Lecture 31 Flashcards
how does compliance relate to elastance?
C=1/E
E=elastance
what is a disease where elastance is damaged?
emphysema= elastic recoil is lost and compliance is increased… low recoil
on the lung compliance curve which way does the curve shift if there is a lot of compliance?
left
How does decreased surface tension affect the compliance?
it increases the compliance shifting the curve left.
ex filling a lung with saline, eliminating surface tension
In pulmonary fibrosis how is the compliance of the lung?
the compliance is low, so the graph shifts right
What is Laplace formula?
P=4t/r
t=surface tension
r=radius
surface tension forms sphere and a pressure is developed inside bubble
4t= 2 surfaces like a bubble
2t= if 1 surface like alveoli
increase radius= decrease pressure
Laplace formula in alveoli?
P=2t/r
t=surface tension
r=radius
this is for alveoli= it looks like two balls.
forms a pressure gradient so air would flow from the smaller to larger alveoli
tendency would be for small alveoli to collapse and large alveoli to fill
whole regions of lungs may also remain collapse after expiration if not for surfectant
small alveoli develop ______ pressure
large
large alveoli develop______ pressure
small
what does surfectant do to surface tension and and compliance?
reduces surface tension and increases compliance.
it is the reason that alveoli do not collapse
think about equations..
P=2t/r low surface tension= low pressure
compliance= Volume/pressure
low pressure= high compliance
what is atlectaisis?
when at low lung volumes smaller alveolus collapse
what occurs during high lung compliance?
lung inflates easily and has little elastic recoil, curve shifts left…
what disorders are typical to high lung compliance?
emphysema and COPD
what occurs with low compliance?
lung inflates with difficulty because of large elastic recoil
graph shifts right
what disease have low compliance?
pulmonary fibrosis
Respiratory distress syndrome
