Lung and chest wall

Question 1

Lung and chest wall:

tendency

Answer 1

for lungs to collapse inward,

for chest wall to spring outward

Question 2

At FRC: power balance

Answer 2

(volume in lung after normal expiration)

Inward pull of lung is balanced by outward pull of chest wall, and systemic pressure is atmospheric.

Elastic property of both chest wall and lungs determine their combined volume.

Question 3

At FRC: pressure balance

Answer 3

(volume in lung after normal expiration)

Airway and alveolar pressures are 0,
intrapleural pressure is negative (prevents PTX)

Question 4

Compliance

Answer 4

Change in lung volume for a give change in pressure;

LOW: pulm fibrosis, pneumonia, and edema.
HIGH: emphysema, and normal aging.