Respiratory Mechanics Flashcards
what is the muscle of quiet breathing?
diaphragm
during inspiration, the diaphragm ____
contracts
during expiration, the diaphragm ____
relaxes
what are the muscles of forced inspiration (extra respiratory drive)?
- external intercostals
- SCM
- scalenes
- serratus anterior
what are the muscles of forced expiration (extra respiratory drive)?
- internal intercostals
- abdominals
what muscle is most effective at producing maximal effort?
Rectus abdominis
what do the external intercostals do?
elevate the ribs for inspiration
what do the internal intercostals do?
depress the ribs during expiration
what effect does sympathetic stimulation have on the lungs?
dilates bronchi
what NT is released at sympathetic nerve endings at the lungs?
NE/E
what receptor do NT of sympathetic nerve endings at the lungs act on?
beta adrenergic
what effect does parasympathetic stimulation have on the lungs?
constricts bronchi
what NT is released at parasympathetic nerve endings at the lungs?
ACh
what receptor do NT of parasympathetic nerve endings at the lungs act on?
muscarinic (lung parenchyma)
what is the alveolar pressure at the beginning of inspiration?
0
what is the alveolar pressure during inspiration?
-1
what is the alveolar pressure at the end of inspiration?
0
what is the alveolar pressure during expiration?
+1
what is the alveolar pressure at the end of expiration?
0
what is the plural pressure at the beginning of inspiration?
-5
what is the plural pressure at the end of inspiration?
-8
what is the plural pressure at the end of expiration?
-5
what is the transpulmonary pressure at the beginning of inspiration?
+5
what is the transpulmonary pressure at the end of inspiration?
+8
what is the transpulmonary pressure at the end of expiration?
+5
what is compliance?
ability of the lung to expand
what increases compliance?
decreased surface tension
what is responsible for 2/3 of the ability to reduce surface tension?
pulmonary surfactant
what cells make surfactant?
type II alveolar cells
what is the biochemical name of surfactant?
dipalmitoyl phosphatidyl choline
surfactant also contains ____ and ____
apoproteins
Ca++ ions
in a preterm infant without pulmonary surfactant, what changes occur to alveolar surface tension and pulmonary compliance compared to a normal infant?
- alveolar surface tension increases
- compliance decreases
what changes occur to lung compliance and surfactant levels in a premature infant with respiratory distress syndrome?
- decreased compliance
- decreased surfactant
