Respiration Flashcards
(260 cards)
1
Q
What are the components of the upper respiratory tract?
A
Nose, pharynx and larynx
2
Q
What are the components of the lower respiratory tract?
A
Trachea, bronchus, lungs
3
Q
What are the 3 parts of the pharynx
A
Nasopharynx, oropharynx, laryngopharynx
4
Q
What components of the pharynx are exposed to both air and food?
A
Oropharynx and laryngopharynx
5
Q
What part of the pharynx is only exposed to air?
A
Nasopharynx
6
Q
What is the surface area of the lungs, and what is it comparable to?
A
100m2, half the size of a tennis court
6
Q
What system is the pharynx apart of?
A
Digestive & respiratory
7
Q
What travels down the pharynx?
A
Air and food
7
Q
What closes the nasopharynx when swallowing?
A
Soft palate
8
Q
What 2 things are essential for efficient gas exchange?
A
Small diffusion distance between air and blood
Large surface area
9
Q
Approximately how many breaths are taken at rest per min?
A
~10/min
10
Q
What is the diffusion distance between the air in the lungs and blood?
A
0.5 micrometers (1/15th of a RBC)
11
Q
Approximately how many litres of air does 1 breath contain?
A
1/2 a litre
12
Q
What is respiration?
A
Exchange of gases
13
Q
What is ventilation?
A
The mechanical movement of air in and out (breathing)
14
Q
What are the 3 types of respiration?
A
External, internal and cellular
15
Q
What is external respiration?
A
Exchange of gasses in the lungs across pulmonary capillaries
15
Q
What does the ventilatory pump include?
A
The diaphragm, rib cage and associated muscles
16
Q
What is internal respiration?
A
Exchange of gasses between blood in systemic capillaries and systemic tissues
17
Q
What is cellular respiration?
A
The process by which individual cells gain energy
18
Q
What is the primary role of the conducting part of the respiratory system?
A
Conduct air and prepare it for exchange by warming, cleaning, and humidifying it
19
Q
What is the primary role of the respiratory part of the respiratory system?
A
Gas exchange
20
Q
What are the 2 functional parts of the respiratory system?
A
Conducting and respiratory
21
Q
What are the conducting airways?
A
Nasal cavities, pharynx, larynx, trachea, bronchi and bronchioles
22
What are the respiratory airways in the respiratory part of the system?
Respiratory bronchioles, alveolar ducts and sacs, and the alveoli themselves
23
What is the process by which cilia clear the conducting airways?
Mucociliary clearance
24
How often do cilia beat?
10-15 times per second
25
What are the 3 requirements for air in order for gas exchange?
Clean, warm (37 degrees), saturated with water
25
In which direction do cilia beat?
Towards the throat
26
How is blood warmed in the nasal cavity?
The very rich blood supply under the epithelium
26
What are the 3 bones in the nasal cavity called, and what do they form?
Turbinate bone forms conchae (superior, middle and inferior)
26
What is the purpose of the Choncae?
Increase surface area (to maximise warming and humidifying)
Swirl air around to create turbulence, throwing particles onto mucous layers
27
Describe the lining of the conducting airways
Pseudostratified ciliated columnar epithelium, goblet cells, basal cells
27
What do paranasal sinuses do?
Lighten face and add resonance to voice
27
What is the temperature of the air by the time it reaches the throat?
~32 degrees
28
What part of the respiratory system slows air down?
Nasal cavity
29
What do seromucous glands secrete and why?
Secrete a watery product to help humidify and filter air
30
What do goblet cells secrete and why?
Secrete a mucin to help humidify and filter air
31
Why is an infection in the lower respiratory tract more dangerous than the upper respiratory tract?
Because it is closer to the blood supply
31
What are the 2 sources of mucous in the respiratory tract?
Mucous glands and Goblet cells
32
What are nose hairs also known as?
Vibrissae
33
What are the overall 3 main functions of the nose?
1. Warm, moisten and filter air
2. Detect olfactory stimuli
3. Modify speech vibrations
33
What is the name of the bone where the olfactory receptor cells are located?
Cribriform plate
33
Name the order of the branches in the respiratory tree
Trachea -> main stem bronchi -> lobar bronchi -> segmental bronchi -> smaller bronchi -> bronchioles -> terminal bronchioles -> respiratory bronchioles -> alveolar ducts -> alveolar sacs
34
How many generations of branching are there in the airways?
28
35
What angle do branches branch off at?
37 degrees
36
What is the main purpose of the branching in the respiratory tract?
Increase surface area
36
How long and wide is the trachea?
12cm long, about as wide as a thumb
36
What 2 things decrease as you go further down the respiratory tract?
Tube diameter and epithelial height
37
What is the shape of the cartilage in the trachea?
C shaped ring
38
What does the cartilage in the trachea do?
Protect the trachea and keep it open
39
What is the widest tube in the respiratory tract?
Trachea
40
What is the name of the muscle connecting the ends of the incomplete cartilage rings in the trachea?
Trachealis muscle
41
What is the role of the trachealis muscle?
Narrow diameter of the trachea - possibly involved with cough reflex if food enters trachea
42
What are the 4 layers of the bronchus?
Respiratory epithelium -> smooth muscle -> mucous & serous glands -> cartilage
42
What is between the cartilage rings in the trachea?
Connective tissue - allows for flexibility
43
What is the shape of cartilage in the bronchus?
Crescent moon-shaped (not as big as C)
44
What cells do bronchiole have instead of goblet cells?
Club cells
45
What do club cells do?
Secrete watery substance to prevent walls from sticking together during expiration
Secrete chemicals to break down bacteria
46
Describe the walls of bronchioles
simple columnar or cuboidal epithelia with club cells on top of smooth muscle
47
Where is the site of major broncho-constriction?
Bronchioles
48
What is the difference between terminal and respiratory bronchioles?
Respiratory bronchioles have alveoli buds
49
What is the final branch of the conducting zone?
Terminal bronchioles
50
What is the first branch of the respiratory zone?
Respiratory bronchioles
51
What generation of branching forms bronchioles?
16th
52
What is the final branch of the respiratory zone?
Alveolar sacs
53
What is an alveolar sac?
More than 2 alveoli in an area
54
What are the 2 types of alveolar cells?
Type 1: Pneumocytes
Type 2: Surfactant cells
55
Describe type 1 alveolar cells
Squamous epithelium
55
What is the purpose of type 2 alveolar cells?
Reduce surface tension, preventing alveolar collapse
56
What is the 3rd type of alveolar cell, and what does it do?
Alveolar macrophage - picks up and destroys debris that the conducting system has failed to filter
57
What is the final line of immune defence in the lungs?
Alveolar macrophage
58
Describe the order in which oxygen must pass through to get from the lungs to the blood
Lumen of alveolus -> type 1 pneumocyte cytoplasm -> fused basement membrane of Type I alveolar cell and endothelial cell -> cytoplasm of capillary endothelium -> blood plasma -> RBC
59
How many lobes does the right lung have?
3
60
How many lobes does the left lung have?
2
61
What is the name of the region in which arteries, veins and bronchi enter each lung?
Hilum
62
What is the name of the bronchi supplying each lobe?
Lobar bronchi
63
What is the name of the bronchi supplying each lung?
Main stem bronchi
64
What is the name of the bronchi supplying each segment?
Segmental bronchi
65
How many segments are in the left lung?
8
66
How many segments are in the right lung?
10
67
What are the 3 factors affecting pulmonary ventilation?
Surface tension, lung compliance, airway resistance
68
Is expiration active or passive?
Passive
68
Is inspiration active or passive?
Active
69
What percentage of air movement into and out of the lungs is the ribcage responsible for?
25%
70
What muscles are involved with inspiration and what do they do?
External intercostal muscles - contract during inspiration to lift ribs upwards
71
What muscles are involved with expiration and what do they do?
Internal intercostal muscles - usually not contracting - only contract during forceful exhalation to drag ribs downwards
72
What is the relationship between volume and pressure?
Volume is inversely proportional to pressure (e.g. as volume increases pressure decrease)
73
What does contraction of the diaphragmatic muscle do, and when does this occur?
Flatten the diaphragm, pulling it down - increasing the volume of the thorax during inspiration
74
What percentage of the bulk flow of air is the diaphragm responsible for during quiet breathing?
75% (this decreases during exercise)
75
What is VT?
Tidal volume - the volume of air per breath at rest ~0.5L
76
What is FRC?
Functional residual capacity - the amount of air in the lungs after passive expiration (~1.8L - 2.4L)
77
What is VR?
Residual volume - the volume of air in the lungs that cannot be expelled ~1/2 FRC
78
What is ERV?
Expiratory Reserve Volume - the extra air exhaled forcefully on top of VT - (FRC-VR)
79
What is IRV
Inspiratory reserve volume - additional air inhaled on top of VT
80
What is the calculation for ventilation (L/min)?
VT x Respiratory Frequency
81
What is FEV1?
Forced expiratory volume - the volume of gas exhaled in 1 sec during forced exhalation
82
What is FEC?
Maximum expiration after maximum inhalation
83
How is the visceral pleura attached to the lungs?
Surface tension
84
When are the forces on the chest wall and forces on the lungs balanced?
At FRC
85
What is the equation for residual volume?
TLC - VC
86
What is the approximate dead space in a healthy person?
150ml
87
What would you expect the pleural pressure to be after a pneumothorax?
0mmHg
88
Where is total resistance the largest?
Segmental Bronchi
89
Where is total resistance the lowest in the respiratory tract?
Bronchioles
90
What is the equation for calculating lung health?
FEV1/FVC
91
What is the normal/healthy percentage for FEV1/FVC?
80%
92
What is used to measure gas volume dynamics (FEV1/FVC)?
Vitalograph
93
What is VE, and how is it calculated?
Minute ventilation - VT x F or VA + VD
94
What is the VE for hyperventilation?
>6L/min
95
What is the VE for hypoventilation?
<6L/min
96
What is VA, and how is it calculated?
Alveolar ventilation - VT-VD x f
97
What is used to measure lung volumes?
Spirometer
98
What happens to pleural pressure during inspiration?
Becomes more negative
99
What happens to pleural pressure during expiration?
Becomes less negative
100
What is the most important respiratory muscle?
Diaphragm
101
What percentage of VT does VD represent?
30%
102
What shape is the diaphragm when relaxed?
Dome
103
What are the 2 equations for compliance?
△V/△P & 1/elasticity
104
What is La Place's Law?
P = 2T/R
105
What two things affect compliance?
Amount of elastic tissue in the lungs & amount of surfactant in the alveoli
106
What percentage of total lung capacity does anatomical dead space make up?
3%
107
What is the effect of sympathetic stimulation on the lungs?
Bronchodilation
108
What are the receptors in the smooth muscle of bronchioles called for sympathetic nerves?
Beta2-adrenoceptors
109
What is the effect of parasympathetic stimulation on the lungs?
Bronchoconstriction
110
What are the receptors in the smooth muscle of bronchioles called for parasympathetic nerves?
Muscarinic Receptors
111
What is the reflex that controls bronchodilation called?
Hering-Breuer Reflex
112
Describe the Hering-Breuer Reflex
Inhalation -> stretch of mechanoreceptors in bronchioles -> increased vagus nerve stimulation to resp. centre in medulla -> increased sympathetic stimulation of Beta2-adrenoceptors on bronchioles -> bronchodilation
113
What is HP?
Hydrostatic pressure
114
What is Pa?
Pulmonary blood pressure
115
What is PV?
Arterial venous difference
116
What is PA?
Alveolar pressure
117
What is Q?
Cardiac output
117
What is HP the same as?
Pa
118
What makes the lungs have elasticity?
Collagen and elastin fibres
119
What is the capacity of the resting position of the lung?
Functional residual capacity
120
Why is a highly compliant lung bad?
High compliance means low elasticity, so expiration will require a lot of effort (no longer be passive at rest)
121
What device is used to measure pressures inside different areas of the lungs?
Manometer
122
How many times do the airways divide?
23
123
Describe the flow of air in the conducting zone
Fast and turbulent
124
Describe the flow of air in the respiratory zone
Slow and laminar
125
How much less resistance is there in the respiratory bronchioles/smaller airways than in the trachea?
500x less
126
Describe the arteries and veins of pulmonary circulation
Thin-walled, low-pressure, small amount of smooth muscle, lots of branching decreasing resistance, highly compliant
127
Why is it necessary to have slow and laminar airflow in the alveoli?
Provides time for gas exchange
128
How is mean blood pressure calculated?
Diastolic p + (1/3 systolic p - diastolic p)
129
What is the mean pulmonary BP?
14 mmHg
130
What is the mean systemic BP?
93 mmHg
131
What is the benefit of sheet blood flow?
Increased surface area for gas exchange due to increased contact between blood and alveoli
132
What does hypoxia in an alveoli cause?
Vasoconstriction
133
What could hypoxia in alveoli be due to?
Bronchoconstriction e.g. asthma, pollen
134
What part of the lung receives the most blood supply and why?
The bottom, due to gravity
135
Why is VA/Q not 1?
The lungs are not fully perfused and ventilation is higher at the base of the lungs
136
What does an increase in blood flow and pressure to the lungs result in (in terms of gas in blood)?
Increased O2 in blood as the top of the lungs are recruited
137
What are the 5 factors affecting gas exchange?
Area, thickness of tissue, partial pressure differences, solubility of gas, molecular weight of gas
138
What is the diameter of alveoli?
0.3mm
139
How many times more soluble is CO2 compared with O2?
25 times
140
What is a small △P with a larger △V indicate?
High compliance
141
What disease results in low-compliant lungs?
Fibrosis
141
What is COPD the result of?
Smoking - causes reduced elastic fibres and an overinflated lung at rest
141
What disease results in highly compliant lungs?
COPD - chronic obstructive pulmonary disorder
142
What is the drug that asthmatics take?
Salbutamol
143
Describe fibrosis
Stiff lungs due to build up of pathogens (e.g. coal), deflated lungs, widened mid-sternal space and fluffy areas of fibrotic tissue (typically at base)
144
What are some of the effects of fibrosis on a patient?
Increased effort required to inflate lungs
145
Describe COPD
Expanded lungs, barrel chest, flattened diaphragm, reduced mid-sternal space
146
Where are ventilation and perfusion the lowest?
Apex of the lung
147
Where are ventilation and perfusion the highest?
Base of the lung
148
Where is the alveoli volume the largest?
Apex of lung
149
Explain the differences in negative pressures in the intrapleural space
The apex of the lung has a more -ve intrapleural pressure due to gravity, resulting in a larger pleural space at the apex and hence smaller (more -ve) lressure. Pleural space at base of lung is smaller, resulting in a less negative intrapleural pressure
150
What is the cause of pulmonary hypertension?
Hypoxia
151
What is hypoxia?
Low O2 in lungs
152
What follows hypoxia in an alveoli?
Vasoconstriction
153
Describe how pulmonary hypertension is caused, and how it can cause right heart failure.
Hypoxia -> vasoconstriction -> increased pulmonary artery resistance and ∴ BP -> increased afterload on RV -> RV becomes stretched, baggy and weak -> RV failure
154
Describe how pulmonary oedema may be caused and what it results in
Blood clot or atheromas in LV -> LV not pumping properly -> increased congestion and BP in pulmonary veins -> oedema -> reduced lung compliance and reduced gas exchange -> breathlessness (dyspnoea) -> systemic hypoxia
155
What is breathlessness also known as?
Dyspnoea
156
What is hypoxemia?
Low O2 in blood
157
What is the effect of hyperventilation on CO2 levels?
Decrease
158
What is the effect of hypoventilation on CO2 levels?
Increase
159
What is the effect of hypoventilation on O2 levels?
Decrease
160
What may increased CO2 result in?
Acidosis
161
What may decreased CO2 result in?
Alkalosis
162
What does a sudden increase in pulmonary arterial pressure result in?
Recruitment of previously closed vessels and distension of the lumens of already patent vessels
163
When is the ventilation: perfusion ratio less than one?
What there is more perfusion than ventilation
164
Where is the ventilation: perfusion ratio the highest?
The apex of the lung
165
Where is the ventilation: perfusion ratio the lowest?
The base of the lung
166
What are 4 consequences of pulmonary hypertension?
Increased pressure in pulmonary capillaries
Fluid movement into alveoli
Pulmonary oedema
Breathlessness
167
What are the lung segments called?
Bronchopulmonary segments
168
How many segments are in the right lung?
10
169
How many segments are in the left lung?
8
170
Each lung segment has its own...
Blood and air supply
171
What is normal breathing also called?
Eupnoea
172
What is the expected Hb saturation % at pO2 40mmHg?
75%
173
What is the effect of exercise on pH?
Decrease in pH
174
How is the majority of CO2 transported in blood?
Conversion to bicarbonate ion
175
What would excitation of the phrenic nerve lead to?
Contraction of the diaphragm and increased thorax volume
176
What would a decrease in pH lead to?
Increased ventilation
177
What is Eupnoea?
Normal breathing
178
What is no breathing called?
Apnoea
179
What is apnoea?
No breathing
180
What is the sensation of breathlessness called?
Dyspnoea
181
What is dyspnoea?
Sensation of breathlessness
182
What is asphyxia?
Deprivation of oxygen
182
What is no oxygen called?
Anoxia
182
What is anoxia?
No oxygen
183
What is deprivation of oxygen called?
Asphyxia
184
What is hypercapnia?
High CO2
185
Why is low CO2 called?
Hypocapnia
186
What is high CO2 called?
Hypercapnia
187
What is hypocapnia?
Low CO2
188
What is ischaemia?
Inadequate blood supply to an organ
189
What is inadequate blood supply to an organ known as?
Ischaemia
190
What has the largest impact on the direction of gas flow?
Pressure differences
191
What is the effect of hyperventilation on pO2 and PCO2?
Increased pO2 and decreased pCO2
191
What 2 main things affect compliance?
Elastic tissue and surfactant
192
How many heme groups are in hemoglobin and myoglobin?
4 & 1
193
What is the relationship between temperature and gas solubility?
Inverse relationship, solubility increases as temperature decreases.
194
What has the greatest effect on the ability of blood to transport O2?
Amount of Hb
194
What is the effect of higher temperatures on Hb-O2 affinity?
Decrease in affinity
195
What is the concentration of O2 in plasma directly proportional to?
Its partial pressure
196
What two things does an increase in SV do to pulmonary veins/capillaries?
Increased distension and recruitment
197
What would occur if lung capillaries did not distend and recruit with increased blood?
Oedema
198
What is the purpose of the Cl- shift?
Maintains cellular electroneutrality
199
What are the 2 ways in which oxygen is transported in the blood?
Binds with Hb and dissolves in plasm
200
What gas is diffusion limited?
CO2
201
What gases are perfusion limited?
O2 and NO2
202
How does the affinity of Hb-O2 change with pO2's?
Decrease in pO2 = decrease in affinity - needed for association in lungs and dissociation at tissues
203
What is the Bohr effect?
A shift of the O2 dissociation curve to the right due to increased H+, CO2, temp, DPG or low O2 in tissues - represents decreased affinity of Hb to O2
204
What is the Haldane effect?
A shift of the O2 dissociation curve to the left due to decreased H+, CO2, temp, DPG or high O2 in tissues - represents increased affinity of Hb to O2
205
What are the four ways CO2 may be transported in the blood?
Dissolved
Converted to HCO3-
Combined with amine groups
As H2CO3 and CO3- ions
206
What transports Cl- and HCO3- across the RBC membrane?
Antiporter
207
Why is the conversion of CO2 to HCO3- faster in RBC?
They contain the enzyme carbonic anhydrase
208
Describe the affinities of Hb and HbO2 for CO2
Hb - higher affinity for CO2
HbO2 - lower affinity for CO2
209
What syndrome may occur if your chemoreceptors fail?
Congenital hypoventilation syndrome
210
Where are the PNS chemoreceptors located?
Aortic and carotid bodies
211
What nerves connect the PNS chemoreceptors and the medulla?
Vagal (aortic) and glossopharyngeal (carotid) (X & IX)
212
What are the stimulants of PNS chemoreceptors?
Low O2, H+, high CO2 (mainly high CO2), increased SNS activity
213
What is the response time of PNS chemoreceptors?
Fast - within 1 breath
214
What is the response time of the CNS chemoreceptors?
Slow ~30 sec
215
What is the reflex response of the PNS chemoreceptors?
Increased breathing rate and depth of breathing
216
Where are CNS chemoreceptors located?
Neurons and Astrocytes <0.5mm beneath the surface of the ventral medulla
217
What is the main stimulant of CNS chemoreceptors?
H+ ions
218
Do CNS chemoreceptors respond to O2 levels?
No
219
Why is the response time of CNS chemoreceptors slow?
Because only CO2 can cross the BBB, and CSF contains limited carbonic anhydrase, so the conversion of CO2 to H+ is slow
220
What is the reflex response of CNS chemoreceptors?
Increased minute ventilation
221
What type of binding is O2-Hb?
Co-operative
222
What are the effectors of the respiratory centre in the medulla?
Respiratory muscles
223
What are the units for peak flow rate?
L/min
224
What are the units for dry spirometry?
mL
225
What are the units for dry spirometry?
mL
225
Would an asthmatic have a higher or lower peak flow rate than a normal person?
Lower due to increased airway resistance
226
What does wet spirometry measure?
Tidal volume
Inspiratory reserve volume
Expiratory reserve volume
Vital capacity
227
What does dry spirometry measure?
Forced vital capacity & Forced expiratory volume
228
How would an asthmatic's FEV1 differ from that of a healthy individual?
Reduced
229
What does the downward movement of liquid in the outer arm of a manometer indicate?
Negative pleural pressure
230
What is the intrapleural pressure in the box lung model when no force is being applied?
0 cm H20
231
How does the content of the intrapleural space in the lung model differ from real lungs?
Air in lung model is expandible, serous fluid in human is not expandable
232
What 3 factors affect peak flow rate between individuals?
Age, sex and height
233
What is Dalton's law?
In a mixture of gases each gas exerts its own partial pressure
234
What is Boyles law?
At a constant temp, volume of gas varies inversely with pressure
235
What is the difference between lung volumes and lung capacities?
Volumes are measured and capacities are calculated
236
What does La Places law measure?
Surface tension induced pressure in Alveoli
