The lung as an organ of exchange
Learning intentions
• Describe the features of an efficient exchange
surface with reference to diffusion of oxygen
and carbon dioxide across an alveolus.
• Describe the features of the mammalian lung
that adapt it to efficient gas exchange.
• Outline the mechanism of breathing.
The Lungs
How lungs are adapted for exchange
Adaptation
Importance for gas
exchange
Breathing
Breathing
Questions
• State three ways in which the structure of the
lungs allows efficient gas exchange
• Explain why the barrier to diffusion must be as
thin as possible
• Describe how a steep diffusion gradient is
achieved in the lungs.
Lesson 2: Tissues in the lungs
Learning Intentions
• Describe the distribution of cartilage, ciliated
epithelium, goblet cells and smooth muscle
and the elastic fibres in the trachea, bronchi
and bronchioles and alveoli
• Describe the functions of cartilage, cilia,
goblet cells, smooth muscle and elastic fibres
in the mammalian gaseous exchange system.
Starter
• In order for air to enter the lungs through the
trachea, bronchi and bronchioles, what
features do you think they must have?
• Students will be able to look at various slides
of these structures
Tissues in the lungs
Goblet cells
CILIATED EPITHELIUM
Ciliated epithelium
Ciliated epithelium
Role of each tissue
TISSUE
Cartilage
Smooth Muscle
Elastic Fibres
Goblet cells and
glandular tissue
Ciliated
epithelium
ROLE
WHERE IS IT
FOUND
Questions
• Explain the importance of the cartilage found
in the trachea and bronchi.
• Describe the action of the cilia and mucus in
helping to reduce the risk of infection
• The action of smooth muscle and elastic fibres
in the bronchioles can be described as
antagonistic. Explain the meaning of this term
using this example to illustrate your answer.
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The lung as an organ of exchange