IN VESSEL DIAMETER means what?

A

INCREASE IN FLOW TOWARD THE HEART

56
Q

what is the formula for hydrostatic pressure?

A

Hydrostatic pressure (P)= height (h) x gravity (g) x density of blood (p)

57
Q

PRESSURE RELATED TO THE WEIGHT OF BLOOD PRESSING ON A VESSEL, MEASURED AT A HEIGHT ABOVE OR BELOW THE HEART

A

Hydrostatic pressure

58
Q

BLOOD PRESSURE IS ACCURATELY ASSESSED AT THE LEVEL OF THE ___________.

A

heart

59
Q

what is the measurements of hydrostatic pressure?

A

units of mmHg

60
Q

What is the level of hydrostatic pressure at heart level?

A

0

61
Q

True or false:
If the body is in supine position, hydrostatic pressure will be 0 through out the body regardless of where it is taken.

A

True

62
Q

If the patient is standing, hydrostatic pressure below the heart is what? positive or negative?

A

Positive, it will be higher than actual circulatory pressure

63
Q

If the patient is standing, hydrostatic pressure above the heart is what? positive or negative?

A

Negative, it will be lower than actual circulatory pressure

64
Q

Venous flow is affected by

A

respiration

65
Q

What are the two reasons venous flow is affected by respiration?

A

Venous system is low pressure

Muscles responsible for respiration (diaphragm) alter pressures in the thorax and the abdomen

66
Q

Two venous flows affected by respiration

A

Venous flow in the legs

Venous flow returning to the heart from the head, arms, and IVC

67
Q

Decreased thoracic pressure

Increased upper extremity venous flow

Increased abdominal pressure

Decreased lower extremity flow

This describes inspiration or expiration in venous hemodynamics?

A

Inspiration

68
Q

Increased thoracic pressure

Decreased upper extremity venous flow

Decreased abdominal pressure

Increased lower extremity flow

This describes inspiration or expiration in venous hemodynamics?

A

Expiration