Obstructive Lung Disorders Flashcards

(71 cards)

1
Q

What are the three features of obstructive lung disorders

A
  • Narrowing of an airway so increased resistance to airflow
  • Reduced inflow of gas
  • Reduced inflation of the alveoli
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2
Q

What are two common obstructive lung disorders

A
  • Asthma

- COPD (chronic bronchitis and emphysema)

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3
Q

Other than COPD and asthma, name two other obstructive lung disorders

A
  • Bronchiectasis

- Cystic Fibrosis

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4
Q

What are the five factors affecting airway internal diameter

A
  • Increased mucus production
  • Anatomical features
  • Surrounding pressures
  • Autonomic and NANC systems
  • Inflammation
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5
Q

Which types of cells produce most mucus

A

Goblet cells

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6
Q

What are the two layers of mucus

A

The gel layer (on top) and the sol layer (nearest the cilia)

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7
Q

Which layer of mucus is thicker - the gel layer or the sol layer

A

The gel layer

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8
Q

Which layer of mucus tends to dry out with the movement of gas

A

The gel layer

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9
Q

Which layer of mucus is the cilia covering

A

The sol layer

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10
Q

What is the role of mucus

A

A small volume of mucus is produced continuously. It traps particles and contains antioxidants and antibacterial agents.

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11
Q

Where are goblet cells located

A

In the epithelial layer of small airways

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12
Q

Other than goblet cells, where else is mucus produced

A

Submucosal glands

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13
Q

Where are submucosal glands located

A

Submucosal glands are located deep in the bronchial walls.

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14
Q

Which layer of mucus is more viscous

A

The gel layer of mucus is more viscous than the sol layer. The sol layer is less viscous, allowing the cilia to move.

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15
Q

Which layer of mucus is efficient at trapping particles

A

The gel layer which is superficial.

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16
Q

Which types of membranes produce mucus

A

Mucosal membranes.

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17
Q

Why is mucus slimy and how do molecules within mucus slide over one another

A

This is due to glycoproteins. Chains of glycoproteins trap water between them and allow the molecules to slide over one another.

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18
Q

What are cilia

A

These are projections of airway epithelial cells.

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19
Q

What is the role of cilia in the airways

A

Cilia beat mucus upwards towards the larynx.

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20
Q

What increases the activity of cilia

A

Inhaled chemicals

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21
Q

How can cilia be destroyed

A

Cilia can be destroyed by chemicals and infections.

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22
Q

What causes mucus secretion to be increased

A
  • Neural (vagal) activity
  • Inhaled chemicals such as cigarette smoke
  • Infections and some diseases.
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23
Q

What impact does the production of mucus have on the airways

A

It narrows the airways.

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24
Q

What can be a result of narrowed airways due to mucus production

A

V/Q mismatch due to less oxygen reaching the alveoli and blood leaving this part of the lung being deoxygenated.

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25
Why are smaller airways more likely to collapse compared to larger airways
Because they are not surrounded by cartilage rings. The larger airways contain cartilage and so are relatively rigid.
26
In COPD what are the three factors which cause airflow limitation
- Mucus hypersecretion and obstruction of the lumen - Disrupted alveolar attachments due to emphysema - Mucosal inflammation and fibrosis.
27
What keeps the airways open upon inspiration
The negative pressure surround the airways and the alveoli keeps them open during inspiration.
28
Where is the pressure more negative on inspiration
The alveoli. There is a gradient of pressure as you move from the mouth down to the alveoli.
29
How is the positive pressure on expiration calculated
The total positive pressure is the pressure from the elastic recoil plus the pressure exerted by the contraction of muscles on forced expiration.
30
What is the equal pressure point
The equal pressure point is the point at which the pressure inside the airways equals the pressure outside the airways (the intrapleural pressure)
31
What is more likely in the areas above the equal pressure point
This is where collapse of the airways is more likely as the intrapleural pressure is greater than the pressure within the airways.
32
What happens to the equal pressure point upon exhalation
The equal pressure point moves downwards towards the smaller airways and alveoli which are more susceptible to collapse due to the absence of cartilage.
33
What is the effect of reduced elastic recoil on the equal pressure point
This causes the equal pressure point to move downwards closer towards the small airways and alveoli and therefore increases the risk of airway collapse.
34
Which parasympathetic nerve innervated bronchoconstriction
The vagus nerve
35
Which neurotransmitter is released from the vagus nerve
Acetyl choline
36
Which receptors does acetyl choline innervate when released from the vagus nerve in order to bring about bronchoconstriction
M3 muscarinic receptors on airway smooth muscle.
37
What acts on beta 2 adrenergic receptors in the lungs to bring about bronchodilation
Adrenaline
38
What does NANC stand for
Non-adrenergic, non-cholinergic
39
What happens to the NANC system in asthma and COPD
It is disrupted. This has less immediate and more longer term effects.
40
What are the bronchodilators of the NANC system
Nitric Oxide and VIP
41
What are the Broncho-constrictors of the NANC system
Substance P and neurokinins.
42
What are the inflammatory cells involved in asthma
Eosinophils CD4+ T Helper Cells Macrophages Mast cells
43
What inflammatory mediators are involved in asthma
- Leukotrienes - Interleukins - IgE antibodies - Histamine - Prostaglandins.
44
What is the inflammatory process of asthma
An allergen is detected by IgE antibodies which then bind to mast cells and promote the release of histamine, leukotrienes and prostaglandins. These inflammatory mediators bring about bronchoconstriction. Macrophages also engulf the allergen and present it to CD4+ T cells which release leukotrienes, activating eosinophils. Eosinophils bring about mucus production.
45
What are the main factors affecting airway internal diameter in asthma
- Increased mucus production - Inflammation - Possibly the autonomic and NANC systems
46
What are the main factors affecting airway internal diameter in COPD
- Increased mucus production - Anatomical features - Surrounding pressures - Inflammation
47
What affects airway internal diameter in COPD that is not relevant in asthma
- Anatomical features | - Surrounding pressures
48
What is the difference in reversibility in asthma compared to COPD
Asthma is reversible while COPD is not
49
How do you work out the volume of airflow in relation to the resisatnce
(Upstream pressure - downstream pressure)/Resistance.
50
Which factor greatly increases the resistance to airflow
Radius as resistance is inversely proportional to the radius to the power of 4.
51
What happens to resistance if there is a small decrease in radius
If there is a small decrease in radius there will be a large increase in resistance.
52
What happens to the peak expiratory flow in people with untreated asthma
There are morning dips in the peak expiratory flow.
53
What is airflow
The volume of gas per unit time.
54
What is FEV1
The forced expiratory volume in one second
55
What is FVC
The forced vital capacity - how much they can exhale altogether.
56
What happens to the FEV1 in obstructive disorders
FEV1 is reduced in obstructive lung disorders
57
Why is vital capacity sometimes a better measurement to take than forced vital capacity in people with COPD
Because forced expiration is fast and caused high pressures surrounding the airways that can lead to airway collapse and air trapping. Taking the measurement in a non-forced manner can prevent airway collapse and give a more reliable reading.
58
What is the FEV1/FVC ratio in COPD compared to normal
FEV1/FVC is normally about 70-80% of normal in someone with COPD.
59
What is included in lung volume measurements
All the gas in the respiratory system from the mouth down to and including the alveoli.
60
What is the name of the procedure used to measure lung volumes
Spirometry
61
Which lung divisions need to be added together to give the total lung capacity
The vital capacity plus the residual volume.
62
What is the inspiratory reserve volume
The difference between the tidal volume on inhalation and the maximum inspiratory volume
63
What is the expiratory reserve volume
The difference between the tidal volume on exhalation and the maximum exhaled volume.
64
What is the functional residual capacity
The volume of gas left in the lungs after a normal breath not a forced breath.
65
What two lung divisions need to be added together in order to get the functional residual capacity
The expiratory reserve volume and the residual volume.
66
What happens to the total lung capacity in most COPD patients
This remains within the normal range.
67
What happens to the residual volume in COPD patients
Residual volume increases above the normal range.
68
What happens to the total lung capacity in severe COPD
In severe COPD, TLC increases as the alveolar space increases due to the breakdown of alveolar walls. this causes the total volume of gas in the chest to increase.
69
Give a summary to the changes in lung volume divisions in COPD patients
- FEV1 decreases - FEV1/FVC is around 70% of normal - TLC remains normal unless COPD is very severe, then it increases - RV increases.
70
What happens to the vital capacity in COPD
In mild COPD the vital capacity does not change much. In severe COPD, vital capacity decreases.
71
How do you test reversibility of a lung condition
Test the FEV1 and FVC. Then give a short acting bronchodilator (beta 2 agonist - salbutamol) and wait before measuring these values a second time. In asthma, the values will return to normal. In COPD they will not.