Lesson 10 Flashcards

1
Q

fluid filter out of the ___ end of the capillary and osmotically reenters ____ end

A
  • arterial
  • venous
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2
Q

what does fluid do as it filters in and out of the cell?

A
  • delivers materials to the cell
  • remove metabolic waste
  • maintain balance between osmosis and hydrostatic pressure
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3
Q

what are the two types of hydrostatic pressure

A
  • capillary hydrostatic pressure
  • interstitial hydrostatic pressure
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4
Q

capillary hydrostatic pressure

A

drives fluid out of capillary

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5
Q

interstitial hydrostatic pressure

A

drives fluid into capillary

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6
Q

hydrostatic pressure is usually high on ____ and low on ____ end

A
  • arterial
  • venous
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7
Q

hydrostatic pressure equation

A

HP = CHP - IHP

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8
Q

colloid osmotic pressure

A

draws fluid into capillary

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9
Q

what does osmotic pressure result from

A

plasma proteins being more abundant in blood than in fluid

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10
Q

oncotic pressure

A

net colloid osmotic pressure

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10
Q

colloid osmotic pressure equation

A

COP = bloodCOP - tissueCOP

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11
Q

net filtration pressure is the difference between

A

net hydrostatic pressure and net osmotic pressure

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12
Q

net filtration pressure equation

A

NFP = (CHP - IHP) - (BCOP - ICOP)

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13
Q

usually in normal condition the IHP and ICOP are

A

equal

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14
Q

capillary exchange at the arterial end characteristicers

A
  • NFP>0
  • net hydrostatic pressure > net osmotic pressure
  • fluid moves out of capillary and into the interstitial fluid
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15
Q

capillary exchange at venous end of capillary characteristics

A
  • NFP<0
  • net osmotic pressure > net hydrostatic pressure
  • fluid moves into capillary and out of interstitial fluid
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16
Q

what is the resulting out net filtration pressure at the arterial end

A

13mmHg out

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17
Q

what is the resulting inward net filtration pressure at the venous end

A

7mmHg inward

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18
Q

why is the net hydrostatic pressure lower at the venous end than at the arterial end

A

blood pressure is lower so oncotic pressure overrides hydrostatic pressure

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19
Q

what is the overall result of the NFP being lower at the venous end than at the arterial end

A

capillary gives off fluid at arterial end and reabsorbs it at the venous end

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20
Q

capillaries reabsorb about ___ of the fluid they filter

A

85%

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21
Q

what is done with the remaining fluid that does not get reabsorbed by the capillaries

A

reabsorbed by lymphoid system and ultimately returned to the blood

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22
Q

____ liter of fluid filtered. ___ liters of fluid reabsorbed.

A
  • 24
  • 20.4
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23
Q

___ liters of fluid drained away by the lymphoid capillaries.

A

3.6

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24
Q

glomeruli of kidneys devoted to

A

filtration

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25
Q

alveolar capillaries in lungs devoted to

A

absorption so fluid doesn’t fill air spaces

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26
Q

characteristics of resting tissue

A
  • most precapillary sphincters constricted
  • capillaries are collapsed
  • BP low
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27
Q

when does reabsorption dominate?

A

resting tissue

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28
Q

characteristics of active tissue

A

capillary pressure rises

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29
Q

when does filtration dominate?

A

active tissue

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30
Q

what happens to fluid filtration/reabsorption in traumatized tissue?

A

release substances that increase permeability and filtration

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31
Q

edema

A

accumulation of excess fluid in a tissue

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32
Q

what is happening in the body during edema?

A

fluid filters into tissue faster than it is absorbed back into the capillary

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33
Q

three primary causes of edema

A
  1. increased capillary filtration
  2. reduced capillary reabsorption
  3. obstructed lymphatic drainage
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34
Q

increased capillary filtration is caused by

A
  • kidney failure
  • histamine
  • old age
  • poor venous return
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35
Q

reduced capillary reabsorption caused by

A
  • hypoproteinemia
  • liver disease
  • dietary protein deficiency
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36
Q

obstructed lymphatic drainage caused by

A

surgical removal of lymph nodes

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37
Q

pathological causes of edema

A
  • tissue death
  • pulmonary edema
  • cerebral edema
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38
Q

severe edema can cause

A

circulatory shock

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39
Q

what causes tissue death

A

oxygen delivery and waste removal impaired

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40
Q

what causes pulmonary edema

A

fluid in lungs

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41
Q

pulmonary edema poses a threat for

A

suffocation

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42
Q

what are the signs and symptoms of cerebral edema

A
  • headaches
  • nausea
  • seizures
  • coma
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43
Q

what causes circulatory shock resulting from severe edema

A

excess fluid in tissue spaces causes low blood volume and low blood pressure

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44
Q

venous return

A

flow of blood back to the heart

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45
Q

what are the five mechanisms used to achieve venous return

A
  • pressure gradient
  • gravity
  • skeletal muscle pump
  • thoracic pump
  • cardiac suction
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46
Q

____ is the most important force in venous return

A

blood pressure

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47
Q

venules have a pressure of

A

12-18 mmHg

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48
Q

central venous pressure

A

point where the venae cavae enter the heart

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49
Q

what is the central venous pressure

A

5mmHg

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50
Q

overall venous pressure gradient of ____ towards heart

A

7-13mmHg

51
Q

gravity does what as a mechanism of venous return

A

drains blood from head and neck

52
Q

how is fluid moved in the skeletal muscle pump

A

contracting limb muscles squeeze blood out of compressed part of vein

53
Q

what keeps moving blood towards the heart in the skeletal muscle pump

A

valves

54
Q

how is blood moved through the thoracic pump (4)

A
  • inhalation expands thoracic cavity
  • thoracic pressure on the inferior vena cava decreases
  • abdominal pressure on the VC increases
  • blood is forced upward towards heart
55
Q

blood flows faster with ___ in the thoracic pump

A

inhalation

56
Q

central venous pressure fluctuates during respiration due to

A

thoracic pump

57
Q

what is central venous pressure during inhalation

A

2mmHg

58
Q

what is the central venous pressure during exhalation

A

6mmHg

59
Q

what are the steps of cardiac suction affecting venous return

A
  • during ventricle contraction valves pulled slightly downward by chordae tendineae and atrial space expands
  • slight suction draws blood into atria from venae cavae and pulmonary veins
60
Q

what are the reasons exercise increases venous return?

A
  • heart beats faster and harder increasing CO and BP
  • vessels of skeletal muscles, lungs, and heart dilate and increase flow
  • increase respiratory rate, increased action of thoracic pump
  • increased skeletal muscle pump
61
Q

venous pooling

A
  • accumulation of blood in limbs venous pressure
  • not enough to force blood upward
62
Q

venous pooling can occur with

A

inactivity

63
Q

with prolonged standing CO may be low enough to cause ____

A

dizziness and syncope

64
Q

venous pooling can be prevented by

A

periodically tensing leg muscles

65
Q

circulatory shock

A

any state in which cardiac output is insufficient to meet body’s needs

66
Q

what are the two forms of circulatory shock

A
  • cardiogenic shock
  • low venous return shock
67
Q

cardiogenic shock

A
  • inadequate pumping of heart
  • usually result of MI
68
Q

low venous return shock

A

cardiac output low because too little blood returns to heart

69
Q

what are the three forms of low venous return shock

A
  • hypovolemic shock
  • obstructed venous return shock
  • venous pooling shock
70
Q

hypovolemic shock

A

loss of blood volume

71
Q

what is the most common form of low venous return shock

A

hypovolemic shock

72
Q

what are the three main reasons for hypovolemic shock

A
  • trauma
  • burns
  • dehydration
73
Q

obstructed venous return shock

A

tumor or aneurysm compressed a vein impeding blood flow

74
Q

venous pooling shock is caused by

A

long periods of standing, sitting, or widespread vasodilation

75
Q

neurogenic shock results from

A

sudden loss of vasomotor tone and vessels dilate

76
Q

what are the possible causes of neurogenic shock?

A
  • brainstem trauma
  • emotional shock
77
Q

other types of shock share characteristics with ____

A

venous pooling and hypovolemic shock

78
Q

septic shock

A

bacterial toxins trigger vasodilation and increased capillary permeability

79
Q

anaphylactic shock

A

severe immune reaction to antigen, histamine release, generalized vasodilation, increased capillary permeability

80
Q

responses to circulatory shock

A
  • compensated shock
  • decompensated shock
81
Q

compensated shock

A

several homeostatic mechanisms bring about spontaneous recovery

82
Q

what is an example of compensated shock

A

is a person faints and falls to a horizontal position, gravity restores blood flow to the brain

83
Q

decompensated shock

A
  • when compensation fails
  • life-threatening positive feedback loops occur
  • condition gets worse causing damage to cardiac and brain tissue
84
Q

what is an example of decompensated shock

A

myocardial ischemia causes MI and decrease CO which slows blood flow to cause disseminated intravascular coagulation to reduce venous return

85
Q

normal blood flow to the brain

A

700 mL/min

86
Q

does blood flow to the brain fluctuate?

A

yes

87
Q

what happens when there is blood deprivation for a few seconds in the brain

A

loss of consciousness

88
Q

what happens when there is blood deprivation for 4-5 minutes?

A

irreversible brain damage

89
Q

though total flow to the brain is constant what happens to blood?

A

shifted to active brain areas from moment to moment

90
Q

____ regulates its own blood flow

A

brain

91
Q

how does the brain regulate its own blood flow?

A

cerebral arteries dilate or constrict as systemic BP drops or rises respectively

92
Q

what is the main chemical stim of blood?

A

pH

93
Q

poor perfusion leads to ____ accumulation in the brain

A

CO2

94
Q

what happens when there is CO2 accumulation in the brain

A
  • pH decreases
  • triggers vasodilation
95
Q

low CO2 in brain leads to what?

A
  • pH increases
  • stims vasoconstriction
96
Q

when does low CO2 concentration in the brain occur

A

hyperventilation

97
Q

what can low CO2 concentration in the brain cause

A
  • ischemia
  • dizziness
  • syncope
98
Q

hypercapnia

A

CO2 accumulation in the brain

99
Q

hypocapnia

A

low levels of CO2 in the brain

100
Q

Transient ischemic attacks

A

brief episodes of cerebral ischemia

101
Q

what are transient ischemia attacks caused by

A

spasms of diseased cerebral arteries

102
Q

what can transient ischemia attacks cause

A
  • dizziness
  • vision loss
  • weakness
  • paralysis
  • headache
  • aphasia
103
Q

how long do transient ischemia attacks last

A

a few moments to a few hours

104
Q

what can transient ischemia attacks be early warning signs for

A

impending stroke

105
Q

cerebral vascular accident aka

A

stroke

106
Q

what is a stroke?

A

sudden death of brain tissue caused by ischemia

107
Q

what can cause a stroke

A
  • atherosclerosis
  • thrombosis
  • ruptured aneurysm
108
Q

what are the possible side effects of a stroke?

A
  • blindness
  • paralysis
  • loss of sensation
  • loss of speech
109
Q

what is the most common effect of a stroke

A

loss of speech

110
Q

what does recovery from a stroke depend on?

A

surrounding neurons and collateral circulation

111
Q

variable blood flow depends on

A

state of exertion

112
Q

what is variable blood flow at rest?

A
  • arterioles constrict
  • most capillary beds shut down
  • total flow about 1L/min
113
Q

what is variable blood flow during exercise?

A
  • arterioles dilate in response to muscle metabolites
  • blood flow can increase 20-fold as blood is diverted from the digestive and urinary organs
114
Q

muscle metabolites include

A
  • lactate
  • CO2
  • H+
115
Q

how does muscular contraction impede blood flow?

A

by compressing blood

116
Q

_____ contractions cause fatigue faster

A

isometric contraction

117
Q

lungs have ___ pulmonary blood pressure

A

low

118
Q

pressure in pulmonary arteries

A

25/10 mmHg

119
Q

____ overrides blood pressure

A

oncotic pressure

120
Q

pulmonary capillaries ___ fluid

A

absorb

121
Q

why do pulmonary capillaries absorb fluid

A

prevent fluid accumulation in alveoli

122
Q

what is the pulmonary response to hypoxia?

A

pulmonary arteries constrict in diseased area or areas of the lung that are receiving less oxygen from outside redirecting blood to better-ventilated region of lung

123
Q

what is the systemic arteries response to hypoxia

A

dilate to increase tissue perfusion

124
Q
A