Structure and function of the airways Flashcards

1
Q

Why does the trachea not have rings of cartilage?

A

There is the oesophagus running down the back of the trachea
So if rings went all the way around- they would impact swallowing food down the oesophagus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the shape of the cartilage in the trachea?

A

C shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the “basic” aspects of the airway?

A

airways, lungs, nasal passages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Go from the trachea down, what are the airways?

A

Trachea, primary bronchus, secondary bronchus (lobar), tertiary bronchus (segmental), bronchioles, alveolus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What provides mechanical stability to the airways?

A

cartilage (holds them open)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what type of branching does the airway have?

A

dichotomous branching

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens at the alveolar region?

A

gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the components of the alveolar region?

A

Alveolar duct, alveoli, alveolar sac, respiratory bronchioles, terminal bronchiole (non-cartilaginous)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where specifically in the alveolar region does gas exchange occur?

A

alveolar unit- capillary endothelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the cells present in the pipework of the alveolar unit?

A

Type I cell, Type II cell, Macrophage, stromal cell (fibroblast)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are type I cells?

A

very thin, delicate barrier (facilitate gas exchange)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are Type II cells?

A

replicate to replace Type I, secrete surfactant and antiproteases
Part of xenobiotic metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the role of surfactant in the lungs?

A

reduces surface tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is xenobiotic metabolism?

A

getting rid of bad stuff that has been inhaled in simple terms

The xenobiotic metabolism in the lung, an organ of first entry of xenobiotics into the organism, is crucial for inhaled compounds entering this organ intentionally (e.g. drugs) and unintentionally (e.g. workplace and environmental compounds).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How much do type I cells cover?

A

over 95% of alveolar surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Are there more Type I or Type II cells?

A

more type II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are 2 basic functions of the respiratory airways?

A

getting air efficiently to the gas exchange region, and keeping the pipework clear.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the conduits (pipes) for?

A

conduct O2 to alveoli, conduct CO2 out of the lungs
- for gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the conduits (pipes) facilitated by?

A

mechanical stability (cartilage)
control of calibre (smooth muscle)
protection and cleansing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the regions of the pharynx?

A

nasopharynx
Oropharynx
Laryngopharynx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the conchae in the nasal passage?

A

high vascularised- contribute to warming and humidification of intra-nasally-inhaled air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What do nasal hairs do?

A

they filter out large particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the pharynx?

A

a common passage for food, liquids, and air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the organisation of airway structures (transverse section)?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the structure of the airway wall?

A

mucus layer–> cilia–> epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the lining cells?

A

ciliated, intermediate, nursh, basal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the contractile cells?

A

smooth muscle (airway, vasculature)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the secretory cells?

A

goblet (epithelium), mucous, serous (glands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the connective tissue cell types?

A

fibroblasts, interstitial cell (elastin, collagen, cartilage)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the neuroendocrine cell types?

A

Nerves, ganglia, neuroendocrine cells, neuroepithelial bodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the vascular cells?

A

endothelial, pericyte, plasma cells (+smooth muscle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the immune cells?

A

Mast cell, dendritic cell, lymphocyte, eosinophil, macrophage, neutrophil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How would you describe epithelial cells?

A

They have cilia

They have lots of mitochondria, because they are highly metabolically active, always wafting

34
Q

What do goblet cells contain?

A

mucin granules

35
Q

What do mucin granules contain?

A

mucin in a highly condensed form

36
Q

What happens during mucin secretion?

A

expansion of intra-granular mucin upon secretion; to ATP

37
Q

What do human bronchial glands have?

A

mucous and serous acini

38
Q

What is the difference between mucous and serous acini?

A

mucous acini= more viscous mucus

serous acini= more watery mucus

39
Q

What do mucous cells secrete?

A

mucus

40
Q

What do serous cells secrete?

A

anti-bacterial enzymes (e.g., lysosomes)

41
Q

What do airway submucosal glands secrete?

A

They also secrete water and salts e.g., Na+ and Cl-

42
Q

How many cilia per ciliated cell?

A

roughly 200

43
Q

What is the structure of a cilia?

A
44
Q

What is the 9+2 referring to?

A

the microtubule arrangement

45
Q

How do cilia beat?

A

in a metachronous beating/ metachronal rhythm

46
Q

Why are there different fields of cilia?

A

They are out of time with each other
So overall mucus will move
Even though cilia go back and forth

47
Q

What are the functions of the epithelium?

A

Secretion of mucins, water and electrolytes
Movement of mucus by cilia- mucociliary clearance
Physical barrier
Production of regulatory and inflammatory mediators

48
Q

What is important about the secretion of mucins, water and electrolytes?

A

they are components of mucus (+plasma, mediators etc.)

49
Q

What are the inflammatory mediators produced by the epithelium?

A

– Nitric oxide (NO - via nitric oxide synthase, NOS)
– Carbon monoxide (CO - via hemeoxygenase, HO)
– Arachidonic acid metabolites (e.g. prostaglandins – via COX)
– Chemokines (e.g. interleukin (IL)-8)
– Cytokines (e.g. GM-CSF)
– Proteases

50
Q

What stains nitric oxide synthase?

A

anti-NOS antibody, brown staining

51
Q

How can you “stain” for smooth muscle?

A

in culture- actin fluorescence

52
Q

What happens to smooth muscle during inflammation?

A

structure: hypertrophy, proliferation

tone: (airway caliber) relaxation or contraction

secretion: mediators, cytokines, chemokines

53
Q

What are the specific secretory functions of smooth muscle during inflammation?

A

bacterial products and cytokines lead to…

NOS and COX (cyclooxygenase)=> nitric oxide and prostaglandins

cytokines, chemokines, adhesion molecules=> inflammatory cell recruitment

54
Q

What is the airway vasculature?

A

Tracheo-bronchial circulation (systemic)

55
Q

What is the tracheo-bronchial circulation part of?

A

systemic- part of the systemic circulation that supplies nutrients and oxygen to the cells that constitute the lungs, as well as carrying waste products away from them

56
Q

How much of the caridac output goes ot tracheo-bronchial circulation?

A

1-5%

57
Q

What is the blood flow to airway mucosa?

A

100-150 mL/min/100g tissue (amongst the highest to any tissue)

58
Q

Where do bronchial arteries arise from?

A

aorta, intercostal arteries and others

59
Q

how does blood return from the tracheal circulation?

A

via systemic veins

60
Q

How does blood return from the bronchial circulation?

A

Blood returns from bronchial circulation to both sides of heart via bronchial and pulmonary veins

61
Q

What makes up the subepithelium microvasculature network of the trachea?

A

artery, capillary, vein

62
Q

What is the function of the tracheo-bronchial circulation? (7)

A
  • Good gas exchange (directly between airway tissues and blood)
  • Contributes to warming of inspired air
  • Contributes to humidification of inspired air
  • Clears inflammatory mediators
  • Clears inhaled drugs (good/ bad, depending on drug)
  • Supplies airway tissue and lumen with inflammatory cells
  • Supplies airway tissue and lumen with proteinaceous plasma (termed ‘plasma exudation’)
63
Q

How is the airway function controlled?

A

Nerves
Regulatory and inflammatory mediators
Proteinases/ proteases e.g., neutrophil elastase
reactive gas species e.g., O2-, NO

64
Q

How do nerves control the airways?

A

parasympathetic= cholinergic
sympathetic= adrenergic
sensory

65
Q

How do regulatory and inflammatory mediators control the airways?

A

Histamines
Arachidonic acid metabolites (e.g., prostaglandins, leukotrienes)
Cytokines
Chemokines

66
Q

What does the innervation of the airway look like?

A
67
Q

What are the regulatory-inflammatory cells in the airway?

A

Eosinophils
Neutrophils
Macrophages
Mast cells
T lymphocyte
+ structural cells (e.g., airway smooth muscle)

68
Q

What do structural cells, like the airway smooth muscle, do in terms of regulatory-inflammatory control?

A

(contraction, relaxation)
Secretion of mucins, water, etc.
Plasma exudation
Neural modulation
Chemotaxis
Remodelling

69
Q

Can cells produce more than one mediator?

A

yes, and the mediators can do more than one thing

70
Q

What are the mediators/ secretions/ whatever from the regulatory-inflammatory cells?

A

Histamine
Serotonin
Adenosine
Prostaglandins
Leukotrienes
Thromboxane
PAF
Endothelin
Cytokines
Chemokines
Growth factors
Proteinases
Reactive gas species

71
Q

What are common respiratory diseases?

A

– Asthma – ~5% of population (industrialised countries)

– COPD – 4th cause of death in UK and USA

– CF – lethal autosomal recessive gene defect (~1:20 gene frequency; affects ~1:2,000 Caucasians)

72
Q

What can cause chronic obstructive pulmonary disease?

A

smoking, cooking over open fire, very bad pollution

73
Q

What are characteristics of respiratory diseases?

A

airway inflammation, airway obstruction, airway remodelling

74
Q

What does dichotomous branching aid?

A

the efficient delivery of air into the alveoli

75
Q

What is an example of homeostatic cleansing mechanism?

A

mucociliary clearance

76
Q

What is the upper airway?

A

nasal passage,s they filter, warm and humidify nasally inhaled air

77
Q

How many cell types are found in the airways?

A

at least 22

78
Q

What can have a possible control over ciliary beating?

A

nitric oxide, cilia beat metachronally

79
Q

Overall, what can the functions of the smooth muscle in the airway be split into?

A

contractile and secretory

80
Q

How does airway relaxation occur?

A

via NOS containing nerves and adrenaline (adrenal glands)

81
Q

What precipitates to lung disease?

A

Loss of homeostatic control