Structure of the Gas Exchange System

Question 1

RESPIRATORY BRONCHIOLES, ALVEOLAR DUCTS AND ALVEOLI

= about

Answer 1

• The only areas where gas exchange occurs.
• Respiratory bronchioles and alveolar ducts have outpouchings – alveoli
• They terminate in the alveolar sacs.
• There are about 23 generations of airway division between the larynx and the alveoli
• Larger airways are held open by cartilage
• Respiratory bronchioles are held open by elastic tissue → susceptible to collapse

Question 2

Alveoli characteristics

Answer 2

Alveoli are designed to maximise diffusion:
- Large surface area
- Very thin walls
- Large no.s of capillaries
Alveoli about one another and are surrounded by elastic tissue.