Respiratory strand: Lecture 5 - Physiology of the Airway Flashcards
Explain the anatomy of the upper airway (image)
slide 2 image
What happens when the pressure in our airway drops?
- airway has pressure receptors that detect when the pressure drops
- sends efferent message to the vagus nerve
- causes pharyngeal muscles to contract harder
- this is rapid and critical
Name two sleeping disorders and their prevalence?
- snoring (25%)
- sleep apnoea (10%)
What are the clinical features of apnoea?
- snoring
- daytime somnolence
- associated with: obesity and hypertension
How do you treat sleep apnoea?
- weight loss
- CPAP (continuous positive airway pressure: keeps air at higher pressure than atmospheric)
Where do you find cilia epithelial cells & goblet cells?
Nose Pharynx Trachea Bronchi Bronchioles
What is the function of cilia epithelial cells & goblet cells?
to produce airway lining fluid
Why are mucin granules released?
To protect the lungs in response to:
- airway irritation
- tobacco smoke
- infection
What is periciliary layer?
water with salt
What is cilia inhibited by?
- tobacco smoke
- inhaled anaesthetics
- air pollution
- infections
What are the two functions of airway lining fluid?
- Humidification
2. Airway defence
Why do we humidify air?
When we breath in, its not moist or as warm as we’d want
Why is it better breathing through the nose than mouth?
- theres less turbulence and it has to travel less distance
- more air comes into contact with mucus so its better humidified
What is the heat and moisture exchanger?
- part of the humidification of the air
- when dry air passes the fluid water evaporates into the gas mixture
What mechanisms do we have in place to defend our airway?
- most particles we breath n stick to the mucus an we remove it e.g by coughing
- muco-ciliary escalator (mucus transport)
What is expectoration?
Coughing
Give 5 clinical features of cystic fibrosis?
- autosomal recessive inheritance
- abnormal cystic fibrosis transmembrane regulator protein (cftr)
- progressive lung infection and destruction
- affects all systems with epithelial surfaces
What does the cftr protein do?
Protein on epithelial cells that control the airway lining fluid
What are the two layers of airway lining fluid?
Periciliary and mucous
Where are very large particles deposited? What is their mechanism of action? Give two examples
deposited - nose & pharynx
mechanism - intertial impaction
examples - pollen, sawdust
Where are large particles deposited? What is their mechanism of action? Give an examples
deposited - large airway
mechanism - inertial impaction
examples - fungal spores
Where are small particles deposited? What is their mechanism of action? Give two examples
deposited - bronchioles
mechanism - sedimentation
examples - particulate pollution, asbestos
Where are very small particles deposited? What is their mechanism of action? Give two examples
deposited - exhaled
mechanism - diffusion
examples - smoke (including cigarette)
Why are pollution particles so dangerous?
pollution particles can get as far as the bronchioles in the lung where the defence mechanisms are not as strong as its nearer the alveoli
