Elastic Properties Of Lung/Chestwall System

Question 1

Elastic properties of lung

Answer 1

Elastic fibers ⅓

Surface tension ⅔

Question 2

Changes in lung vol caused by

Answer 2

Changes in transmutation pressure

Pressure is independent variable

Question 3

Lung compliance

Answer 3

Ease which alveoli can fill with air
Lung has high compliance
Low at higher lung vol, high at lower vol
Depends on
1. Elastic properties
2. Amount of surface tension
3. Airway resistance

Question 4

Law of LaPlace

Answer 4

P = 2T/r
Need more pressure to maintain little alveoli compared to big alveoli
Thus surfactant decreases surface tension and prevent atelectasis

Question 5

Obstructive diseases

Answer 5

COPD, emphysema, bronchitis, asthma
Inc lung vol, dec elastic recoil, inc compliance, dec diffusion capacity
Inc TLC and RV and FRC

Question 6

Restrictive diseases

Answer 6

Fibrosis, kyphoscoliosis, pna, TB, edema, anthracosis
Dec lung vol, inc elastic recoil, dec compliance, dec diffusion capacity
Dec TLC and FRC

Question 7

Equilibrium point of breathing cycle

Answer 7

FRC
Point just before inspiration
Pressure of lung/chestwall system is zero