Respiratory Physiology Flashcards
1
Q
The conducting zone transports gas to the lungs and is from the nose to the:
A
Terminal bronchioles
2
Q
The respiratory zone is the site of gas exchange and consists of:
A
respiratory bronchioles, alveolar ducts, alveolar sacs
3
Q
How many generation of airways do you find int he respiratory system?
A
23
4
Q
How many alveoli are present in the respiratory system?
A
500 million
5
Q
What is the sympathetic and parasympathetic effect on the smooth muscles of the airways?
A
Sympathetic: smooth muscle relaxation via B2 receptors
Parasympathetic: smooth muscle contraction via muscaric receptors
6
Q
Type of pneumocyte which composes 96-98% of surface area, and is for gas exchange
A
Type I pneumocytes
7
Q
Type of pneumocyte which composes 2-4% of surface area, and is for surfactant production
A
Type II pneumocytes
8
Q
Alveolar macrophages can convert into what in CHF:
A
Siderophages/ Hemosiderin-laden macrophages
9
Q
Cells that produce mucus:
A
Goblet cells, submucosal glands
10
Q
May play a role in epithelial regeneration after injury by secreting protective GAGs
A
Clara cells/Club cells
11
Q
What is the Reid’s index?
A
Ratio of submucosal gland layer to the alveolar wall.
In COPD, Reid’s index is >0.4 indicating hyperplasia and hypertrophy of the submucosal gland layer
12
Q
Dual blood supply of the lungs:
A
- Pulmonary (deoxygenated blood) circulation
- Bronchial (oxygenated blood) circulation (1/3 returns to R atrium via bronchial veins, 2/3 returns to L atrium via pulmonary veins)
13
Q
Amount of air inspired/expired during quiet breathing
A
Tidal volume
14
Q
Maintains oxygenation between breaths
A
Residual volume
15
Q
Sum of IRV, TV, ERV
A
Vital capacity
16
Q
Sum of ERV and RV
A
Functional residual capacity
17
Q
Sum of IRV and TV
A
Inspiratory capacity
18
Q
Sum of all 4 lung volumes
A
Total lung capacity (Normal: 6L)
19
Q
Cannot be measured directly by spirometry
A
Residual volume (and all lung capacities that include residual volume)
20
Q
Equilibrium/resting volume of the lung
A
Functional residual capacity
21
Q
Marker for lung function
A
Functional residual capacity
22
Q
Difference in lung volumes/capacities among sexes
A
Lung volumes and capacities 20-25% lower in females
23
Q
Factors that increase vital capacity
A
Body size, male sex, conditioning, youth
24
Q
Total volume of the lungs that does not participate in gas exchange; anatomic dead space + alveolar dead space
A
Physiologic dead space
25
Air in the conducting zone is called the anatomic dead space. What is the normal value in healthy humans?
150mL
26
Air in the alveoli not participating in gas exchange due to V/Q mismatch.
Alveolar dead space (Normal value in healthy humans is 0 mL)
27
Total rate of air movement in/out of the lungs
Minute ventilation
| MV = VT x RR
28
Minute ventilation corrected for physiologic dead space
Alveolar ventilation
| VA = (VT-VD) x RR
29
25/M, healthy, 70kg with a RR of 20bpm. What is the minute ventilation and alveolar ventilation?
```
MV = 500mL x 20 = 10, 000mL or 10L
VA = (500mL - 150mL) x 20 = 7,000mL or 7L
```
30
```
50/M with TV = 500mL, RR = 20bpm, PCO2 arterial = 40mmHg, PCO2 expired air = 30mmHg.
What is the minute ventilation?
What is the alveolar ventilation?
What percent of TV reaches the alveoli?
What percent of TV is dead space?
```
MV = 500mL x 20 = 10,000 mL or 10L
Physiologic dead space = (0.5L) x (40mmHg - 30mmHg)/40mmHg = 0.125L
VA = (0.5L - 0.125L) x 20 = 7.5L
Percent reaching the alveoli: (0.5 - 0.125)/0.5 = 0.75 = 75%
Dead space: 0.125/0.5 = 0.25 = 25%
31
What happens to FEV1 and FVC in patients with obstructive and restrictive lung diseases?
Decrease
32
What is the FEV1/FVC ratio of a healthy person?
0.8 / 80%
33
What happens to the FEV1/FVC ratio in patients with obstructive and restrictive lung diseases respectively?
Obstructive: Decrease
Restrictive: Normal to increase
34
Normal inspiration is an active process carried out by what muscle?
Diaphragm
35
Predominant muscle in forced expiration
External intercostals
36
Normal expiration is a passive process. However, forced expiration is predominantly done by what muscle:
Internal intercostals
37
In obstructive lung disease, the decrease in FEV1 is ___ than decrease in FVC
greater
38
In restrictive lung disease, the decrease in FEV1 is ___ than decrease in FVC
less
39
```
In emphysema:
Pathology is: loss of _____ fiber
Compliance: ___________
Elasticity: ___________
FRC: ___________
Effects: ______-shaped chest
```
```
elastic
increased
decreased
increased
barrel
```
40
```
In fibrosis:
Pathology is: ______ of lung tissue
Compliance: ___________
Elasticity: ___________
FRC: ___________
```
stiffening
decreased
increased
decreased
41
Force cause by water molecules at the air-liquid interface that tends to minimize surface area
Surface tension
42
2 reasons why preterm babies have large collapsing pressure and are prone to atelectasis:
Alveolar radius is 50 micrometers (adult = 100 micrometers)
| Lack mature surfactant
43
Cells that produce surfactant
Type II pneumocytes
44
Main component of surfactant
Water
45
Active component of surfactant
Dipalmitoyl-phosphatidylcholine (DPPC)
46
Mechanism for DPPC reducing surface tension
Amphipathic nature
47
Effects of surfactant on lung compliance
Increase
48
Start of surfactant production
24th week AOG
49
Maturation of surfactant
35th week AOG
50
Test for surfactant
Amniotic L:S ratio
51
Treatment for newborn RDS
Steroids, surfactant
52
Ability of the respiratory membrane to exchange gas between the alveoli and the pulmonary blood
Diffusing capacity
53
Diffusing capacity for O2:
At rest: _____
Maximal exercise: _____
At rest: 21 mL/min/mmHg
| Maximal exercise: 65 mL/min/mmHg
54
Diffusing capacity for CO2:
At rest: _____
Maximal exercise: _____
At rest: 400 - 450 mL/min/mmHg
| Maximal exercise: 1200 - 1300 mL/min/mmHg
55
What are the forms of gases in solutions?
Dissolved gas, bound gas, chemically modified gas
56
What is the only form of gas that contributes to partial pressure?
Dissolved gas
57
What is the only gas in inspired air found exclusively as dissolved gas?
Nitrogen
58
Difference between PAO2 (alveolar PO2) and PaO2 (arterial PO2)
A-a gradient (Normal: not zero; PAO2 > PaO2)
59
Nitrogen, oxygen and CO2 under normal condition exhibit what kind of gas exchange?
Perfusion -limited gas exchange (gas equilibriates with the pulmonary capillary near the start of the pulmonary capillary)
60
CO2 and O2 during strenuous exercise and disease states (emphysema, fibrosis) exhibit what kind of gas exchange?
Diffusion-limited gas exchange (gas doe not equilibriate even until the end of the pulmonary capillary)
61
O2 transport in high altitude is fast or slow?
Slow
62
Equilibration of O2 at sea level is ___ length of the pulmonary capillary
1/3 length
63
Equlibration of O2 at high altitude is ___ length of the pulmonary capillary
2/3 length
64
Percentage of dissolved O2
2%
65
Percentage of O2 bound to Hgb
98%
66
Hgb with attached O2
Oxyhemoglobin
67
Hgb without attached O2
Deoxyhemoglobin
68
Hgb with Fe3+ and doesn't bind O2
Methemoglobin
69
A2Y2, higher affinity for O2
Fetal hemoglobin
70
A2B2, sickled RBCs, less affinity for O2
Hemoglobin S
71
Max O2 binding with Hgb
O2 binding capacity
72
Percent of blood that gives up it O2 as it passes through the tissues
Utilization coefficient
73
O2-Hgb dissociation curve is sigmoidal in shape. What is the PO2 at the following percent saturation:
50% saturated, 75% saturated, 100% saturated
```
50% = 25 mmHg (p50)
75% = 40 mmHg
100% = 100 mmHg
```
74
Binding of first O2 molecule increases affinity for second O2 molecule and so forth
Positive cooperativity
75
Shift to the right or shift to the left?
| Increased P50
Right
76
Shift to the right or shift to the left?
| Increased unloading of O2 to Hgb
Right
77
Shift to the right or shift to the left?
| Increased CO2
Right
78
Shift to the right or shift to the left?
| Increased 2,3 BPG
Right
79
Shift to the right or shift to the left?
| Increased temperature, exercise
Right
80
Shift to the right or shift to the left?
| Acidosis
Right
81
Shift to the right or shift to the left?
| Increased binding of O2 to Hgb
Left
82
Shift to the right or shift to the left?
| Decreased p50
Left
83
Shift to the right or shift to the left?
| Increased Carbon monoxide, HbF
Left
84
90% of chloride in the blood
HCO3-
85
5% of CO2 in the blood
Dissolved CO2
86
3% of CO2 in the blood
Carbamino Hgb
87
Cl-HCO3 exchange in the RBC
Chloride shift (using Band 3 protein)
88
O2 affecting affinity of CO2/H+ to Hgb
Haldane effect
89
CO2/H+ affecting affinity of O2 to Hgb
Bohr effect
90
Haldane effect happens in the:
Lungs
91
Bohr effect happens in the:
Tissues
92
Pressure in the pulmonary circulation is ___ than systemic circulation
less
93
Resistance in the pulmonary circulation is ___ than systemic circulation
less
94
Cardiac output in the pulmonary circulation is ___ than the systemic circulation
equal to
95
Pulmonary blood flow in a supine position is lowest at the apex and highest at the base or same through the entire lung?
same through the entire lung
96
Pulmonary blood flow in a standing position is lowest at the apex and highest at the base or same through the entire lung?
Lowest at the apex and highest at the base
97
Effect of hypoxia (low PAO2) on pulmonary arterioles
vasoconstriction
98
Causes of pulmonary global hypoxic vasoconstriction
high altitude, fetal circulation
99
Called the slow reactive substances of anaphylaxis and causes bronchoconstriction in asthma
Leukotriene C4, D4 and E4
100
Lung zone:
| Local alveolar capillary pressure
Zone 1
101
Lung zone:
Local alveolar capillary systolic pressure > alveolar air pressure during systole but less than that during diastole;
Intermittent blood flow
Zone 2
102
Lung zone:
Local alveolar capillary pressure > alveolar air pressure throughout the cycle;
Continuous blood flow
Zone 3
103
What lung zones do we see in the apex of the lungs at rest?
Zone 2 and 3
104
What lung zones do we see in the base of the lungs at rest?
Zone 3
105
What lung zones do we see in a supine position, or during exercise throughout the lungs?
Zone 3
106
What lung zones do we see in cases of pulmonary hemorrhage or positive pressure ventilation?
Zone 1
107
Site of highest ventilation
Base of the lungs
108
Site of highest perfusion
Base of the lungs
109
Site of highest V/Q ratio
Apex of lungs
110
Ventilated area of the lungs with no perfusion (V/Q = infinity)
Dead space (eg. pulmonary embolism)
111
Perfusion of lungs with no ventilation (V/Q = zero)
Shunt
112
Alveolar gas has same composition as humidified inspired air (PAO2 = 150 mmHg and PACO2 = 0)
Dead space
113
Pulmonary capillary blood has same composition as mixed venous blood: PaO2 = 40mmHg and PaCO2 = 46mmHg
Shunt
114
Creates the basic respiratory rhythm; contains the dorsal respiratory group, ventral respiratory group, central chemoreceptors
Medulla
115
Modifies the basic respiratory rhythm; contains the apneustic and pneumotaxic centers
Pons
116
Inspiratory center; control basic rhythm; for normal respiration
Dorsal respiratory group
117
Overdrive mechanism during exercise; for forced inspiration and expiration
Ventral respiratory group
118
Found in the lower pons; for prolonged duration of inspiration --> decreases RR
Apneustic center
119
Found in the upper pons; shorten duration of inspiration --> increases RR
Pneumotaxic center
120
Found in the ventral medulla, respond directly to CSF H+ (increases RR)
Central chemoreceptors
121
Responds mainly to PaO2
Peripheral chemoreceptors
122
Stimulated by lung distention
Lung stretch receptors
123
Decreases RR by prolonging expiratory time; prevent overinflation of the lungs
Hering-Breuer reflex
124
Stimulated by limb movement; causes anticipatory increase in RR during exercise
Joint and muscle receptors
125
Stimulated by noxious chemicals; causes bronchoconstriction and increases RR
Irritant receptors
126
Found in juxtacapillary areas; stimulated by pulmonary capillary engorgement; causes rapid shallow breathing and responsible for the feeling of dyspnea
J receptors
