L05: Pressure And Compliance Flashcards
What does compliance want the lungs to do
Expand
What does elasticity want the lungs to do
Recoil
What does surface tension want the lungs to do
Collapse
How many litres is the total lung compliance
6L
What is total lung capacity made of
Residual volume
Vital capacity
What is the residual volume
Volume of air left after a forced expiration
What is vital capacity
Volume of air that is pushed out after a forced expiration
What is the average residual volume in litres
1.2L
What is the average vital capacity in litres
4.8L
What is the functional residual capacity
Total volume of air in the lungs after a normal exhalation
What is the FRC after a normal breath
2.7L
What is the tidal volume
Volume of breathed in after a normal breath
In litres what is the average tidal volume
0.5L
How can the volume of air inspired and expired vary
Age Sex Height Race Respiratory disease
What does the boyles law state
If the volume increases, the pressure decreases
What does PA represent
Alveoli pressure
What does PB represent
Atmospheric barometric pressure
Between atmospheric/barometric pressure and alveoli pressure what has to be present for air to flow in and out of the lungs
Pressure difference
How do we change PA (alveoli pressure) using the boyles law
Change the volume
How do we change the volume to change the pressure
Via muscles
Which muscles are used in inspiration
Diaphragm
External intercostal
Sternocleoidomastoid
Scalenes
Which muscles are used in expiration
Internal intercostal
Abdominal muscles
How is the lung and the thoracic cage stuck together
By pleural fluid
Inside the pleural fluid what type of pressure is there
Negative intrapleural pressure
How is the negative intrapleural pressure formed
The lungs tendency to recoil inwards
Thoracic cage tendency to recoil outwards
What is the total system compliance
The lung and the chest wall are connected and so they are stretched together
What happens to the total system compliance when distending pressure is 0
The total system compliance is at FRC
What does it mean to have the total system compliance at FRC when distending pressure is 0
Lung and thoracic distending pressure is equal and opposite at FRC
What is a pneumothorax
A collapsed lung
Why does pneumothorax occur
When air leaks into the pleural space and distending pressure is lost
What are the types of pneumothorax
Primary
Secondary
Traumatic
Tension
What is primary pneumothorax
Without and apparent cause and no significant lung disease
What is secondary pneumothorax
Related to an underlying lung disease such as COPD
What is traumatic pneumothorax
Caused by an trauma injury which allows air to leak into the pleural space
What is tension pneumothorax
Caused by trauma and mechanical ventilation which causes mediastinal shift
What is mediastinal shift
Mediastinum (division of the lung that contains the heart) is shifted and under great pressure
