L10- compliance

Question 1

compliance meaning

Answer 1

-change in lung vol due to a change in Pdist

Question 2

formula for compliance

Answer 2

change in vol (y axis)/change in Pdist (x axis)

Question 3

what does it mean if the complaince is increased

Answer 3

-easier for the lung to inflate so can breath more easily

Question 4

factors determining lung complaince

Answer 4

• stretchibility of tissue so more elastin means more compliance
• surface tension in the alveoli

Question 5

what is meant by alveolar interdependence

Answer 5

if one alveoli is affected, others are affected too

Question 6

where is the surface tension produced in the alveolo

Answer 6

• caused by the fluid lining the alveoli

- generates a collapsing force (making the alveoli smaller) and increases work of breathing

Question 7

laplace law formula

Answer 7

Pressure = 2tension/radius

- so if the radius decreases, the tension and pressure increases

Question 8

if there’s ST in the alveoli that could make the alveoli collapse, why doesn’t it happen

Answer 8

it has surfactant - a substance that reduces the ST in the alveoli
- by having a strong attraction for each other instead for other molecules

Question 9

what cells secretes surfactant

Answer 9

type 2 pneunocytes

Question 10

functions of surfactant

Answer 10

• lowers ST so increasing compliance
• keeps lungs dry
• helps alveolar stability (prevents collapsing of alveoli)

Question 11

what happens if there is no surfactant

Answer 11

• decreases compliance
• higher elastic recoil
• alveolar collapse
• hypoxia and hypercapnia