Lecture 5 - Physiology of the airway Flashcards Preview

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Flashcards in Lecture 5 - Physiology of the airway Deck (33)
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1

What nerve is afferent in pharyngeal dilator refleves

Trigeminal nerve - 5th cranial nerve

2

Efferent nerve in pharyngeal dilator reflexes

vagus nerve - 10th cranial nerve

3

What occurs during pharyngeal dilation in the upper airway

pressure receptors in the brain stem respond to afferent fibres and cause efferent fibres to cause pharyngeal muscle contraction

4

Sleep disordered breathing causes

snoring - 25%
sleep apnoea - 10% (pauses in breathing during sleep due to an obstruction)

5

Clinical features of sleep disordered breathing

snoring sleep
daytime somnolence ( sleepiness)

6

What is sleep disordered breathing associated with

obesity and hypertension

7

Treatment for sleep disordered breathing

weight loss
CPAP (continuous positive airway pressure) - sleep apnoea
used during sleep to avoid obstruction

8

What keeps the airway open

continuous muscle activity
reflex control of the muscles

9

When is control of the muscles poor

during sleep or with sedative drugs

10

Airway lining the fluid histology

Ciliated epithelial cells and goblet cells

11

Nose and pharynx has

pesudostratified cells

12

Trachea and bronchi have

columnar cells

13

Bronchioles have

cuboidal cells

14

What is airway lining fluid produced by?

ciliated epithelial cell and goblet cells

15

What do the ciliated epithelial and goblet cells produce?

mucin granules

16

when is mucin produced

in response to airway irritation
tobacco smoke
infection

17

Lining of the airways

columnar cells, periciliar layer (salt and water) and mucous layer

18

what does the periciliar layer do

removes particles we dont want captured by the mucus up the airway away from the lungs

19

What motion does the cilia use to move the mucus?

periciliar layer allows them to move it.

20

What effects the strokes of the cilia

tobacco smoke
inhaled anaesthetics
air pollution
infections

21

what function does the airway lining fluid perform

humidification
- nose breathing better than mouth breathing
- affected by breathing pattern (at rest and at exercise)
- heat and moisture exchanger
active control of pericilary layer to move mucus .
low humidity - less mucus
high humidity - more mucus

22

how does lining help in airway defence?

Muco-ciliary escalator
mucus and cilia moving things out
expectoration - coughing

23

What is cystic fibrosis

Autosomal recessive inheritance
1 in 2500 births
Abnormal cystic fibrosis transmembrane regulator protein (sodium chloride channel)
Progressive lung infection and destruction
affects all systems with epithelial surfaces (GI, Genital, urinary)

24

What happens when very large particles are inhaled

Deposited in the nose and pharynx. has an inertial impact (resistance of any physical object)
examples pollen and sawdust

25

What happens to large particles

deposited in the large airways
inertial impaction
fungal spores

26

What happens to small particles in the airway

deposited in the bronchioles
through sedimentation
particulate pollution, stone dust, asbestos

27

what happens to very small particles in the airway

it is exhaled through diffusion
eg. smoke

28

What affects the fate of inhaled particles apart from size

humidity in the inspired gas

29

how do inhaler particle size relate to drug delivery system? in the future

size related to site of action in the airway
Large - hay fever
medium - ashtma, COPD
small - absorption in the blood

30

What are non-immunological defences

2. physical barrier and removal
2. chemical inactivation
-lysosome
protease enzyme eg. elastase and anti-protease
-antimicrobial peptides eg. human B defensins
3. Alveolar macrophages (ingest them)