Zoom into a single air sac and the capillary hugging it. The wall between them — the respiratory membrane — is thinner than a soap bubble, so gases cross in a fraction of a second. Tap each part.
Alveolar space
The alveoluswhere gases cross
The parts
📷 Reference image
A real labeled figure to compare with the interactive above.
The Alveolus — OpenStax, CC BY 3.0 (via Wikimedia Commons)
