Unit 5; Respiratory System Flashcards

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1
Q

What are the 4 functions of the respiratory system

A
  • exchange of gases between atmosphere and blood
  • homeostatic regulation of body pH
  • protection from inhaled pathogens and irritating substances
  • vocalization
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2
Q

What is the first exchange in the respiratory system

A

gas exchange between atmosphere and lungs

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3
Q

What is the second exchange in the respiratory system

A

gas exchange between lungs and blood

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4
Q

What occurs between exchange 2 and 3

A

transport of gases by blood

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5
Q

What is the third exchange in the respiratory system

A

exchange of gases between blood and tissues

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6
Q

What is another term for the transport of gases between atmosphere and lungs

A

ventilation

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7
Q

What is it called when air moves into lungs

A

inspiration or inhalation

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8
Q

What is it called when air moves out of the lungs

A

expiration or exhalation

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9
Q

What is the conducting system of the respiratory system

A

airways

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10
Q

What is the exchange surface of the respiratory system

A

alveoli

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11
Q

What is the pumping system of the respiratory system

A

bones and muscle of thorax

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12
Q

What are the components of the upper respiratory system

A

mouth, nasal cavity, pharynx, larynx
(above trachea)

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13
Q

What are the components of the lower respiratory system

A

trachea, bronchi, bronchioles, lungs
(below trachea and at lungs)

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14
Q

What are alveoli

A

tiny sacs found at the ends of terminal bronchioles wrapped in capillary network - gas exchange occurs between alveoli and capillaries

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15
Q

Why does gas exchange occur specifically at the alveoli

A

small surface area and connected to huge capillary network - allows for efficient diffusion

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16
Q

What are the two types of alveolar cells

A

type 1 and type 2

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17
Q

What are type 1 alveolar cells

A

large but thin
- allow for rapid gas diffusion (thin layer = faster diffusion)

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18
Q

What are type 2 alveolar cells

A

small but thick
- synthesize and secrete surfactant

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19
Q

Where does low oxygen blood exit the heart

A

right ventricle

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20
Q

Where does low oxygen blood travel once it has left the right ventricle

A

pulmonary arteries via the pulmonary trunk

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21
Q

Why is the rate of blood flow high in pulmonary circulation

A

all blood leaving the heart goes to the same place: the lungs

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22
Q

Why is the rate of blood flow lower in systemic circulation

A

the blood leaving the heart flows all around the body, not all to the same place (unlike exchange 2)

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23
Q

Why is blood pressure low in pulmonary circulation

A

right ventricle doesn’t have to contract as hard since its only sending blood to one place

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24
Q

Why is blood pressure higher in systemic circulation

A

left ventricle has to contract harder since it is pushing blood around the body, and not just to one location

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25
Q

Which ventricle pumps more forcefully in the heart

A

the left ventricle (systemic circulation)

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26
Q

What is another term for the chest

A

the thorax

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27
Q

What makes the thorax (chest) a closed compartment

A
  • closed off at top by neck muscles and connective tissues
  • closed off at bottom by the diaphragm
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28
Q

What is the wall of the thorax formed by

A

ribs and intercostal muscles
(costal=ribs, therefore intercostal muscles are literally just muscles at the ribs)

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29
Q

What are the neck muscles involved in the closed compartment of the thorax

A

sternocleidomastoids and the scalenes

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30
Q

What happens when the intercostal muscles contract

A

inspiration

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31
Q

What happens when the intercostal muscles relax

A

passive expiration

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32
Q

What muscles are required for active expiration

A

internal intercostals and the diaphragm

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33
Q

What shape is the diaphragm when relaxed

A

dome

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34
Q

What shape is the diaphragm when contracted

A

flat

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35
Q

When does the volume of the thorax increase

A

when the diaphragm contracts and flattens (inhalation)

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36
Q

When does the volume of the thorax decrease

A

when the diaphragm relaxes and expands (exhalation)

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37
Q

What surrounds the lungs

A

pleural sac

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38
Q

What is found within the pleural sac, and what is its purpose

A

pleural fluid; acts as a lubricant

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39
Q

What is the equation for total gas pressure

A

total pressure = sum of partial pressures

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40
Q

Gas moves from areas of _____ pressure to ______ pressure

A

high to low

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41
Q

What two factors determines if a gas will dissolve in a liquid

A
  • partial pressure of the gas
  • solubility of the gas in liquid
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42
Q

What is the law applied to pressure-volume relationships

A

Boyle’s law

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43
Q

What is the driving force of airflow

A

changes in alveolar pressure

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44
Q

Can the lungs change volume on their own?

A

no!

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45
Q

What does lung volume depend on

A
  • transpulmonary pressure
  • degree of elasticity of the lungs
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46
Q

Pressure inside of the lungs is known as ___________ pressure

A

alveolar

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47
Q

Pressure outside the lungs is known as pressure in the ___________ _________

A

intrapleural fluid

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48
Q

Difference between the alveolar pressure and the pressure of the intrapleural fluid is known as…

A

transpulmonary pressure

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49
Q

What is bulk airflow

A

flow of air between atmosphere and lungs

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50
Q

In what 3 ways do the airways condition the air before it reaches the lungs

A
  1. warm to 37 degrees
  2. add water vapour
  3. filter out foreign material
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51
Q

What are airways lined with

A

ciliated epithelia

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52
Q

What do ciliated epithelia secrete

A

watery saline solution

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53
Q

How do the ciliated epithelia secrete watery saline solution

A

cells move Cl from ECF into the lumen of the cell (via apical ion channel)
Na moves between cells from ECF to the lumen, and the concentration gradient of NaCl draws water towards the lumen creating a watery saline solution

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54
Q

Cilia are covered with _________

A

mucus

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55
Q

What cells secrete mucus

A

goblet cells

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56
Q

What is the mucus escalator

A

when mucus moves up the pharynx and transfers to the digestive tract where bacteria is destroyed

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57
Q

What disease results from a mutation in the Cl channel

A

cystic fibrosis

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58
Q

What is the result of the defective Cl channel in cystic fibrosis

A

insufficient secretion of the watery saline = thick and sticky mucus

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59
Q

What is the subsequent concern with cystic fibrosis

A

the thick and sticky mucus restrains the cilia, which doesn’t allow for proper movement or removal of bacteria = repeated infections (leads to overactive immune cells)

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60
Q

What does the somatic neuron trigger

A

contraction of diaphragm and inspiratory muscles - leads to inspiration

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61
Q

During inspiration, thoracic volume ___________ and alveolar pressure ___________

A

increases, decreases

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62
Q

When impulses from somatic motor neuron stop, what happens

A

diaphragm and thoracic muscles relax = expiration

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63
Q

During expiration, thoracic volume ____________ and alveolar pressure ______________

A

decreases, increases

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64
Q

What is elastic recoil

A

when exhalation occurs, thoracic volume decreases which causes recoil of the lungs and lung volume subsequently decreases

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65
Q

Passive expiration depends entirely on ____________ _________

A

elastic recoil

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66
Q

Active expiration depends on contraction of __________ ________________ and _________ muscles

A

internal intercostals and abdominal muscles

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67
Q

What is a pneumothorax

A

a collapsed lung

68
Q

What causes a pneumothorax

A

air gets into the pleural cavity and increases the pressure, causing the lung to collapse (the pressure difference is abolished)

69
Q

The work required to breathe depends on what 2 factors

A

compliance (stretchability) of the lungs and resistance to airflow in airways

70
Q

What is lung compliance

A

the ability for the lung to stretch

71
Q

If lung compliance is low, is it more or less difficult to expand the lungs

A

more difficult

72
Q

People with LOW lung compliance breathe _________ and __________

A

rapidly and shallowly

73
Q

If lung compliance is high, is it more or less difficult to expand the lungs

A

less difficult

74
Q

People with HIGH lung compliance breathe ________

A

easier

75
Q

What is lung elastance

A

degree and speed at which the lung can return to resting volume after being stretched

76
Q

When lung elastance is low, does the lung return to original volume

A

no, it cannot return to volume passively if lung elastance is low

77
Q

In the case of low lung compliance, is exhalation active or passive

A

active: cannot passively return to original volume

78
Q

What factor most prominently impacts airway resistance

A

diameter

79
Q

Increases in CO2 in the airways causes ___________________

A

bronchodilation (airways open)

80
Q

Histamine (in response to allergies) in the airways causes ____________________

A

bronchoconstriction (airways tighten)

81
Q

Why do people struggle to breathe during anaphylactic shock

A

bronchoconstriction is so severe that the airway is blocked/restricted

82
Q

For neural control of bronchioles, what is the main effector

A

parasympathetic neurons that cause bronchoconstriction
- this is a reflex designed to protect lower respiratory tract from inhaled pathogens

83
Q

Is there any sympathetic innervation in neural control of bronchioles

A

no, not anything significant at least

84
Q

What is the main effector of hormonal control of bronchioles

A

circulating epinephrine

85
Q

How does circulating epinephrine impact bronchioles

A

circulating epinephrine binds to B2 receptors on the smooth muscle of the bronchioles which relaxes muscles to dilate the bronchioles
- this is used as a treatment for asthma

86
Q

What is the point of pulmonary function assessment

A

to determine the amount of air a person moves during quiet breathing and maximal breathing effort

87
Q

What tool is used in pulmonary function assessment

A

spirometer

88
Q

What are the 4 lung volumes that can be measured during breathing

A

tidal volume
inspiratory reserve volume
expiratory reserve volume
residual volume

89
Q

What is tidal volume

A

amount of air moved in and out of the lungs in a single normal inspiration/expiration

90
Q

What in inspiratory reserve volume

A

max amount of air that can be inspired above tidal volume

91
Q

What is expiratory reserve volume

A

max amount of air that can be expired below tidal volume

92
Q

What is residual volume

A

amount of air left in the lungs after maximal expiration

93
Q

The sum of two or more lung volumes is called a…

A

capacity

94
Q

What is vital capacity

A

the max amount of air that can be voluntarily moved into or out of the respiratory system
- VC=IRV+ERV+tidal volume

95
Q

What is total lung capacity

A

TLC=vital capacity+residual volume

96
Q

What is minute volume and how is it calculated

A

measures the effectiveness of breathing
MV=tidal volume+respiratory rate

97
Q

Is there gas exchange within the dead space of the airways

A

no

98
Q

What is alveolar volume and how is it calculated

A

since air in trachea, bronchi, and bronchioles is not included in gas exchange, alveolar volume is the amount of air partaking in exchange
alveolar volume=tidal volume+dead space

99
Q

What is alveolar ventilation and how is it calculated

A

the amount of air that reaches the alveoli each minute
alveolar ventilation=ventilation rate x alveolar volume

100
Q

Alveolar ventilation is matched to alveolar _______ ______

A

blood flow

101
Q

Why does the body try to match ventilation to alveolar blood flow

A

to gain optimum gas exchange

102
Q

Increases in tissue PO2 result in _________________ in the arteriole

A

vasodilation

103
Q

If the ventilation of alveoli in one area of the lung decreases, what happens to the tissue O2 in that area

A

tissue O2 also decreases

104
Q

Decreases in tissue PO2 result in ___________________ of the arteriole

A

vasoconstriction

105
Q

Alterations in blood flow in the lungs depends primarily on what

A

local control exerted by O2 levels in the interstitial fluid around the arteriole surrounding the alveoli

106
Q

If max is breathing 10 times per minute, with a tidal volume of 450mL and a dead space of 150mL, what is his alveolar ventilation?

A

alveolar volume = 300mL (450 - 150 = 300)

ventilation rate x alveolar volume = alveolar ventilation
10 x 300 = 3000 mL/min

107
Q

If Katie is breathing 15 times per minute, with a tidal volume of 375mL and a dead space of 150mL, what is her alveolar ventilation?

A

alveolar volume = 225mL (375 - 150 = 300)

15 x 225 = 3375 mL/min

108
Q

What is the process by which gas exchange occurs

A

diffusion

109
Q

What are the 4 characteristics of the rate of diffusion across the lungs

A
  1. proportional to the partial pressure gradient
  2. proportional to available surface area
  3. inversely proportional to the thickness of the membranes
  4. greatest over short distances
110
Q

What is partial pressure gradient influenced by

A

Composition of inspired air (affected by altitude)
Alveolar ventilation (changes in airway resistance and/or lung compliance)

111
Q

What is emphysema

A

destruction of alveoli
- physical loss of alveolar surface area

112
Q

In emphysema, what happens to the PO2 in the capillary

A

low

113
Q

What is fibrotic lung disease

A

scarring that thickens the alveolar membrane

114
Q

In fibrotic lung disease, what happens to the PO2 in the capillary

A

low

115
Q

What is pulmonary oedema

A

increase in interstitial fluid in lungs

116
Q

What happens as a result of increased interstitial fluid in lungs in pulmonary oedema

A

leads to an increase in diffusion distance (slow)

117
Q

In pulmonary oedema, what happens to PO2 in the capillary

A

low (takes longer to diffuse)

118
Q

What is asthma

A

increase airway resistance, decreased ventilation

119
Q

What occurs as a result of asthma that causes airway resistance

A

bronchiole constriction

120
Q

In asthma, what happens to the PO2 in the capillary AND the alveoli

A

both low

121
Q

Where are gases transported throughout the body

A

plasma or RBCs

122
Q

Since oxygen has low solubility in plasma, most of the oxygen is transported by ________

A

RBCs

123
Q

What does oxygen bind to in RBCs

A

hemoglobin

124
Q

Blood loss results in ______ O2 carrying capacity

A

low

125
Q

Each hemoglobin molecule can bind up to ___ oxygen molecules

A

4

126
Q

What part of hemoglobin does oxygen bind to

A

the iron in the haeme group

127
Q

Hemoglobin bound to oxygen is called

A

oxyhemoglobin (HbO2)

128
Q

Unbound hemoglobin is called

A

deoxyhemoglobin (Hb)

129
Q

How to recognize the % saturation of hemoglobin

A

% of binding sites that are bound to hemoglobin

130
Q

What is a competitive inhibitor of O2 binding

A

carbon monoxide (CO)

131
Q

How does O2 transport in RBCs (explain in a step by step simplified)

A
  • O2 from capillary is dissolved into plasma (small portion will remain but most will go to RBCs)
  • O2 then moves into RBCs and binds to hemoglobin (oxyhemoglobin)
  • oxyhemoglobin is transported to cells
  • O2 unbinds from hemoglobin (deoxyhemoglobin) and enters the cell for cellular respiration
132
Q

What are the three mechanisms by which carbon monoxide is transported

A
  1. dissolved in plasma
  2. interact with proteins
  3. converted to bicarbonate
133
Q

Which is more soluble: CO2 or O2?

A

CO2

134
Q

CO2 is ________ soluble than O2, but cells produce _______ CO2 to be carried

A

more soluble, produces more to be carried

135
Q

What compound is formed when CO2 interacts with proteins during transport

A

carbaminohemoglobin (HbCO2)

136
Q

Which type of hemoglobin interacts with CO2 better: oxyhemoglobin or deoxyhemoglobin

A

deoxyhemoglobin

137
Q

What happens to the majority of CO2 in transport

A

converted to bicarbonate via reaction catalyzed by carbonic anhydrase

138
Q

What enzyme catalyzes CO2 in transport in the blood

A

carbonic anhydrase

139
Q

What transports bicarbonate ions out of the blood cell

A

transporter protein that exchanges HCO3 for Cl (chloride shift)

140
Q

What is the chloride shift

A

when a transporter protein moves bicarbonate out via exchange of HCO3 and Cl

141
Q

When venous blood (blood in veins) reaches the lungs, the PCO2 of alveoli is ________ than that of blood

A

lower

142
Q

CO2 dissolved in plasma diffuses into __________ and then CO2 in RBCs diffuse into _______

A

from plasma to alveoli
from RBCs to plasma

143
Q

When the CO2 diffuses from RBCs to plasma to alveoli, what happens to the reaction

A

the equilibrium of the CO2-bicarbonate reaction is shifted

144
Q

What happens during the reverse chloride shift

A
  • bicarbonate ions move from plasma into RBCs
  • bicarbonate and H+ form carbonic acid
  • carbonic acid forms CO2, which then gets catalyzed by carbonic anhydrase
  • CO2 diffuses out of the RBC into the plasma, then alveoli
145
Q

How does CO2 transport in RBCs (explain in a step by step simplified)

A
  • cellular respiration produces CO2, which moves into plasma, then into RBCs
  • CO2 then forms with hemoglobin to form carbaminohemoglobin
  • some CO2 is catalyzed with carbonic anhydrase to form carbonic acid
  • carbonic acid dissociates into bicarbonate and H+ ions
  • bicarbonate shuttles out to plasma via chloride shift, H+ binds to hemoglobin
  • HbH and carbaminohemoglobin are then transported to the lungs, where the opposite cascade then occurs
  • HbH dissociates into hemoglobin and H+
  • Bicarbonate shuttles into the cell via chloride shift, and binds to H+ to form carbonic acid
  • carbonic acid is catalyzed via carbonic anhydrase to form water and CO2 (CO2 diffuses into plasma)
  • carbaminohemoglobin dissociates into hemoglobin and CO2 (CO2 diffuses into plasma)
  • dissolved CO2 then moves into the capillaries
146
Q

Diaphragm and intercostal muscles are _____________ muscles

A

skeletal muscles

147
Q

What are the diaphragm and intercostals innervated by

A

somatic motor neurons

148
Q

Where in the brain is contraction of the respiratory skeletal muscle initiated

A

medulla oblongata

149
Q

What is the network of neurons called in the medulla oblongata

A

the central pattern generator

150
Q

The central pattern generator (network of neurons) have what kind of activity

A

intrinsic rhythmic activity (fire at a rhythmic rate)

151
Q

What are the two nuclei in the medulla oblongata associated with respiration

A
  1. dorsal respiratory group (DRG): inspiratory neurons (I neurons)
  2. ventral respiratory group (VRG): active expiratory neurons (E neurons)
152
Q

What do the “I neurons” control

A

external intercostal muscles and diaphragm (inspiration)

153
Q

What do the “E neurons” control

A

internal intercostal muscles and abdominal muscles (active expiration)

154
Q

What is the function of chemoreceptors

A

modify or adjust the rhythmicity of the central pattern generator neurons

155
Q

What are the 2 types of chemoreceptors

A
  1. peripheral chemoreceptors
  2. central chemoreceptors
156
Q

Where are peripheral chemoreceptors located

A

in carotid bodies (glomus cells)

157
Q

Peripheral receptors sense changes in…

A

PO2 and pH of plasma
increase in PCO2

158
Q

Decreased PO2, decreased pH, and increased PCO2 in would result in…

A

increased ventilation

159
Q

Are small changes in PO2 enough for signalling to occur

A

no, PO2 must change radically before a signal is sent
- pH usually has more of an impact for this reason

160
Q

Where are central chemoreceptors located

A

in the medulla oblongata

161
Q

What is the most important chemical controller of ventilation

A

medulla oblongata

162
Q

Increased PCO2 in arterial blood (blood carried by arteries) causes what

A

increased ventilation

163
Q

When CO2 crosses the brain barrier into the cerebral spinal fluid (CSF), what happens

A

activates the central chemoreceptors via changes in pH caused by production of carbonic acid

164
Q

What are the two types of mechanoreceptors

A
  1. irritant receptors
  2. stretch receptors
165
Q

Where are irritant receptors located

A

airway mucosa

166
Q

What is the function of the irritant receptors

A

stimulation of irritant receptors triggers parasympathetic neurons that innervate bronchiolar smooth muscle
- leads to bronchoconstriction

167
Q

Where are stretch receptors located

A

in smooth muscle of airways