Respiratory Physiology Flashcards
1
Q
Respiration controls…
A
- CO2 supply
- O2 supply
- H+ ion concentration
2
Q
What is the outer form of respiration?
A
- Gas exchange: outside world → Blood
- Take-up + transmission of oxygen by cells
- CO2 elimination
- Gas exchange
3
Q
Inner form of respiration
A
Gas exchange: Blood → Cells
4
Q
99% of pulmonary blood supply comes from…
A
A. pulmonalis
5
Q
99% blood leaves the lung via…
A
Vv. pulmonales → Left atrium
6
Q
Which vessels represent the ‘dual blood supply’ of lung circulation?
A
- A. pulmonalis (Functional)
- A. bronchiales (Nutritive)
7
Q
1% of pulmonary blood supply comes from…
A
Aa. bronchiales (Oxygenated)
8
Q
Venous blood contaminates refreshed blood via …
A
V. bronchiales
9
Q
What transfers deoxygenated blood from the right ventricle to the lung?
A
A. pulmonales
10
Q
From the aorta, …transfers oxygenated blood to the lungs
A
A. bronchiales
11
Q
Automatically decreased perfusion to certain areas of the lung leads to…
A
Redirection of blood to well-ventilated lung territories
12
Q
Describe the physiology of blood redirection in the lung
A
Hypoxia causes vasoconstriction
13
Q
A small portion of blood goes directly to the right atrium via…
A
V. azygos
14
Q
Where does venous blood contaminate oxygenated blood?
A
- V. bronchiales
- Coronary vessels
15
Q
Blood stays in the capillaries for…during 1 cardiac cycle
A
800 msec
16
Q
O2 and CO2 diffusion takes how long to occur?
A
250 msec
17
Q
A
pO2 (mmHg)
18
Q
A
pCO2 (mmHg)
19
Q
Unit for airflow
A
Va/min
(Ventilation, litre air/ min)
20
Q
Airflow is proportional to…
A
Perfusion of blood
21
Q
Unit for perfusion of blood (Q)
A
litre/min
22
Q
Normally: Va/Q =
A
1
23
Q
In normal conditions, blood will flow away…
A
Arterialised (oxygenated)
24
Q
When the alveolus is plugged…
A
- Va = 0
- Va/Q = 0
- Blood flows away deoxygenated
25
Capillary plug
When blood flow stops
26
In the incidence of capillary plug...
* Q=0
* Va/Q = ∞
* Alveolar gas pressure = atmospheric pressure
27
Degree of perfusion
Perfusion absent
28
Degree of perfusion
Perfusion is sporadic
29
Degree of perfusion
Perfusion is constant
30
Describe the effects of gravity in zone 1 of the lung
* Pressure in alveoli compresses blood vessels
* Perfusion decreases
* PA \> Pa\> Pv
31
Describe the effects of gravity in zone 2 of the lung
* Alveolar capillaries are open during systole
* Closed during diastole
* PA\>Pa\>PV
32
Describe the effects of gravity in zone 3 of the lung
* Gravity increases BP
* Alveolar pressure can't compress capillaries
* During diastole and systole
* PA\>PV\>Pa
33
PA=
Alveolar pressure
34
Pa=
Arterial pressure
35
PV=
Venous pressure
36
Which innervation causes pulmonary vessels to enlarge
Parasympathetic *(n. vagus)*
37
Which innervation causes pulmonary vessels to constrict?
Sympathetic, noradrenergic fibres
| (Through α-receptors)
38
Effect of adrenalin on pulmonary circulation
* Creates intensive alveolar dilation (through β-receptors)
* Increased ventilation
* Crucial for anaphylaxis counteraction
39
Local hypoxia in the lungs causes...
Local stenosis → Blood redistribution
40
The effect of BP increase on pulmonary circulation
* Decreased vascular tone
* Affects the ability to achieve _extremely high minute volume_
41
How does the nasal ciliated cylindrical epithelium + blood vessels play a role in _organism defence_?
* Mechanically:
* Mucous motion
* Coughing
* Immunologically
* IgA
42
How does the nasal ciliated cylindrical epithelium + blood vessels play a role in _air conditioning?_
* Saturates inspired air with water vapour
* Warms up the air
43
What is the defensive function of the pharynx?
* Mucous layer
* Lymphatic vessels + glands
44
Lower respiratory tract
* Trachea, its branching and the lungs
* Function: Filtering and protection
45
Epithelium found in the lower respiratory tract
Pseudostratified ciliated columnar epithelium
Contains goblet cells
46
Goblet cells produce...
Mucine - IgA
47
Cilia of the epithelium are moving in...
Sol phase
48
Terminal bronchiolus
49
* Bronchiolus* *respiratorius*
* Respiratory epithelium appears
50
Give the layers (alveolar) between blood and atmospheric air
1. Surfactant layer
2. Alveolar layer
3. *Membrana* *basalis*
4. Capillary endothel
51
The alveolar wall is built up of which pneumocytes?
* Epithel → Provides gas exchange
* T2 → Produce surfactant layer
52
Muscles involved in inspiration
* Diaphragm
* External intercostal muscles
* Abdominal muscles
53
Function of *mm. intercostales externi*
* Raise ribs, assist inspiration
* Parietal region of the diaphragm can dilate easier
54
The collapsing tendency of the lung is due to...
* The surface tension of alveoli
* Elastic elements of the lung
55
Total collapse of the lung is prevented by...
Fluid-film between:
* Visceral pleura
* Parietal pleura
56
Pause of respiration
The retractive force of lung balanced with the tension of muscles and joints of the chest (rest)
57
Rate of respiration is dependent on...
Metabolic activity
58
Inspiration or expiration?
Inspiration
59
Inspiration or expiration?
Expiration
60
What do the blue lines represent?
Tendon-lamella
61
Collapsing tendency of the lungs reduces...
Lung volume during expiration
62
Title the figure
The mouse-elephant curve
63
Which air-flow types are observed in panting?
* Parietal
* Central
64
What kind of gas exchange occurs during panting?
Physiological gas exchange
* Slight change in gas pressure
65
During panting, parietal gas exchange is...
Slow
66
Central gas stream
* Fast
* Heat exchange
* Stimulates water release in mouth
67
Panting in species other than canines would cause...
* Loss of CO2
* Alkalosis
68
The spirometer measures...
Volume changes and air fractions of breathing
69
Ventilation
* The quantity of air entering and leaving the lung
* Per unit time
70
In the spirometer, the height of the upper cylinder indicates...
The size of the given volume fraction
71
Inspiratory Reserve Volume
| (IRV)
72
Tidal volume
| (TV or VT)
73
Expiratory Reserve Volume
| (ERV)
74
Residual Volume
| (RV)
75
Inspiratory Capacity
| (IC)
76
Functional Residual Capacity
| (FRC)
77
Vital Capacity
| (VC)
78
Total Lung Capacity
| (TLC)
79
VC =
VT + IRV + ERV
80
The deepness of inspiration increases...
* The proportion of fresh air : used air
* Measured with Ventilation coefficient
81
Ventilation coefficient
Vcoeff = fresh/used
82
Volume dead
* Anatomical + physiological dead-space
* Doesn't contribute to gas exchange
83
What contributes to _anatomical_ dead space?
* Air fraction of:
* Upper respiratory tracts
* Lower respiratory tracts
84
What contributes to the _physiological_ dead space?
* Occluded alveoli
* Alveoli excluded from circulation
85
Used air =
FRC + VD
86
Fresh air =
VT - VD
87
Pressure change in the pleural cavity
Intrapleural pressure
88
Pressure change in the lung
Intrapulmonar pressure
89
Intrapleural pressure is always...
Negative
90
Why is the intrapleural pressure always negative?
Gases constantly being absorbed by tissue
91
Formula for transpulmonary pressure
Ptp = Palv - Ppl
92
During apnea, pulmonary pressure is equal to...
Atmospheric pressure
93
Pulmonary pressure
94
Intrapleural pressure
95
Volume
96
Apnea
97
Inspiration
98
Expiration
99
Müller's experiment
* Deep inspiration with a closed epiglottis
* Pulmonary and intrapleural pressure decreases
100
Valsava experiment
* Forced expiration with closed epiglottis
* Pulmonary + Intrapleural pressure increase
## Footnote
*Used to equalise pressure in the ear*
101
Pneumothorax
* Loss of intrapleural negative pressure
* Small: Escaped air can be reabsorbed from the pleural cavity
* Large: Air needs to be drawn out of the pleural cavity
102
Closed pneumothorax
* Small hole in thoracic wall/lung
* Air gradually absorbed, IP pressure returns
103
Open pneumothorax
* Large hole
* IP is atmospheric
104
Valvular/tension pneumothorax
* Flap of tissue acts as a valve over the hole
* Allows air entry during inspiration
* Doesn't allow escape during expiration
* Lung severely collapses
105
Emphysema
* Septa between alveoli are damaged
* Reduced respiratory surface
106
Resistance forces which need to be overcome during inspiration
* Friction
* Non-elastic tissue resistance
* Total elastic resistance
107
Friction force effect on inspiration
* Smallest force of resistance
* Caused be turbulent air flow
108
Non-elastic tissue resistance during respiration
* Caused by:
* Diaphragm
* Chest
* Abdominal structures
109
Total elastic resistance of inspiration
* Stretch of vertebral + costal joints
* Retractive forces
* Resistance of interstitial elastic elements
* Surface tension in the alveoli (Strongest)
110
Surface tension
* Cohesive forces
* Internal pressure
* Causes liquid surfaces to contract to minimal area
111
Forces causing the collapse of alveoli
* Retractive tendency of elastic elements
* Surface tension
112
Forces acting against collapse of alveoli
* Actual intrapulmonary pressure
* Surface tension of neighbouring alveoli
* Presence of surfactant
113
The result of alveolar dilating and retracting forces...
Transpulmonary pressure
114
The open state of alveoli can be maintained only by...
Materials reducing surface tension
115
DPPC
* Reduces surface tension
* If not present:
* Fatal alveolar collapse
* Plasma filtrated into alveoli (Reduced diffusion)
116
DPPC deficiency occurs genetically in...
* Calves
* Causes early postnatal death
117
How does lack of DPPC cause death?
* Intrapleural pressure higher (30mmHg)
* Alveolus cannot stay open against larger wall tension
118
delta V / delta P =
Compliance
119
Compliance
The ability of a hollow organ to change its volume
120
Figure showing compliance in the lungs
121
Surfactant layer during inspiration
* Thicker
* Lower number of DPPC on air-liquid interface
* Only molecules on the surface can display tension-reducing effect
122
As the alveolus expands, DPPC...
* Can act on a larger surface area
* Surface tension gets smaller
123
Smaller changes in pressure may result in...
High unit volume changes
124
DPPC max
* DPPC molecules used up
* Further volume increase requires exponential pressure increase
125
Amount of DPPC on the alveolar surface
126
Changes in volume depend on...
DPPC availability in the alveoli
127
Surfactant is produced by...
Type II alveolar cells
128
Respiratory gas exchange is determined by...
* Partial pressure
* Diffusion conditions
* Surface size
* Metabolic activity (O2 consumption)
129
Dalton's law
* Calculate partial pressure
* P/Ptotal = V / VT
130
Henry-Dalton's law
* Expresses how a gas is diluted in fluid
* C = alpha x P
131
* STPD
* BTPS
* Standard temperature and pressure
* 760mmHg
* 0°C
* Free of water vapour
* Body temperature and pressure
* 760mmHg
* 37°C
* Saturated with water vapour
132
Partial pressure
Measure of how much gas is present
133
Partial pressure of oxygen in the air
160 mmHg
134
DCO2 =
20 x DO2
135
What binds 70x less O2 than the blood?
Plasma
136
Average O2 consumption of animals
300 mlO2/min/100kg
137
O2 consumption rate during forced physical performance
6000 mlO2/min/100kg
138
1 Hb binds ... O2
4
139
Speed of haemoglobin saturation
10 msec
140
Factors affecting haemoglobin O2 affinity
* Body temp
* Partial pressure CO2
* 2,3-DPG concentration
* pH
* CO
* Myoglobin
141
Oxygen saturation curve shape
Sigmoidal
142
Why is O2 saturation curve sigmoidal?
* The binding of the first O2 facilitates the next
* By allosteric stimulation
143
Normal arterial and venous blood saturation %
A: 95%
V: 75%
144
A shift to the right of the O2 saturation curve can be caused by...
* Increase pCO2
* Increased pH
* Increased Temperature
* Increased 2,3-DPG
145
What is shown in the figure?
Change of O2 affinity of hemoglobin by pCO2 change
146
What is shown in the figure?
Change of O2 affinity of hemoglobin by pH change
147
Bohr shift
* Decreased CO2 → pH increase
* Haemoglobin picks up more oxygen
148
What is shown in the figure?
Change of O2 affinity of hemoglobin by temperature change
149
What is shown in the figure?
Change of O2 affinity of hemoglobin by 2,3 DPG change
150
Describe the effect of 2,3-DPG increase
* By-product of 2,3-DPG displaces O2 from Hb
* Saturation curve shifts to the right
* More O2 is given to the tissues
151
Embryonic haemoglobin is less capable of binding...
2,3 DPG
* Affinity is higher than maternal blood
* Embryo can easily get O2 from the mother's blood
152
CO binding is...
Irreversible
153
Change of O2 affinity of hemoglobin by myoglobin change
Non-sigmoidal curve
* Myoglobin takes O2 from Hb, storing it in the muscle
154
The fate of CO2 when it enters the capillary
* Converted to bicarbonate (with carbonic anhydrase)
or
* CO2 present in the blood:
* Physically dissolved
* Protein-bound
All form an equilibrium
155
H+ produced when CO2 enters the blood is bound by...
Deoxihemoglobin
156
Water + CO2
H2O + CO2 → HCO3- + H+
157
If haemoglobin is not deoxygenated by the tissues...
Removal of CO2 is damaged
158
RBC membrane is impermeable to...
K+
159
Describe the function of capnophorine transporter
* Exchanges bicarbonate to chloride
* Ensuring electroneutrality
160
Significant increase in IC Cl- concentration caused by capnophorine leads to...
Hamburger shift
161
Cl- transport into the RBC causes
* Simultaneous intracellular H2O migration
* Causes cell volume increase
162
What provides the buffer-base effect of blood?
* Deprotonated hemoglobin
* Bicarbonate in the plasma
163
Haemoglobin buffer (Tissue)
Deoxyhaemoglobin produced → H+ acceptor
164
Haemoglobin buffer (Lung)
* H+ released from deoxyhaemoglobin
* Oxyhaemoglobin created at lung-level
165
Carbamino haemoglobin (tissue)
* From CO2 binding haemoglobin
* H+ dissociates
166
Carbamino haemaglobin (Lung)
* CO2 released from carbamino haemoglobin
* Deoxyhaemoglobin uptakes H +
167
Title the figure
CO2 dissociation curve
* Shows quantity of CO2 transported in the blood
* As a function of pCO2
168
The haldane effect
* Increased pO2 → Decreased chemically bound CO2
* High oxygen tension stimulates CO2 release
169
CO2 concentration in arterial blood
22.1 mmol/l
170
CO2 concentration in venous blood
24.4 mmol/l
171
What is detected during breathing regulation?
Gas tensions of blood
172
Effect of severing: Above the pons
* [1]
* No effect
173
Effect of severing: Middle of the pons
* [2]
* Deep inspirations
* Inspiration-inhibiting centre cut
174
Effect of severing: Border of pons and medulla oblongata
* [3]
* Deeper + Shallow breathing
* _Apneustic centre_
* Responsible for normal rhythm
175
Effect of severing: Medulla above the exit point of *n. phrenicus*
* [4]
* Respiratory cycle stops
* Autonomous respiratory group cut
* DRG (Dorsal respiratory group)
* VRG (Ventral respiratory group)
176
Effect of severing: below the exit point of *n. phrenicus*
* [5]
* No change is respiration
* Respiration regulating groups located above this point
177
Effect of cutting *n. vagus*
Deep inspiration, sudden expiration
178
Hering-breuer reflex
* Inspiration inhibiting reflex
* Stretch receptors detect stretching
* DRG centres recieve afferentation *via n. vagus*
* Stimulates VRG
179
Which afferent nervous factors other than Hering-Breur influence respiration?
* Emotional changes
* Hyperventialtion
* Pain
* Sleeping
* Baroreceptor-related circulatory/ respiratory reactions
180
Efferent nervous respiratory signals run to the...
Respiratory muscles
181
Efferent stimulation of inspiration
* Stimulation of respiratory muscles
* Expiratory muscles inhibited
* *N. phrenicus* stimulated
182
Efferent stimulation of expiration
* Normally passive
* Inspiratory muscles inhibited
* Expiratory muscles stimulated
183
Which is more important:
* Peripheral reception
* Cenral reception
Central reception
184
Location of the highest sensitivity to
* pCO2 of blood and CSF
* pH
* The bottom of the IVth ventricle
* Influences the DRG (inspiratory)
185
How does CO2 stimulate DRG activity?
* CO2 → CSF
* pH drop → DRG activity stimulated
186
Receptors of peripheral reception are located...
* Glomus caroticum (Carotid body)
* Glomus aorticum (Aortic body)
187
Glomus caroticum
* Cluster of chemoreceptors
* Found at bifurcation of the carotid artery
188
Glomus aorticum
* Chemoreceptors and baroreceptors
* Located along the aortic arch
189
Peripheral reception is sensitive to...
pO2
190
Secondary protective mechanism
* By peripheral reception
* pO2 reception
* Generates hyperventilation
191
Breathing type
Normal
192
Breathing type
Biot
* Long apnea
193
Breathing type
Cheyne-Stokes
* Characteristic periodicity
194
Breathing type
Kussmaul
* Found in uremia and diabetic coma
195
Normal breathing
* Steady inspiration + Expiration
* Uniform depth
196
Dyspnea
Random breathing
197
List the defensive respiratory reflexes
* Sneezing
* Coughing
* Nociceptive apnea
* Diving reflex
* Combined swallowing reflex
198
Sneezing
* Mechanical/chemical irritation of upper respiratory tract
* Speed: 300 m/s
199
Coughing
* Tracheo-bronchial irritation
* Mechanism similar to sneezing
200
Nociceptive apnea
* Prevents inhilation of gases or fumes
* Sudden apnea
* Same may happen for pain or cooling sensation
201
Diving reflex
* Water in contact with the head
* Breathing motions inhibited
* Protection from inspiration of water
202
Combined swallowing reflex
* Foot touches pharyngeal wall
* Apnea → prevents choking
203
Birds ventilate their lungs by expanding...
Their air sacs
204
The cranial group of air sacs contain...
Used air
205
The caudal group of air sacs contain...
Fresh air
206
Mechanism of air sacs
* Inhalation 1: Caudal air sacs fill
* Exhalation 1: Caudal air sacs empty, lungs fill
* Inhalation 2: Cranial air sacs fill
* Exhalation: Cranial air sacs empty
207
Benefit of the avian breathing cycle
* Continuous gas exchange
* Continuous respiration
* Allows higher energy level than mammals
208
The finest branches of the avian bronchial system
Parabronchi
* Allows air to flow through unlike mammalian alveoli
209
Countercurrent flow in the lung
* Allows gas exchange
* Air and the blood flow to eachother
210
The lower gas-exchange capacity of bovines is a predisposing factor for...
Broncho-alveolar hypoxia
211
Broncho-alveolar hypoxia reduces...
Pulmonary clearance rate
212
Relatively higher air-exchange activity increases the risk of...
Pulmonary infectinon
