Chapter 13 - Respiratory Flashcards
(206 cards)
1
Q
What is the function of transmural pressure gradient
A
Creates a balance allowing lungs to stay inflated
-negative pressure
-lungs are partially inflated always (energy efficient)
2
Q
Lungs are highly distensible meaning what?
A
-elastic recoil
-inflate and deflate
3
Q
Thoracic wall is more rigid and recoils what direction
A
Recoils outward
4
Q
Transmural pressure gradient keeps what two things together
A
Lung and chest wall
5
Q
Lungs elastic recoil depends on what two factors
A
-elastic connective tissue
-alveolar surface tension
6
Q
Elastic connective tissue
A
Stretchability, recoil back to original state
7
Q
Alveolar surface tension
A
Thin liquid that lines each alveolus
-stops drying out
8
Q
Surface tension
A
The action of alveoli radius decreasing-
water molecules coming closer together
9
Q
The smaller the structure the greater the
A
Surface tension
10
Q
Lungs tend to collapse down to small structures due to
A
Surface tension
11
Q
Pulmonary surfactant
A
-comes from alveolar type 2 cells
-lines alveoli and reduces
surface tension of the liquid
-reduces work of the lungs
12
Q
Water lined alveoli creates
A
Surface tension
13
Q
Greater the surface tension
A
More likely to collapse
14
Q
What increases secretion of type 2 cells
A
-deep breathing (stretch)
15
Q
A lack of surfactant example
A
Babies born prematurely
-IRDS/RDSN
-lungs just collapse and need to reinflate (huge energy drain)
16
Q
Alveolar interdependence
A
-depends on alveolar structure (closer is better)
-neighbouring alveoli (physically connected) resist collapse stretch by recoiling
“Tug of war”
17
Q
Forces keeping alveoli open
A
-positive transmural pressure
-pulmonary surfactant
-alveolar interdependence
18
Q
Forces promoting alveolar collapse
A
-elasticity of stretched connective tissue fibres
-surface tension
19
Q
Pneumothorax
A
-with no opposing negative pleural pressure to keep it inflated, lung collapses to its un stretched size
20
Q
Decreased volume =
A
Increased pressure
21
Q
Increased volume =
A
Decreased pressure
22
Q
Boyles law
A
The pressure exerted by a gas varies inversely with the volume of gas
23
Q
Boyles law calculation
A
P= (1/V)
24
Q
Changes in alveolar pressure produce
A
Flow of air into and out of the lungs
25
If alveolar pressure is less than atmospheric pressure…
Air enters the lungs
26
If alveolar pressure is greater than atmospheric pressure
Air exits from the lungs
27
Boyles law calculation 2
P1v1 = p2v2
28
Volume of lungs is made to
Change
29
By altering lung volume
-pressure changes in the lungs
-air flow is generated
30
What changes the volume of thoracic cavity
Respiratory muscle activity
-diaphragm
31
What is the major inspiration muscle
Diaphragm
32
Diaphragm movement to draw in air (inhale)
Contraction
-increases volume
33
Diaphragm action for expiration
Relaxes
-dec volume
34
Elastic recoil
Surface tension and elastin
35
Processes of inspiration
1.Muscle activity
2. Thoracic cavity inc
3. Pressure alveoli dec
4. Air flow inc
36
Processes of expiration
1. Muscle activity
2. Decreased thoracic cavity
3. Increased pressure alveoli
4. Decreased air flow
37
Expansion during inspiration ___ the intrapleural pressure
Decreases
38
Increased volume lowers what
The intra alveolar pressure below atmospheric pressure
39
Air flow dependent on (two things)
-pressure differences
-airway resistance
40
Airflow calculation
F=(change in)P/R
41
Greater R, the ____ F
Lesser/decrease
42
Greater (change in)P, ____ in F
Greater
43
What controls contraction of smooth muscle in airway walls
Autonomic ns
44
SNS causes
Bronchodilation
-NE
-E
45
PNS causes
Bronchoconstriction
-ACH
46
Disease states and respiration
-narrows airways
-flow restricted and have to work harder to breathe (inc pressure and inc resistance)
47
Diseases affecting airway resistance
-asthma
-chronic bronchitis
-emphysema
48
Chronic pulmonary disease
Increases airway resistance
49
During an increase of airway resistance
Expiation is more difficult than inspiration
50
Asthma
Increased smooth muscles
-inflammation and histamine
-breathing out is problem (expiration) (wheezing)
51
COPD
Chronic obstructive pulmonary disease
-always experienced
-constricts airflow
-inflammatory
-commonly caused by cigarette smoke
52
Chronic bronchitis
COPD disease
-long term inflammatory of smaller airways
-edematous thickening
-coughing doesn’t help
53
Emphysema
COPD
-collapse and breakdown of smaller airways
54
Spirometer
Air filled drum floating in a water filled chamber
55
Spirometer
Air filled drum floating in a water filled chamber
56
Max volume male lung
5.7L
57
Max volume of lungs female
4.2L
58
At rest, lungs contain ___ after expiration
2.2L
-still half full
59
Vital capacity
Max inspiration, max expiration
-exercising to max capacity
60
Tidal volume
Volume of air entering or leaving lungs during a single breath
61
Residual volume
Minimum volume of air remaining in the lungs even after a maximal expiration
62
Total lung capacity
Maximum volume of air that the lungs can hold
63
Inspiratory reserve volume (IRV)
Extra volume of air that can be maximally inspired over and above typical resting tidal volume
64
TLC =
VC + RV
65
Average value of TLC
5700
66
Average value of VC
4500
67
Average value of TV
500
68
Average value of RV
1200
69
FEV
Forced expiratory volume in one second
70
Obstructive lung disease
Increased airway resistance
FEV <80%
71
Restrictive lung disease
Normal airway resistance but reduced vital capacity
-impaired respiratory movements
72
Pulmonary ventilation =
Tidal volume x respiratory rate
73
Pulmonary ventilation
Measures how much air moves (out) into the lungs per minute
74
Anatomic dead space
Area not taking part in gas exchange
-150ml
75
Alveolar ventilation calculation
=(tidal volume - dead space) x respiratory rate
76
Alveolar ventilation
-the air exchanged between atmosphere and alveoli per minute
-more important
77
When expirating what is the first bit of air that comes out
Anatomical dead space air
78
Work of breathing
Requires 3% of total energy
-can be increased
79
Pulmonary compliance is decreased causes
Increased work of breathing
80
Airway resistance is increased (COPD)
Work of breathing is increased
81
elastic recoil is decreased causes
Increased work of breathing
82
Internal respiration
Biochemistry inside cells
-mitochondria, ATP
83
External respiration
Exchange of O2 and CO2 between external environment and cells of the body
84
Lungs
-each supplied by one bronchi
-contains elastic material
85
Bronchioles
-no cartilage
-smooth muscles (ans)
-sensitive to hormones and chemicals
86
Alveoli are crusted where
At ends of terminal bronchioles
87
Convection zone
Trachea and larger bronchi
-purely functional transportation
88
Diffusion zone
Bronchioles and alveoli
-site of gas exchange
89
Trachea and larger bronchi
-rigid, non muscular tubes
-rings of cartilage preventing collapse
90
Alveoli
Thin walled inflatable sacs
-gas exchange
-large surface area
91
Walls of alveoli consist of a single layer of flattened epithelial cells called:
Type 1 alveolar cells
92
Each alveolus is incircled by
Pulmonary capillaries
93
Type 2 alveolar cells secrete
Pulmonary surfactant
94
Pores of kohn
Permit airflow between adjacent alveoli
95
Diaphragm
-dome shaped sheet of skeletal muscle
-innervated by phrenic nerve
96
External intercostal muscles are innervated by ___ nerve
Intercostal
97
Major muscle of respiration
Diaphragm
98
Inspiration requires
Contraction of muscles
99
Expiration requires
Relaxation of muscles
100
Pleural sac
Double walled closed sac separating each lung from thoracic wall
-friction
-GI movement
101
Pleural cavity
Interior of plural sac
102
Intrapleural fluid
-secreted by surfaces of pleura
-lubricate pleural surfaces
103
Layers of lung starting from thoracic wall going inwards
-parietal pleura
-pleural sac (intrapleural fluid)
-visceral pleura
-lung
104
F=
(Change in)P/R
105
How do we get air in and out of the lungs
Respiratory mechanics
106
Respiration mechanics
-pressure inside and outside
-pressure differences
107
Four different pressure considerations that are important in ventilation
-atmospheric
-(intra)alveolar
-(intra)pleural
-transpulmonary
108
Transpulmonary pressure is calculated by
Inside pressure - outside pressure
109
Respiratory pressure is always relative to
Atmospheric pressure
110
Sea level pressure (mmHg/atm/cmH20)
-760mmHg
-1atm
-1034cmH20
111
Higher altitudes
Less pressure
-gas molecules further apart
112
Atmospheric pressure
Exerted by the weight of the air in the atmosphere on objects
113
Atmospheric pressure ___ with ___ altitude
Decreases with increasing
-PB
114
Alveolar pressure
The pressure within the alveoli
-PA
115
Pleural pressure
Pressure outside the lungs but within thoracic cavity
-Ppl
116
Transpleural pressure gradient
Inside pressure minus outside pressure
117
Is pleural pressure greater than or less than alveoli
Always less than
118
Why is pleural pressure less than alveoli pressure
Keeps lungs and rib cage together in movements while breathing
119
Gas exchange
Simple diffusion of o2 and co2 down partial pressure gradients
120
Partial pressure gradients
-gases
-high partial pressure flows to lower partial pressure
121
Partial pressure equals
(Total pressure) x (fractional composition)
122
Percentage of N2 out of total atmospheric pressure
79%
123
How to determine partial pressure of element in air
(Percentage) x (total in mmHg) = partial pressure of element
124
Gases can dissolve in
Liquid
-don’t neccesarily form bubbles
125
Partial pressure of alveoli
100mmHg
126
Percentage of o2 compared to TAP
21
127
Partial pressure of o2
160
128
Why is alveolar Po2 100 mmHg and not 160mmHg
-every time you take a breath, you are saturating air with watervapor
-dilutes all gases by 47 mmHg
129
Total atmospheric pressure =
760 mmHgq
130
Po2 =
(Inspired gas)
150 mmHg
131
Humidification + small turnover =
100 mmHg
132
Fresh alveolar air is mixed with what,
A large volume of old air remaining in lungs
-from dead space at end of expiration
133
functional residual capacity
2.2L
134
Movement of oxygen is completely independent of
Movement of carbon dioxide
135
Venous blood entering the lungs: low in ___, and high in ____
O2, CO2
136
(Blood entering the lungs)
Alveolar Po2:
Alveolar Pco2:
why?
-high
-low
Because only a portion of alveolar air is replaced by fresh atmospheric air during each breath
137
Partial pressure gradient for o2
100-40= 60mmHg
138
Partial pressure gradients for co2
46-40= 6mmHg
139
Due to the partial pressure gradients for o2 and co2 between alveoli and pulmonary capillary blood, what takes place
-o2 is 60, co2 is 6
Cause o2 to diffuse into blood, and co2 to diffuse into the alveoli (out of the blood)
140
The greater the partial pressure=
Into the blood to equilibrium
141
Blood leaving the lungs has
High partial pressure
-high content of o2
-low content of co2
142
O2 diffuses from
(Lungs)
Alveoli to pulmonary capillaries
143
Co2 diffuses from
(Lungs)
Pulmonary capillaries to alveoli
144
O2 diffuses from (tissues)
Capillaries to tissue cells
145
Co2 diffuses from (tissues)
Tissue cells to capillaries
146
Influence of: partial pressure gradients of o2 and co2
Inc diffusion with inc partial pressure gradient
147
Influence of: surface area of alveolar capillary membrane
Inc diffusion with inc surface area
148
Influence of: thickness of barrier separating the air and blood across alveolar capillary membrane
Diffusion dec as thickness inc
149
Influence of: diffusion coefficient (solubility o of the gas in membrane)
Diffusion inc with coefficient inc
150
Surface area of gas exchange: comparing normal and emphysema
Emphysema will be expanded
151
When does inadequate gas exchange occur
-thickness of barrier that separates air and blood is pathological increased (emphysema)
152
Thickness increases
Rate of gas transfer dec
153
Blood spends roughly ___ sec in capillary
0.75
154
Gas transport in lungs
Hemoglobin + o2 —> oxyhemoglobin
-small percentage of o2 dissolved in plasma
155
Gas transport in tissues
Oxyhemoglobin —> hemoglobin + o2
-oxygen leaves capillaries and enters tissue cells
156
what is haemoglobin saturation stats
Amount of O2 attached to Hb
157
What does Hb sat depend on
P02
158
Amount of P02 and PC02 in pulmonary/systemic arteries
P02–> 100
PC02–> 40
159
Amount of P02 and PC02 systemic/pulmonary veins
P02–> 40
PC02–> 46
160
Hb in RBCs of the arteries
98%
161
Hb in RBCs in capillaries
75%
162
Partial pressure of oxygen in blood
Is the main factor determining the percentage of haemoglobin saturation
163
%Hb saturation is high when.. (pressure o2)
Pressure of oxygen is high
-lungs
164
%Hb saturation is low when… (pressure of oxygen)
Pressure of oxygen is low
-tissue cells
165
What is the important of a plataeu phase when graphing O2 saturation
Gives a good margin of safety
166
Where is the steep phase when graphing O2 saturation
Found in systemic capillaries, where Hb unloads oxygen to the tissue cells
167
Alveolar P02 = blood P02
Equal amount of free floating oxygen in blood and alveoli
168
Alveolar P02 > blood P02
There are more free floating oxygen in the lungs compared to haemoglobin molecules
169
What are other influences on the )2-Hb curve
-PC02
-Acid (H+)
-temperature
-2,3 bisphospoglycerate
170
Unloading of 02 is increased by
Increased: CO2, H+, temperature
-2,3 BPG
171
Bohr effect
CO2 producing H+ and other sources of H+ (lactic acid)
-decreased pH—-> more o2 released from Hb
172
Haldane effect
Increase in P02 leads to less CO2 bound to Hb
-inc capacity for Hb to carry CO2 in a deoxygenated state
173
Carbon dioxide travels in three ways
-physically dissolved
-bound to haemoglobin
-bicarbonate
174
Most CO2 is transported as
Bicarbonate ion
-HCO3
175
CO2 combines with water to form (using what enzyme)
Carbonic acid
-carbonic anhydrase
176
Carbonic acid
H2CO3
177
Carbonic acid turns into
H+ + HCO3-
178
10% of the CO2 is bound to
Hb in the blood
179
10% of the transported CO2 is
Dissolved in the plasma
180
Lungs vs tissues
Lungs: product is CO2 and H20
Tissues: product is H+ and HCO3-
181
Chloride shift
Occurs in tissues
-exchange of Cl- (in) for HCO3- (out)
182
Hyperventilation
Inc pulmonary ventilation in excess of metabolic requirements
-decreased PCO2 and H+
183
Hypoventilation
Under ventilation in relation to metabolic requirements
-inc PCO2 and H+
184
Hypoxia
Insufficient oxygen at cellular level
185
Hyperoxia
Condition of having an above normal arterial PO2
186
Hypercapnia
Having excess CO2 in arterial blood
-caused by respiratory acidosis
187
Hypocapnia
Below normal arterial PCO2 levels
-respiratory alkalosis
188
Function of respiratory centres in brain stem
Establish rhythmic breathing pattern
189
Medullary respiratory center two aspects
-dorsal respiratory group
-ventral respiratory group
190
Pneumontaxic centre
Impulse to DRG to switch off inspiritory neurons
191
Apneustic centre
Prevents inspiratory neurons from being switched off
-keep on
-extra boost for inspiratory
192
____ dominates over ____ (control of repiration)
Pneumotaxic > apneustic
193
Chemical factors that assist in breathing
-PO2
-PCO2
-arterial H+
194
Chemical factors aid in
Determining magnitude of ventilation
-inc breath/depth of breath
195
Peripheral chemoreceptors
Carotid bodies, aortic bodies
196
Peripheral chemoreceptors are
Not sensitive
197
Arterial pH effect on ventilation
Peripheral H+ detects non respiratory sources
-lactic
198
Rise in arterial H+ concentration
-decrease in pH
Increases ventilation
-carotid
199
CO2 + H2O —->
H2CO3
200
H2CO3 —->
H+ + HCO3-
201
Increase of PCO2
Increase ventilation
202
Decrease in PCO2
Reduce respiratory drive
203
Increase in PCO2
Increase in brain ECF PCO2
-increases CO2 and H2O to inc H+
204
Increase in brain ECF H+
Increases central chemoreceptors/medullary respiratory centre
205
Inc central chemoreceptors, and medullary respiratory centre
Increase ventilation
206
Increase ventilation
Decreases arterial PCO2
