Phys Chapter 16

Conduction zone

air in

Respiratory zone

gas exchange

Alveoli Type I

gas exchange

Alveoli Type II

surfactant production

Surfactant

reduces surface tension to prevent alveolar collapse

Intrapulmonary Pressure

Pressure within alveoli

Intrapulmonary Expiration

-1cmH2O

Intrapulmonary Inspiration

+1cmH2O

Intrapleural Pressure

Pressure in pleural cavity

Intrapleural Expiration

-5cmH2O

Intrapleural Inspiration

-8cmH2O

Transpulmonary Pressure

Pressure difference between intrapleural/ pulmonary

Transpulmonary Expiration

+6 cmH2O

Transpulmonary Inspiration

+7 cmH2O

Inspiration process

Diaphragm contracts (flattens), external intercostals raise rib cage → thoracic volume ↑ → intrapulmonary pressure ↓ → intrapleural pressure ↓ → air in

Expiration process

diaphragm and intercostals relax → volume ↓ → intrapulmonary/pleural pressure ↑ → air out

Dalton's Law

total pressure = sum of individual gas pressures

Henry’s Law

amount of gas dissolved ∝ partial pressure and solubility