6 Surfactant Flashcards
what generates distending pressure?
elastic recoil forces of the lung and chest wall
What determines lung elasticity?
elastic properties of lung tissue
chest wall properties (rigidity
What dos arthritic spondylitis do to chest wall compliance?
decreases it, as there is long-term arthiritis in the spine
How would fluid filled lung compliance differ from air filled lung compliance?
it would increase compliance
How much of lung elasticity is down to surface tension?
2/3
What is laplace’s law?
P = 2T / r
WHat is the significance of laplace’s law?
smaller bubbles need a greater internal pressure to keep them inflated, so smaller alveoli empty into bigger ones, decreasing SA
What is alveolar interdependence?
they empty into each other
What does surface tension do to compliance?
decreases compliance
What is the main constituent of surfactant?
dipalmitoyl phophatidylcholine (phospholipid)
Would a larger alveoli or smaller one hav more DPPC?
smaller, as there is a higher pressure so surface tension needs to be decreased more
what is the difference between surfactant and detergent?
surfactant can alter their surface tension - lowering effect
What happens to surfactant following expiration, and how does this effect compliance?
less surfactant is at the air-fluid interface, so compliance is lower
What is the definition of airflow resistance?
the pressure difference required for a given flow
How can the work overcome airflow resistance?
increase lung volume, stretching it, changing the distending pressure
