Relaxation Pressures Flashcards
The decrease of volume in the lungs and thoracic cavity is due to which 4 forces?
- Gravity
- Muscle relaxation
- Elasticity of lungs
- Torque
What kind of pressures are restoring forces able to produce in the respiratory system?
- PASSIVE (relaxation) pressures
The magnitude of Relaxation Pressures produced depends on what?
- the volume of air trapped in the closed respiratory system
- how far away the respiratory system is pushed from its resting point
How is the relaxation pressure curve created?
- measuring lung pressure at different points along a person’s vital capacity using a manometer
- subject actively breathes to a set % of their VC then relaxes completely and allows passive air pressure thats created by restoring forces to displace the column of water in the U-tube.
According to the relaxation pressure curve, what is happening at 60% VC?
- There is 10 cmH2O of pressure
- inspiratory muscles are needed to overcome relaxation pressure
- muscles get smaller when relaxed
According to the relaxation curve, what is happening at REL?
- all muscles are relaxed
- 0 cmH2O
- no air in, no air out
According to the relaxation curve, what is happening at 30% VC?
- expiratory muscles are needed to overcome pressure
- -4 cmH2O
- air wants to flow in
In order to get higher than REL what must happen?
- use inspiratory muscles
- to increase lung volume
- expand rib cage
- inhale
In order to get lower than REL, what must happen?
- use expiratory muscles
- decrease volume of lungs
How much of your VC will the lung-rib system compromise at resting state?
~35-38%
For speech breathing, exhalation is an..
ACTIVE muscular process
- muscular forces are used to control necessary pressures for speech
For life breathing, exhalation is…
PASSIVE
