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Physiology II - HLSC 128 > Chapter 13- Respiratory System > Flashcards

Chapter 13- Respiratory System Flashcards

1
Q

What is the respiratory system’s main function?

A

-Supply body tissues wit O2
-Dispose of CO2 produced by cellular metabolism

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2
Q

What are the two main processes of the Respiratory system?

A
  1. Internal respiration
  2. External respiration
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3
Q

What is external respiration?

A

Gas exchange between the external environment and the body cells

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4
Q

What is internal respiration?

A

Cellular respiration

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5
Q

What are the 4 steps of external respiration?

A
  1. Ventilation
  2. Exchange of O2 and CO2 in alveoli and pulmonary capillaries
  3. Transport of O2 and CO2 between lungs and tissues via blood
  4. Gas exchange between tissues and systemic capillaries
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6
Q

What is ventilation?

A

Movement or air into and out of the lungs

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7
Q

What is nonrespiratory function of the respiratory system?

A

Helps maintain normal acid-base balance

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8
Q

What is the anatomy of the respiratory system?

A

Airways
Lungs and alveoli
Structures of the thorax involved in air movement

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9
Q

What are the respiratory airways function?

A

Tubes that carry air between the atmosphere and the air sacs

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10
Q

What are all the respiratory airways?

A
  1. Nasal passages
  2. Pharynx
  3. Trachea
  4. Larynx
  5. Right and left bronchi
  6. Bronchioles
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11
Q

What are the lungs divided into and supplied by?

A

Two lungs divided into several lobes
Each supplied by one bronchi

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12
Q

What do the lungs consist of?

A

-HIghly branched airways
-Alveoli
-Pulmonary blood vessels
-Large quantities of elastic connective tissue

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13
Q

What do bronchioles walls contain?

A

Smooth muscle innervated by the autonomic nervous system
-NO CARTILAGE

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14
Q

Where are alveoli located?

A

Clustered at the ends of terminal bronchioles

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15
Q

What re bronchioles sensitive to?

A

Certain hormones and local chemicals

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16
Q

What zone do the Trachea and bronchi belong to?

A

Convection zone

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17
Q

What are the Trachea and bronchi?

A

Rigid, nonmuscular tubes made from cartilage rings (prevent collapse)

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18
Q

What zone do the bronchioles belong to?

A

Diffusion zone

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19
Q

What is the function of alveoli?

A
  1. Gas exchange (Air sacs)
  2. Increase surface area
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20
Q

What are the types of alveoli?

A

Type I
Type II

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21
Q

What are Type I alveoli?

A

Walls have a single layer of flattened epithelial cells

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22
Q

What are Type II alveoli?

A

Secrete pulmonary surfactant

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23
Q

What is the thorax/outer chest wall formed by?

A

12 pairs of ribs
Sternum
Thoracic vertebrae

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24
Q

What is the function of the thorax?

A

Protect lungs and heart
Contains muscles involved in generating pressure that causes air flow

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25
Q

What are the main inspiratory muscles?

A

Diaphragm
External intercostal muscles

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26
Q

What nerve innervates the Diaphragm?

A

Phrenic nerve

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27
Q

What nerve innervates the External intercostal muscles?

A

Intercostal nerve

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28
Q

What are the expiratory muscles?

A

Internal intercostal muscles and abdominal muscles

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29
Q

What is the name of serous membrane sac for the Lungs?

A

Pleural sac

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30
Q

What is the pleural sac?

A

Double walled, closed sac
-separates each lung from the thoracic wall

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31
Q

What is interior to the pleural sac?

A

Pleural cavity

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32
Q

What do the surfaces of the pleura secrete?

A

Intrapleural fluid (Fills pleural cavity)

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33
Q

What is the function of intrapleural fluid?

A

Lubricate pleural surfaces

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34
Q

What are the two layers of the pleural sac?

A

Parietal membrane (Most external layer, by thoracic wall)
Visceral membrane (Surface of the lung)

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35
Q

What is the Pleural sac’s function?

A

Allow lungs and thorax to slide past each other during breathing

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36
Q

What are the 4 different pressures important in ventilation?

A
  1. Atmospheric (barometric) pressure
  2. Intra Alveolar pressure
  3. Intra Pleural pressure
  4. Transpulmonary pressure
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37
Q

Example of an atmospheric pressure important in ventilation?

A

Sea level

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38
Q

What is the pressure of Sea level?

A

760 mmHg

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39
Q

What is the transmural pressure gradient?

A

Pressure gradient across the lungs
Inside pressure - outside pressure

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40
Q

What is the function of the Transmural pressure gradient?

A

Keep lung and chest wall together
-Lungs= Distentible and have elastic recoil
-Thoracic wall= Rigid and recoils outward

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41
Q

The pleural sac always has what pressure?

A

Subatmospheric pressure

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42
Q

What is elastic recoil in the lungs?

A

How readily the lungs rebound after being stretched so lungs can return to preinspiratory volume

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43
Q

What 2 factors do the Lung’s Elastic recoil depend on?

A
  1. Elastic connective tissue in the lungs (Stretchability)
  2. Alveolar surface tension
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44
Q

What creates alveolar surface tension?

A

The thin liquid film that lines each alveolus

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45
Q

What two aspects of alveolar surface tension produce the Lung’s elastic recoil?

A
  1. The liquid resists alveoli expansion making them less compliant
  2. Liquid lining on alveolus shrinks alveoli making them recoil
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46
Q

What would happen if only water lined the alveoli?

A

They would collapse

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47
Q

What makes alveoli more likely to collapse?

A

Smaller size and greater surface tension

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48
Q

What two factors oppose the tendency of alveoli to collapse?

A
  1. Pulmonary surfactant
  2. Alveolar interdependence
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49
Q

What is pulmonary surfactant?

A

Complex mixture of phospholipids and proteins secreted by Type II alveoli

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50
Q

What does Pulmonary surfactant do?

A

Reduces surface tension

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51
Q

How does Pulmonary surfactant reduce surface tension?

A

By dispersing between the water molecules that line the alveoli therefore reducing the cohesive force between water molecules

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52
Q

What increases the secretion of Pulmonary surfactant?

A

Deep breathing

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53
Q

What are the two benefits of Pulmonary surfactant?

A
  1. Reduces the work of the lungs
  2. Reduces recoil pressure of smaller alveoli more than larger alveoli
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54
Q

What is the overall effect of pulmonary surfactant?

A

Equalize pressures of different size alveoli, minimising the tendency of smaller ones to empty into larger ones and avoid collapse
-Stabilize alveoli
-Maintain gas exchange

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55
Q

Why do premature babies have difficulty breathing?

A

They lack surfactant (IRDS or RDSN)
-Alveoli collapse
-Alevoli have to re inflate every time =Energy drain

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56
Q

When is pulmonary surfactant made?

A

Last two months of utero

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57
Q

What are prevention methods of IRDS and RDSN?

A

Give mother steroids to trigger surfactant production
Give baby artificial surfactant while on a ventilator

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58
Q

How does alveolar interdependence contribute to alveolar stability?

A

Because all alveoli are connected to each other when one starts to collapse surrounding alveoli recoil to keep it open

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59
Q

What force do the surrounding alveoli exert on the collapsing alveoli?

A

Expanding force
-triggered when walls of alveoli are stretched and pulled in direction of collapsing alveolus

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60
Q

What is a pneumothorax?

A

Abnormal condition of air entering the pleural space

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61
Q

What happens to pressure gradient during a pneumothorax?

A

It no longer exists across the lung or chest wall
-Pleural and alveolar pressure now equal atmospheric pressure

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62
Q

Why does the lung collapse during a pneumothorax?

A

Because there is no opposing negative pleural pressure to keep it inflated

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63
Q

What is Boyle’s Law?

A

At any constant temp, the pressure exerted by a gas varies inversely with the volume of a gas

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64
Q

What is the formula for Boyle’s Law?

A

P1V1=P2V2
or P=1/V

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65
Q

What produces flow of air into and out of the lungs?

A

Changes in alveolar pressure

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66
Q

What happens when alveolar pressure is less than atmospheric pressure?

A

Air enters the lungs

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67
Q

What happens when alveolar pressure is greater than atmospheric pressure?

A

Air exits from the lungs

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68
Q

What happens when lung volume is altered?

A

Pressure changes in lungs
Air flow is generated

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69
Q

What changes the volume of the thoracic cavity?

A

respiratory muscle activity

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70
Q

What inspiratory muscle is responsible for 75% of thoracic volume change at rest?

A

Diaphragm

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71
Q

What DECREASES the size of the chest cavity?

A

-Relaxation of the diaphragm and chest wall muscles + Elastic recoil of the alveoli

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72
Q

What begins by the relaxation of inspiration muscles?

A

Onset of expiration

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73
Q

Expansion during inspiration decreases which pressure?

A

Intrapleural pressure

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74
Q

What happens to the lungs during expansion?

A

They are drawn into an area of lower pressure and expand

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75
Q

What happens to alveolar pressure to allow air to enter the lungs?

A

It lowers to a pressure level below atmospheric pressure

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76
Q

What happens to alveolar pressure to allow expiration (air exits)?

A

It increases to a level above atmospheric pressure and air is driven out

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77
Q

What happens to idntraalveolar pressure to cease outward flow?

A

Intralveolar pressure equals atmospheric pressure

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78
Q

What allows for forced expiration?

A

Contraction of expiratory muscles

79
Q

What is air flow dependent on?

A
  1. Pressure differences
  2. Airway resistance
80
Q

What is the formula for airflow?

A

F=ΔP/R

81
Q

What is ΔP?

A

Difference between atmospheric and intra-alveolar pressure

82
Q

What is airway resistance determined by?

83
Q

What changes the radius of airways?

A

Autonomic nervous system controls smooth muscle contraction in airway walls

84
Q

What does the Sympathetic nervous system do to airways?

A

Causes Bronchodilation
-releases NE (nerve endings in lungs) and Epinephrine

85
Q

What does the Parasympathetic nervous system do to airways?

A

Causes bronchoconstriction
-releases ACh from nerve endings in the lungs

86
Q

What happens to airways that are narrowed by disease states?

A

Flow is restricted
More work to breathe

87
Q

Formula for flow in disease states?

A

F=↑ΔP/↑R

88
Q

What abnormally increases airway resistance?

A

Chronic pulmonary disease
-Expiration is harder than inspiration

89
Q

What are examples of diseases that increase airway resistance?

A
  1. Asthma
  2. COPD
90
Q

What happens during an Asthma attack that narrows airways?

A
  1. Smooth muscle spasm
  2. Airway walls thicken (Inflammation, histamine-induced edema)
  3. Muscous is secreted
    —> can lead to infections
91
Q

What is COPD?

A

Chronic obstructed pulmonary disease

92
Q

What are COPD cases caused by?

A

Cigarette smoke (80%) or chemicals like coal dust, asbestos

93
Q

What are the 2 types of COPD?

A
  1. Chronic bronchitis
  2. Emphysema
94
Q

What is Chronic bronchitis?

A

A long term inflammatory condition of smaller airways

95
Q

What is NOT the cause of obstruction in COPD?

A

Smooth muscle contraction is not the cause

96
Q

What causes chronic bronchitis?

A

Prolonged exposure to smoke, allergens etc

97
Q

How are airways obstructed by chronic bronchitis?

A

a. Edematous thickening of airway lining
b. Thick mucous secreted

98
Q

Why do those with chronic bronchitis get bacterial infections?

A

Coughing can’t remove the mucous out of the lungs

99
Q

What is Emphysema?

A

Collapse of smaller airways and alveolar wall breakdown

100
Q

What is most commonly responsible for emphysema?

A

Over release of destructive (proteolytic) enzyme Trypsin

101
Q

What is the maximum lung volume of adult male and female?

A

Male= 5.7L
Female= 4.2L

102
Q

What is lung volume at rest?

A

2.2L
-Lungs are still half-full to continue gas-exchange

103
Q

What a spirometer?

A

Device that measures the volume of air breathed in and out

104
Q

Capacities are equal to?

A

The sum of 2 or more lung volumes

105
Q

What is Tidal volume? TV

A

Volume of air entering or leaving lungs during a single breath
500mL

106
Q

What is residual volume? RV

A

Minimum volume of air remaining in the lungs even after a maximal expiration
1200mL

107
Q

What is Vital capacity? VC

A

Maximum volume of air that can be moved out during a single breath following a maximal inspiration (VC = IRV + TV + ERV)
4500mL

108
Q

What is Total lung capacity? TLC

A

Maximum volume of air that can be moved out during a single breath following a maximal inspiration (VC = IRV + TV + ERV)
5700mL

109
Q

What are 2 categories of respiratory dysfunction that give abnormal spirometry results?

A
  1. Obstructive lung disease
  2. Restrictive lung disease
110
Q

What is Forced expiratory volume in 1 second (FEV1) in obstructed lung disease?

A

Less than 80%

111
Q

What does restrictive lung disease cause?

A

Reduced vital capacity
-Normal airway resistance

112
Q

What causes restrictive lung disease?

A

Impaired respiratory movements

113
Q

What is Pulmonary ventilation?

A

Volume of air breathed in and out in one minute
-aka Minute ventilation

114
Q

Formula for Pulmonary ventilation?

A

Pulmonary ventilation (ml/min) = tidal volume (ml/breath) x respiratory rate (breaths/min)

115
Q

What is alveolar ventilation?

A

Volume of air exchanged between the atmosphere and the alveoli per minute

116
Q

Which kind of ventilation (pulmonary or alveolar) is more important?

A

Alveolar ventilation

117
Q

What is the average airway volume in adults?

118
Q

Why is alveolar less than pulmonary ventilation?

A

Because of anatomic dead space
-There is a volume of air in the conducting airways that is useless for exchange

119
Q

Alveolar ventilation formula?

A

Alveolar ventilation= (Tidal volume- dead space) x respiratory rate

120
Q

What amount of energy is required for normal work of breathing? (quiet breathing)

A

3% of total energy expenditure

121
Q

What situations increase the work of breathing?

A

Increased ventilation
Decreased pulmonary compliance
Increased airway resistance
Decreased elastic recoil

122
Q

Example of situations where there is a need for increased ventilation?

A

Exercise
-10-15% of O2 consumption

123
Q

Example of when there is decreased pulmonary compliance?

124
Q

Example of when there is increased airway resistance?

125
Q

Example of when there is decreased elastic recoil?

126
Q

What is gas exchange?

A

Simple diffusion of o2 and CO2 down partial pressure gradients until partial pressures are equilibrated

127
Q

In what capillaries does gas exchange occur?

A

Pulmonary and systemic tissue capillaries

128
Q

How much air moves in and out with each breath?

A

500ml/breath

129
Q

What is a partial pressure?

A

The pressure exerted by an individual gas in a mixture

130
Q

What is the partial pressure of H20 in airways?

131
Q

What does the addition of water vapour in airways do to partial pressures?

A

“dilutes” all gases by 47mmHg

132
Q

What is functional residual capacity?

133
Q

What happens to oxygen and carbon dioxide partial pressure gradients in the LUNGS?

A
  1. O2 diffuses from alveoli to pulmonary capillaries
  2. CO2 diffuses from pulmonary capillaries to alveoli
  3. Blood leaves high in O2 and low in CO2
134
Q

What happens to oxygen and carbon dioxide partial pressure gradients in the TISSUES?

A
  1. O2 diffuses from capillaries to tissue cells
  2. CO2 diffuses from tissue cells to capillaries
  3. Blood leaves low in O2 and high in CO2
135
Q

As the partial pressure gradients increases, what happens to diffusion?

A

Diffusion also increases

136
Q

What can cause inadequate gas exchange?

A

Increased thickness of the barrier separating the blood and air

137
Q

When thickness increases what happens to the rate of gas transfer?

A

Rate of gas transfer decreases

138
Q

What are conditions that cause the thickness to increase?

A

a. Pulmonary edema
b. Pulmonary fibrosis
c. Pneumonia

139
Q

How much time does blood spend in a capillary?

A

~0.75 second

140
Q

How much time is required for equilibration during O2 gas transfer?

141
Q

How much time is required for blood transit during excercise?

142
Q

What happens to O2 equilibration in diseased states?

A

It is more impaired than CO2 equilibration
-CO2 has a larger diffusion coefficient

143
Q

How is most O2 transported in the blood?

A

It is bound to hemoglobin

144
Q

Hemoglobin + oxygen=____?

A

Oxyhemoglobin

145
Q

Where is a small percentage of oxygen dissolved?

A

The plasma

146
Q

What is the main factor determining the % of haemoglobin saturation?

A

Partial pressure of oxygen in blood

147
Q

The % of haemoglobin saturation is high where the partial pressure of oxygen is ____? and location

A

High
-in the lungs

148
Q

The % of haemoglobin saturation is low where the partial pressure of oxygen is ____?

A

Low
-Tissue cells

149
Q

What happens to oxygen and hemoglobin in tissue cells?

A

Oxygen dissociates from haemoglobin

150
Q

What is the Oxygen haemoglobin dissociation curve?

A

graphical representation of the relationship between the amount of oxygen bound to hemoglobin and the partial pressure of oxygen in the blood
-Not a linear relationship

151
Q

What is the plateau phase of the Oxygen haemoglobin dissociation curve?

A

Where the partial pressure of oxygen is high (lungs)
-Good margin of safety

152
Q

What is the steep phase of the Oxygen haemoglobin dissociation curve?

A

At the systemic capillaries where hemoglobin unloads oxygen to the tissue cells

153
Q

What other factors increase the unloading of O2?

A

Increased CO2
Increased Hydrogen
Increased temperature
2,3 BPG

154
Q

What is 2,3 BPG?

A

Acid produced in RBC with chronically under-saturated hemoglobin
-Altitude living, disease states

155
Q

What is the name of the 2 effects of hydrogen on hemoglobin saturation?

A

Bohr Effect
Haldane effect

156
Q

What is the Borh effect?

A

CO2 produces H+ or other sources of H+ change the pH of hemoglobin molecules

157
Q

What happens when the pH decreases in hemoglobin molecules?

A

More O2 released from hemoglobin
-Hemoglobin saturation curve shifts to the right

158
Q

What is the Haldane effect?

A

Increase in partial pressure pressure oxygen leads to less CO2 bound to hemoglobin
-More CO2 can be carried by hemoglobin during deoxygenated state

159
Q

What three ways does carbon dioxide travel?

A
  1. Physically dissolved
  2. Bound to hemoglobin
  3. as Bicarbonate
160
Q

How is most CO2 transported?

A

As bicarbonate HCO3-
-80%

161
Q

What enzyme facilities the combination of CO2 and water (carbonic acid)?

A

Carbonic anhydrase

162
Q

How is bicarbonate ions formed?

A

Carbonic acid dissociates into hydrogen ions and bicarbonate ion

163
Q

How much of CO2 is transported by hemoglobin?

164
Q

How much of CO2 is dissolved in the plasma?

165
Q

What are conditions that cause abnormalities in arterial P O2 ?

A

Hypoxia
Hyperoxia

166
Q

What is Hypoxia?

A

Condition of having insufficient O2 at the cell level

167
Q

What are the 4 categories of Hypoxia?

A

Hypoxic
Anemic
Circulatory
Histotoxic

168
Q

What is Hypoxic hypoxia?

A

Low arterial PO2 caused by respiratory malfunction or low environmental O2 e.g low altitude, suffocation

169
Q

What is Anemic hypoxia?

A

reduced O2-carrying capacity of the blood despite normal PO2 levels
Causes by: reduced RBC
reduced Hemoglobin
CO poisoning

170
Q

What is circulatory hypoxia?

A

Delivery of O2 to tissues is insufficient
Caused by:
Local (heart attack)
Congestive heart failure
Circulatory shock

171
Q

What is Histotoxic hypoxia?

A

Cells cannot use O2 despite normal O2 delivery
caused by Cyanide poisoning (blocks ETC)

172
Q

What is Hyperoxia?

A

Condition of having an above-normal arterial PO2
Can cause brain problems and retinal damage (possibly blindness)

173
Q

When can Hyperoxia occur?

A

Only when breathing supplemental oxygen

174
Q

What happens if someone with a pulmonary disease with reduced arterial P O2 has Hyperoxia?

A

Can improve their O2 gradient from alveoli to blood

175
Q

What is Hypercapnia?

A

Condition of having excess CO2 in arterial blood
Caused by:
Hypoventilation
Lung disease
-aka Respiratory acidosis

176
Q

What are the conditions that cause abnormalities in arterial P CO2?

A

Hypercapnia
Hypocapnia

177
Q

What is Hypocapnia?

A

Condition of having below-normal arterial PCO2 levels
Caused by:
Hyperventilation (anxiety, fever, aspirin poisoning)
aka Respiratory alkalosis

178
Q

What controls respiration?

A

respiratory centers in the brain stem establish a rhythmic breathing pattern

179
Q

What are the respiratory centers in the brain stem?

A
  1. Medullary respiratory centre
  2. Pneumotaxic centre
  3. Apneustic centre
180
Q

What 2 groupsmis the medullary respiratory centre divided into?

A

a. Dorsal respiratory group (DRG)
b. Ventral respiratory group (VRG)

181
Q

What is the Dorsal respiratory group composed of?

A

Mostly inspiratory neurons

182
Q

what is the Ventral respiratory group (VRG) composed of?

A

Inspiratory and expiratory neurons
-Used when increased ventilation is required

183
Q

What is the pneumotaxic centre?

A

-Sends impulses to DRG that help “switch off” inspiratory neurons –“fine-tuning”
-Dominates over apneustic centre

184
Q

What is the Apneustic centre?

A

-Prevents inspiratory neurons from being
switched off
-Provides extra boost to inspiratory drive

185
Q

What chemical factors play a role in determining magnitude of ventilation?

A

P O2 (peripheral detection)
P CO2 (central detection)
Arterial H+ (pH)

186
Q

What are the peripheral chemoreceptors?

A

Carotid bodies in the carotid sinus
Aortic bodies in the aortic arch

187
Q

Are peripheral chemoreceptors sensitive?

A

No
Hb still at 90% sat at 60mmHg

188
Q

How is a rise in H+ concentration detected?

A

Decrease in pH stimulates ventilation by the carotid chemoreceptors

189
Q

What is the most important regulator of ventilation?

190
Q

What happens to ventilation when PCO2 increases?

A

Respiratory centre is stimulated which increases ventilation

191
Q

What happens to ventilation when PCO2 decreases?

A

Respiratory drive is reduced

192
Q

Where are central chemoreceptors located?

A

Near respiratory centre
responsible for ~70% of ventialtion

193
Q

Generally, an increase in arterial PCO2 triggers?

A

Peripheral/central chemoreceptors and the medullary respiratory centre
—-> Ventilation increases (PCO2 decreases)

Physiology II - HLSC 128 (7 decks)

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