Respiratory 1 Flashcards
1
Q
Which structures ar involved in the conducting zone
A
Trachea
Bronchi
Bronchioles
Terminal bronchioles
2
Q
Which structures ar involved in the respiratory zone
A
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
3
Q
Difference between conducting zone and respiratory zone
A
Conducting zone : only a passage way for air (no gas exchange)
Respiratory zone: gas exchange occurs
4
Q
Types of alveolar cells
A
Type 1 alveolar cells
Type 2 alveolar cells (septal cells)
Alveolar dust cells
5
Q
What are type 1 alveolar cells
A
Simple squamous cells where gas exchange occurs
6
Q
What are type 2 alveolar cells
A
Septal cells that secrete surfactant
7
Q
What are alveolar dust cells ?
A
Macrophages that remove debris
8
Q
True or false
the respiratory membrane is extremely thin
A
True
( < 1/2 μm)
9
Q
Purpose of surfactant
A
Reduces surface tension to keep alveoli open and prevents them from collapsing during exhalation.
10
Q
Don’t know if this is important so just read
A
Next
11
Q
Functions of respiratory system
A
Acid-base balance
Water and heat balance
Phonation
Pulmonary defense
Metabolism
Gas exchange (ventilation)
12
Q
How does the respiratory system help maintain acid-base balance
A
By regulating arterial CO2 level and eventually pH
13
Q
How does the respiratory system help maintain water and heat balance
A
Water loss through saturation of inhaled air
Heat loss through respiratory water evaporation
14
Q
How does the respiratory system help with phonation
A
Production of sounds occur by the movement of air through the vocal cords
15
Q
How does the respiratory system aid in pulmonary defense
A
Filtration of inspired air and removal of particulate matter such as dust, pollen, fungal spores, micro organisms, etc.
16
Q
What is the respiratory system‘s role in metabolism
A
Formation and release of substances such as pulmonary surfactant and repair of alveolar surface in response to injury
17
Q
Read
A
18
Q
What is meant by ventilation
A
Movement of gas into and out of the lungs
19
Q
What is meant by alveolar gas exchange
A
Diffusion of O2 from alveoli to blood
Diffusion of CO2 from blood to alveoli
20
Q
What is meant by blood gas transport
A
Gas is present in the blood either in dissolved form, bound to hemoglobin or as other chemical forms
21
Q
What is meant by cellular gas exchange
A
Diffusion of O2 from blood to cells
Diffusion of CO2 from cells to blood
22
Q
Regulation of ventilation is done by ________________.
A
Central nervous system CNS
23
Q
Appreciate the diaphragm in this picture
A
During inspiration, the diaphragm contracts and moves downward providing more space for the lungs to expand
During expiration, the diaphragm relaxes and moves upward
24
Q
Accessory muscles of inspiration for forceful inhalation
A
Sternocleidomastoid
Scalene
Pectoralis major
25
Principle (main) muscles of inspiration for quiet breathing
External intercostals
Interchondral part of internal intercostals
Diaphragm
26
Muscles of expiration for active breathing (forceful exhalation)
Internal intercostals (except interchondral part)
Abdominals
Quadratus lumborum
27
Pressures involved in breathing are :
Airway pressure (P aw)
Alveolar pressure (PA , P alv )
Intrapleural pressure (P pl)
28
What is the visceral pleura
Delicate serous membrane that covers the surface of each lung and dips into the fissures between the lobes
29
What is the parietal pleura
Outer membrane which is attached to the inner surface of the thoracic cavity. It also separates the pleural cavity from the mediastinum
30
What is pneumothorax
Abnormal collection of air in the pleural space
31
What causes pneumothorax and what is its effect on the lungs
Cause: Results from rupture or puncture of the lung or chest wall
Effect on lung: lung elastic recoil causes collapse of the lung
32
Airflow (Q) in and out of the lungs depends on:
33
What causes air to move in and out of the lungs
Changes in alveolar pressure
34
What happens if alveolar pressure (Palv) is LESS than atmospheric pressure (Patm)
Palv < Patm
Air flows INTO the lungs = INSPIRATION
35
What happens if alveolar pressure (Palv) is MORE than atmospheric pressure (Patm)
Palv > Patm
Air flows out of the lungs = EXPIRATION
36
What happens if alveolar pressure (Palv) is EQUAL TO atmospheric pressure (Patm)
Palv = Patm
No pressure gradient so no air is moving in or out of lungs (no air flow)
37
Explain the pressure change during inspiration
38
Explain the pressure change during expiration
39
What happens to pleural pressure during inspiration
Becomes MORE negative
40
What happens to pleural pressure during expiration
Becomes LESS negative
41
What is the relationship between air flow (Q) and airway resistance (Raw)
Inversely proportional
42
Airway resistance (Raw) is determined by which law
Poiseuille law
43
Relationship between the airway resistance (Raw) and air viscosity ?
Directly proportional
44
Relationship between the airway resistance (Raw) and airway length ?
Directly proportional
45
Relationship between the airway resistance (Raw) and airway radius ?
Inversely proportional (to the 4th power)
46
Factors affecting radius of airways
Long volume
Airway smooth muscle tone
Airway inflammation
Airway mucous secretions
47
How does lung volume affect the radius/resistance of airways (bronchioles and small airway diameter)
48
How does the ANS control the diameter of the bronchioles and affect the radius of airways ?
49
Effect of parasympathetic cholinergic fibers on airway radius
- smooth muscle constriction
- increased mucus secretion
= high airway resistance ( high Raw)
50
Effect of sympathetic adrenergic fibers on airway radius
- smooth muscle relaxation
- inhibition of mucus secretion
= decrease airway resistance (Low Raw)
51
How does the sympathetic adrenergic fibers inhibit mucus secretion
Through action on bronchial B2 adrenergic receptors
52
Asthmatic patient gets inhaler / nebulaizer.
Should it contain cholinergic or anti-cholinergic drugs?
anti-cholinergic drugs
(Because cholinergic increase mucus secretion)
53
Asthmatic patient gets inhaler / nebulaizer.
Should it contain B2 adrengeric receptor agonist or B2 adrenergic receptor antagonist?
B2 adrenergic receptor AGONIST
54
Local irritants can cause an increase in inflammatory mediators like:
55
Effect of inflammatory mediators on airway radius and airway resistance
- Constriction of bronchioles
- obstruction of airways
= INCREASE in airway resistance due to decrease in airway radius
56
Diseases that cause airway narrowing are called
Obstructive pulmonary diseases
57
Obstructive pulmonary diseases
Diseases that cause airway narrowing
58
How does obstructive airway diseases effect airway resistance
Increases airway resistance (Raw) due to narrowing of airways
59
Name some diseases that affect small airways
Asthma
Emphysema
Bronchitis
(Hint: BAE)
60
Name some diseases that effect large airways
Trauma
Infectious diseases
Congenital tracheobronchial abnormalities
Inflammatory diseases
Neoplasm
(Hint: TICIN)
61
What are the three basic components of the elastic properties of the lungs
1. Compliance / distensibility
2. Stiffness
3. Elasticity
62
What is meant by compliance and dispensability of the lung
The ease with which of the lungs can be stretched or inflated
63
What is meant by stiffness
Resistance to stretch or inflation
64
What is meant by elasticity
The ability of a stretched or inflated Lunk to return to its resting volume (functional residual capacity FCR)
65
Difference between compliance and elasticity of
Compliance reflects the ability to change the shape of the structure such as stretching,
whereas elasticity reflects resistance to the change in shape ( the ability to return to the normal state )
66
Lung compliance
The change in lung volume resulting from 1 cm H2O change in the descending pressure of the lung
67
Formula for lung compliance
68
Compliance of a normal human lung is about:
0.2 L/cm H2O
69
Lung compliance decreases in what type of disease + provide example
Restrictive pulmonary disease
Example: fibrosis
70
Lung compliance increases in what type of disease + provide example
Obstructive pulmonary disease with air trapping
Example : emphysema
71
Describe the lung compliance for stiff lung
Low lung compliance
72
Describe the lung compliance for distensible lung
High lung compliance
73
Understand this graph
The higher the compliance = the greater the total lung capacity TLC
The lower the compliance = the lesser the total lung capacity TLC
Fibrosis = restrictive pulmonary disease = low compliance
Emphysema = obstructive pulmonary disease = high compliance
74
Effect of surface tension on alveoli
High surface tension causes alveoli to collapse since fluid molecules are attracted and pulled closer together, closing off the alveoli
75
What is pulmonary surfactant
Phospholipoprotein formed by type 2 alveolar cells
76
What is the main lipid components of surfactant
Dipalmitoylphosphatidylcholine DPPC
77
Purpose of pulmonary surfactant
Reduces the surface tension by adsorbing (NOT ABSORBING) to the air-water interface of alveoli, with protein (hydrophilic heads) in the water and the lipid (hydrophobic tails) facing the air
78
By reducing surface tension, surfactant functions to:
79
What is neonatal respiratory distress syndrome
80
What two complications can occur as a result of immature lungs in premature neonates ?
Pulmonary edema
Atelectasis (collapse of lung)
81
What are mothers who are expected to give birth prematurely given and why?
They are given Glucocorticoid injections (Betamethasone)
To stimulate surfactant formation and improve lung function
82
What is tidal volume (TV or VT)
Volume inspired or expired during quiet breathing
83
What is inspiratory reserved volume IRV
Maximum air inhaled from end of normal tidal inspiration
84
What is expiratory reserved volume ERV
Maximum air exhaled from end of normal tidal expiration
85
What is residual volume RV
Air remaining at end of maximum expiration
86
Can residual volume RV be measured by spirometry
NO
87
How can we measure residual volume
Helium dilution method
Nitrogen washout
Whole body plethysmography
88
What is total lung capacity TLC
Air in the lungs after a maximum inspiration
89
What is vital capacity VC
Air that can be exhaled after maximum inspiration
90
What is inspiratory capacity IC
Maximum air that can be inhaled from the end of normal expiration
91
What is functional residual capacity FRC
Volume of air remaining in the lungs at the end of normal expiration
92
Normal tidal volume TV
0.5 L
93
Normal inspiratory reserved volume IRV
3.0 L
94
Normal expiratory reserved volume ERV
1.3 L
95
Normal residual volume RV
1.2 L
96
Normal inspiratory capacity IC
3.5 L
97
Normal functional residual capacity FRC
2.5 L
98
Normal vital capacity VC
4.8 L
99
Normal total lung capacity TLC
6.0 L
100
What is the IRV
IRV = IC - VT = 2.3 - 0.4 = 1.9 L
101
What is ERV
ERV = TLC - IC - RV = 4 - 2.3 - 0.8 = 0.9 L
102
What is VC (or IVC)
VC = TLC - RV = 4 - 0.8 = 3.2 L
103
What is FRC
FRC = TLC - IC = 4 - 2.3 = 1.7 L
104
What does it mean if all lung volumes and capacities are BELOW normal range ?
Lung have smaller size = Restrictive pulmonary disease (ex: fibrosis)
105
We can assess restrictive pulmonary disease using spirometry that will show values that are all below average ,
But how can we assess obstructive pulmonary disease?
FEV1/FVC ratio
106
How is the FEV1/FVC ratio taken?
The subject takes a deep breath and blows out forcefully into a vitalograph that measures the volume exhaled per second
Normal subject can blow out most of his vital capacity VC ( >75% of VC) in the first second
Patient with obstruction cannot because of narrowing of his airways
107
If the FEV1/FVC ratio is equal or above 0.75 
Normal
108
If the FEV1/FVC ratio is less than 0.75
Obstructive pulmonary disease
109
What is FEV1
Forced expired volume in the first second
110
What is FVC
Forced vital capacity is the total volume of air exhaled in the maneuver
111
Difference in pathophysiology of obstructive and restrictive pulmonary diseases
Obstructive pathophysiology:
Limitation of airflow due to increased airway resistance causing partial or complete obstruction
Restrictive pathophysiology:
Reduce expansion of lungs decreasing all lung volumes
112
Examples of obstructive pulmonary disease
Asthma
Bronchitis
Emphysema
(Hint: BAE)
113
Examples of restrictive pulmonary diseases
Fibrosis
pneumonia
asbestosis
pleural effusion
(Hint: FAPP)
114
Compare total long capacity TLC in both obstructive and restrictive pulmonary diseases
Obstructive: TLC is normal or high
Restrictive: TLC is low ( all lung volumes are low)
115
Compare FEV1/FVC ratio between obstructive and restrictive pulmonary diseases
Obstructive:
FEV1/FVC : LESS than 0.75
Restrictive:
FEV1/FVC : EQUAL or MORE than 0.75
116
Compare lung compliance between obstructive and restrictive pulmonary diseases
Obstructive: high lung compliance
Restrictive: low lung compliance
117
What is physiologic dead space VD (wasted ventilation)
The volume of air that enters the lungs but does not participate in gas exchange
118
Two types of dead space
Anatomic dead space
Alveolar dead space
119
What is anatomic dead space
The volume of air in the conducting airways including the nose/mouth, pharynx, trachea, bronchi and bronchioles which does not participate in gas exchange
120
What is alveolar dead space
The volume of air in the alveoli that are ventilated but not perfused
121
How to calculate physiologic dead space
Anatomic dead space + alveolar dead space
122
What is minute ventilation VE
Volume of air entering or leaving the nose/mouth per minute
123
How to calculate minute ventilation
Tidal volume TV ( ml) x respiratory rate (breaths per minute)
VE = TV x RR
124
Unit of minute ventilation
Ml/min
125
What is alveolar ventilation VA
The volume of air that reaches the alveoli per minute and contributes to gas exchange (Excluding dead space volume VD)
126
How to calculate alveolar ventilation
VA = (Tidal volume - dead space) x respiratory rate
VA = (TV-VD) x RR
Unit: ml/min
