Surfactant, Compliance and Lung Function Tests Flashcards
Type I alveolar wall cells
thin walled cells that permit gas exchange
Type II alveolar wall cells
secrete surfactant fluid
Surfactant
detergent-like fluid produced by alveolar type II cells
Surfactant function
reduced surface tension on alveolar surface membrane (therefore reducing the tendency for the alveoli to collapse)
increases lung compliance
reduced lung tendency to recoil
makes work of breathing easier
Surfactant is more effective in…
smaller alveoli
because surfactant molecules come closer together and therefore are more concentrated
Law of LaPlace
p = 2T/r
Surfactant production begins at
25 weeks gestation
complete at 36 weeks
Premature babies without surfactant can have
infant respiratory distress syndrome
Compliance
change in volume relative to change in pressure
High compliance is a
large increase in lung volume for a small decrease in ip pressure
Low compliance is a
small increase in lung volume for a large decrease in ip pressure
Pulmonary fibrosis
hardening
less compliance
inert fibrous tissues means effort of inspiration increases
emphysema
loss of elastic tissue means expiration requires effort
destruction of alveoli/ loss of elasticity
obstructive lung disease examples
emphysema
bronchitis
COPD
Influenza
Asthma
Fibrosis leads to a decrease in
compliance
