Gas Exchange

Alveoli:

- thin epithelial lining => short diffusion distance for respiratoey gases

- surrounded by capillaries => good blood supply

- large air spaces

- Elastic fibres => stretch during inhalation to maximise surface area, recoil during exhalation to ensure air is expelled

- Large surface area

Cartilage : prevents collapse of air ways

Ciliated epithelium: cilia sweeps mucus to top of trachea, back o the mouth to be swallowed so that pathogens can be…