Mechanics of breathing Flashcards
Which part of the nervous system controls breathing?
Autonomic nervous system
List a muscle associated with inspiration
Diaphragm
External IC - increase thorax diameter
Internal IC muscles are expiratory or inspiratory
Expiratory
The diaphragm is innervated by which nerve?
Phrenic nerve
During active expiration, the abdominal muscles push the diaphragm ____________ (up/down)
Upward
The measure of the lung’s ability to stretch and expand is called ______________
Compliance
Compliance =
Volume / pressure
T/F there is a point in the cycle where the volume of the lungs is 0
False
What is the term for the difference in volume and pressures during breathing?
Hysteresis
Is the lung more or less compliant at high lung volumes?
less
Emphysema and pulmonary edema can mean an increase or decrease in compliance?
Increase
What 2 things make the lungs compliant?
- collagen
- fibers of elastin
What is the primary reason for lung recoil?
Surface tension
pressure inside alevoli is (inversely proportional or directly proportional) to radius
Inversely proportional
Smaller alveoli can’t inflate the larger one due to what?
Surfactant
What is inversely proportional to flow in a tube?
Length
List some factors that determine airway resistance
- lung volume
- Bronchial muscle contraction
- density/viscosity of inspired gas
What 2 things influence ventilation?
- Compliance
- resistance
How is work measured?
Pressure x volume
Inspiration is active or passive
Active
Expiration is passive or active
Passive
There is an increased work with a decrease in ?
Lung compliance
O2 cost of quiet breathing is around?
5%
