Respiratory Basics Flashcards
What are the factors of normal respiration ?
Inspiration
Expiration
Gaseous exchange
What is the process of inspiration?
Contraction of inspiratory muscles
Enlargement of thorax
Decrease in pressure in relation to atmosphere
Air flows into the lungs
What is the process of expiration?
Mostly passive, but driven by lung recoil
Expiratory muscles used during forced expiration
Where does gaseous exchange take place ?
Across the alveolar-capillary membrane
Explain the process of gaseous exchange.
It the process by which oxygen alveoli in lungs is delivered to the bloodstream.
It is also the elimination of carbon dioxide from blood to alveoli.
What is atmospheric pressure ?
Pressure outside the body
What is Alveolar pressure?
Pressure inside the lungs
What is intrapleural pressure?
Pressure in the pleural space
What are the main factors determining resistance to airflow?
- Type of flow
- Viscosity of gas
- Dimension of airways
What is lung compliance ?
It is a measure of lungs ability to stretch and expand when there is change in volume / change in pressure
What are the 2 different measurements of lung compliance ?
Static compliance & Dynamic compliance
When is static compliance measured ?
When no air is moving.
It is measured at the end of inspiration before expiration
When is dynamic compliance measured ?
During breathing
What does low compliance indicate ?
Stiff Lung
What is ventilation ?
The movement of gas in and out of the lung
What is alveolar ventilation?
Gas that reaches alveoli and is part of gaseous exchange
What is dead space ?
Gas that moves in and out of lung but is not part of gaseous exchange
What is the formula for minute ventilation?
Tidal volume X respiratory volume
What is perfusion ?
Low Pressure System
What is perfusion affected by?
Gravity - creates a gradient from top down
What is V/Q matching ?
It is a ratio used to assess the efficiency and adequacy of matching ventilation and perfusion.
What is the ideal ratio of V/Q matching ?
1
What would a lower ratio indicate ?
There is poor ventilation but adequate perfusion
What would a higher ratio indicate ?
There is adequate ventilation but poor perfusion
What does shunting indicate ?
Hypoxic vasoconstriction
What are the different defences ?
Upper respiratory tract
Mucociliary escalator
Cough
How does the upper respiratory tract act as a defence ?
Filters large particles.
Provide humidification and heats incoming air.
How does the mucociliary escalator act as a defence ?
Respiratory tract is lined with epithelial cells.
Contain cilia in a fluid layer
Thicker gel layer on top
Cilia beat rhythmically propelling the secretions to the top of the respiratory tract
When would the mucociliary defence be impaired ?
If there are any changes in consistency of secretions
Or
Cilia is paralysed
What is the function of the cough ?
To clear blockages and excess secretions
What are the phases of a cough?
Deep inspiration
Closure of glottis
Build up of pressure - active expiration against closed glottis
Sudden opening of glottis - air explodes outwards - shearing of secretions off walls of airways
