Alveolus Structure (Microscopic View)

Part of Gas Exchange in Humans · Section 4 of 19

DiagramUnit: OrganisationGCSE

This diagram covers Alveolus Structure (Microscopic View) within Gas Exchange in Humans for GCSE Biology. Lung structure, alveoli adaptations, breathing mechanism, gas transport in blood, and effects of smoking It is section 4 of 19 in this topic. Focus on the labels, the relationships between parts, and the explanation that turns the diagram into an exam-ready answer.

Alveolus Structure (Microscopic View)

Painted close-up of four alveoli clustered like soap bubbles, surrounded by crimson capillaries. Blue oxygen molecules move from air into blood; gold carbon dioxide molecules move from blood into air. Thin walls and rich blood supply ensure fast exchange.
O₂ O₂ O₂ CO₂ CO₂ CO₂ Alveolar Air Space O₂ diffuses into blood CO₂ diffuses from blood Capillary Network Wall thickness: 0.5 micrometers

Gas exchange at the alveolus - oxygen enters blood, carbon dioxide leaves

Practice questions for Gas Exchange in Humans

Which is the correct order of structures air passes through to reach the lungs?

  • A. Trachea → bronchi → bronchioles → alveoli
  • B. Bronchi → trachea → bronchioles → alveoli
  • C. Trachea → bronchioles → bronchi → alveoli
  • D. Bronchioles → bronchi → trachea → alveoli
1 markfoundation

Explain how the structure of alveoli is adapted for efficient gas exchange.

4 marksstandard

Quick recall flashcards

What is the trachea?
The main airway (windpipe) that carries air from the throat to the lungs, reinforced with cartilage rings
What are alveoli?
Tiny air sacs in the lungs where gas exchange takes place - oxygen enters the blood and carbon dioxide leaves

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Alveoli: The Sites of Gas Exchange

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The Breathing Mechanism

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