LESSON 18 - venous return and the pulmonary circulation Flashcards

1
Q

describe venous circulation :

A

a conduit return blood to the right side of the heart from the periphery

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2
Q

describe the type of blood veins circulate :

A

veins return oxygenated blood to the heart but deoxygenated blood in rest of the body

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3
Q

how many reservoirs for blood volume ?

A

5

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4
Q

what are the 5 reservoirs for blood volume ?

A
  • pulmonary
  • veins
  • heart
  • arteries
  • arterioles, capillaries
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5
Q

what % of “reservoir” for blood volume is in the pulmonary ?

A

9%

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6
Q

what % of “reservoir” for blood volume is in the veins ?

A

64%

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7
Q

what % of “reservoir” for blood volume is in the arterioles & capillaries ?

A

7%

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8
Q

what % of “reservoir” for blood volume is in the arteries ?

A

13%

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9
Q

what % of “reservoir” for blood volume is in the heart ?

A

7%

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10
Q

what is venous return (VR) ?

A

volume of blood that returns from the veins to the ratio each minute

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11
Q

FILL IN THE BLANK

“venous return = rate of blood return from the ____ to the _____ “

A

veins to the atrium

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12
Q

describe the venous return and cardiac output closed loop :

A

right ventricle … pulmonary … left ventricle … systemic …

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13
Q

where within the closed loop do we see VR (venous return) ?

A

systemic to right ventricle

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14
Q

where within the closed loop do we see CO (cardiac output) ?

A

right ventricle to pulmonary and left ventricle to systemic

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15
Q

FILL IN THE BLANK

venous return = _________ = _________

A

right ventricle output = left ventricle output

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16
Q

TRUE OR FALSE

all pumps have to be operated at the same speed

A

TRUE

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17
Q

why must all pumps have to be operated at the same speed ?

A

to sustain that high level of cardiac output

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18
Q

during exercise, an increase in venous return = ?

A

increase right ventricle and left ventricle filling

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19
Q

how does venous return increase ?

A

during exercise (think of cardiac output)

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20
Q

what is the formula for venous return (VR) ?

A

VR = ΔP / TVR

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21
Q

what is TVR ?

A

resistance in the large veins and vena cave

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22
Q

what is ΔP ?

A

pressure differential

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23
Q

what is P venous (peripheral venous pressure) ?

A

pressure in the peripheral veins draining tissues

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24
Q

which part of the venous return system is the highest point of pressure ?

A

the beginning of the system

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25
Q

which parts of the circulatory system are a high pressure system and high resistance ?

A
  • left ventricle
    -arteries
  • arterioles
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26
Q

which parts of the circulatory system are a low pressure system and low resistance ?

A
  • venules
  • veins
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27
Q

between arteries and veins which have more smoother muscles ?

A

arteries

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28
Q

within the circulatory system which are the exchange vessels ?

A

capillaries

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29
Q

do we see low or high resistance in the venous circulation ?

A

low resistance

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30
Q

describe the anatomy of veins :

A
  • thinner walls
  • lack of smooth muscle
  • lack of sympathetic tone
  • more compliant
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31
Q

describe the anatomy of arteries :

A
  • thicker walls
  • lots of smooth muscle
  • more elasticity
  • easier to return to original state
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32
Q

between veins and arteries which are more compliant ?

A

veins

33
Q

what does compliant mean ?

A

the ability of a blood vessel to adjust the blood pressure and increase the volume of blood that it can hold

34
Q

between veins and arteries which are more likely to blow open ?

A

venis

35
Q

between veins and arteries which have a higher resistance ?

A

arteries

36
Q

does venous return have any effect on stroke volume ?

A

no

37
Q

why do we see increasing preload ?

A

to facilitate the rise in venous return

38
Q

what is preload ?

A

the volume of blood received by the heart during (EDV)

39
Q

what does an increase in venous return mean for preload ?

A

increase in preload

40
Q

what is after load ?

A

how much blood is left in the left ventricle

41
Q

TRUE OR FALSE

“the preload is the highest amount getting ready for contraction”

A

TRUE

42
Q

what are the effects of posture on venous pressure ?

A

when standing from supine, gravitational forced “pull” venous blood to the lower limbs

43
Q

FILL IN THE BLANK

“due to the high compliance of veins around ____ mL of blood can redistribute to peripheral veins”

A

500mL

44
Q

“ever felt light headed when standing” is an example of what topic ?

A

effect of posture on venous pressure

45
Q

what is adema ?

A

buildup in blood volume

46
Q

does gravity pull blood volume up or down ?

A

down (ex. survivor challenge)

47
Q

if you’re standing up for too long and feel light headed, what do we do to get rid of that gravitational force and to make the blood flow better ?

A

laying down

48
Q

is an increase in venous return necessary to increase cardiac output ?

A

yes, an increase in venous return is necessary to increase cardiac output

49
Q

an increase in what three things leads to an increase in cardiac output

A
  • venous return
  • EDV
  • stroke volume
50
Q

how do venous blood flow in one direction ?

A

valves (prevent back flow, help continuously bring blood, etc)

51
Q

where do veins in the systemic system direct blood ?

A

direct blood to right atrium

52
Q

describe the valves in veins :

A
  • thin
  • membranous flap-like valves
  • spaced at short intervals within veins
53
Q

what is the purpose of having valves ?

A

permit one way blood flow back to heart

54
Q

describe the pressure of blood in the large veins :

A

pressure of blood in the large veins is very low (difficult to return blood to heart)

55
Q

what are vessels within nucleus well tethered to ?

A

surrounding tissues (transmission of forces)

56
Q

when in the upright posture, gravity oppose what type of flow of blood and from where ?

A

gravity opposes the upward flow of blood from the lower body

57
Q

what are required to help increase venous return (veins/valves) ?

A

active mechanisms

58
Q

describe a skeletal muscle pump :

A

the mechanism whereby skeletal muscles aid the return of blood to the heart by compressing embedded veins

59
Q

what happens during exercise if there were no muscle pump ?

A

high flow of blood through muscle would lead to pooling in compliant vasculature

60
Q

what do muscle pumps prevent ?

A

pooling by maintaining a low volume of blood volume within muscle veins and displacing it back to heart

61
Q

what does tethering cause with skeletal muscle pump ?

A

causes negative venous pressure which “sucks” blood through muscle above what could be provided by left ventricle force alone

62
Q

describe veins during muscle contraction :

A
  • muscles shorten
  • muscle pushes veins (massage like)
  • helps blood flow
63
Q

describe veins during muscle relaxation :

A
  • muscles are not being pushed
  • generates forward pressure that shoots blood upwards towards the heart
    muscle lengthening
64
Q

what is the respiratory muscle pump ?

A

consists of abdominal and thoracic structures that are important in the expansion and contraction of the lungs

65
Q

what does decent of diaphragm during inspiration do to intra-abdominal pressure and pressure gradient between the thorax and abdomen (causing translation of blood centrally)

A

increase intra-abdominal pressure and increase in pressure gradient between thorax and abdomen

66
Q

during inspiration how does the diaphragm move ?

A

moves down

67
Q

during expiration how does the diaphragm move ?

A

moves up

68
Q

when does inspiration decrease intrathoratic pressure and increase pressure gradient ?

A

between the RA and system venous circuit (outside thoracic cavity)

69
Q

when the thoracic cavity decreases what does it mean for blood ?

A

increase in blood

70
Q

what happens to thoracic pressure of abdomen and thoracic cavity when you push diaphragm down ?

A

increase thoracic pressure of abdomen and thoracic cavity

71
Q

what is driving pressure ?

A

the difference between plateau pressure and positive end-expiratory pressure

72
Q

TRUE OR FALSE ?

the right and left heart both circulate the same volume of blood at the same frequency

A

TRUE

73
Q

@ rest what is the L/min ?

A

5

74
Q

with low resistance circulation; pressure generated by RV is much less or much more than the left ?

A

much less

75
Q

@ severe exercise what is the L/min ?

A

20+

76
Q

describe the relationship of the Q LV vs Q RV on a graph :

A
  • always the exact same
  • growing exponentially together
77
Q

describe the relationship of systemic arterial vs pulmonary arterial pressure on a graph :

A

significantly more pressure is generated on the L side (systemic) over the R side (pulmonary)

78
Q

describe the relationship of systemic peripheral vs pulmonary vascular resistance on a graph :

A

systemic starts super high and eventually falls way down while pulmonary maintains pretty low down

79
Q

what does greater aerobic fitness mean for resistance ?

A

less resistance in the pulmonary vasculature