Respiratory Physiology Part 2 Flashcards
muscles of breathing
diaphragm
abdominals
internal intercostals
diaphragm effect on breathing
when diaphragm contracts the abdominal contents are pushed down and ribs are lifted upward and outward
increases intrathoracic volume
diaphragm increase intrathoracic volume which in turn causes ___
decreases intrathoracic pressure and initiates flow of air into lungs
abdominals on breathing
compress abdominal cavity and push diaphragm up
internal intercostals on breathing
pulls rib downward and inward
function of expiratory muscles during exercise or disease
during an increase in airway resistance these muscles aid in the expiratory process
compliance
- distensibility of the system
- how volume changes as a result of pressure change
- inversely correlated with elastance
measuring lung compliance
requires simultaneous measurement of lung pressure and volume
transmural pressure
pressure across a structure
pressures equal to atmospheric pressure
zero
pressure higher than atmospheric pressure
positive
pressures lower that atmospheric pressure
negative
Hysteresis
term used to describe the difference between inspiratory and expiratory compliance. Lung volume at any given pressure during inhalation is less than the lung volume at any given pressure during exhalation. Hysteresis is present in both static and dynamic lung compliance curves.
why are inspiration and expiration curves different?
hysteresis
the intermolecular forces between liquid molecules lining the lung are much stronger than the forces between liquid and air molecules
pneumothorax
sharp object punctures the intrapleural space
intrapleural pressure = atmospheric pressure
2 consequences of pneumothorax
lung collapse
chest wall expands
Volume is FRC
lungs wants to collapse
chest wall wants to expand
The combined lung and chest wall system NEITHER has a tendency to collapse NOR to expand
Volume is less than FRC
forced expiration
- there is less volume in the lungs and the collapsing force of the lungs is smaller
- expanding force on chest wall is greater
combined system “wants to expand”
Volume is greater than FRC
subject inspires
- more volume in the lungs / collapsing force is greater
- expanding force in chest wall is smaller
combined lung and chest wants to collapse
diseases of lung compliance
emphysema
fibrosis
Emphysema
increase lung compliance
COPD - loss of elastic fibers
Fibrosis
decreased lung compliance
restrictive disease
Emphysema effect on Volume is FRC
tendency for lungs to collapse is less than the tendency for the chest wall to expand
How to balance out emphysema effect on Volume is FRC
volume must be added to increase their collapsing force
needs higher FRC