6.4 Gas exchange

IB Syllabus Statements

Understandings:

Ventilation maintains concentration gradients of oxygen and carbon dioxide between air in alveoli and blood flowing in adjacent capillaries.
Type I pneumocytes are extremely thin alveolar cells that are adapted to carry out gas exchange.
Type II pneumocytes secrete a solution containing surfactant that creates a moist surface inside the alveoli to prevent the sides of the alveolus adhering to each other by reducing surface tension.
Air is carried to the lungs in the trachea and bronchi and then to the alveoli in bronchioles.
Different muscles are required for inspiration and expiration because muscles only do work when they contract.

Applications and skills:

Application: Causes and consequences of lung cancer.
Application: Causes and consequences of emphysema.
Application: External and internal intercostal muscles, and diaphragm and abdominal muscles as examples of antagonistic muscle action.
Skill: Monitoring of ventilation in humans at rest and after mild and vigorous exercise. (Practical 6)

How have epidemiological studies contributed to our understanding of the causes of lung cancer?
What does ventilation maintain between air in alveoli and blood flowing in adjacent capillaries?
Compare Type I and Type II pneumocytes and their role in gas exchange.
Outline how air moves to the lungs, and then to the alveoli.
Explain how muscle contractions ventilate the lungs.
Explain which muscles contract for inspiration and expiration.
Outline the causes and consequences of lung cancer.
Outline the causes and consequences of emphysema.
Explain how external and internal intercostal muscles, and diaphragm and abdominal muscles, are examples of antagonistic muscle action.
Explain how you would monitor ventilation in humans at rest and after mild and vigorous exercise. What two variables should be measured?
Explain how you would draw a diagram to show the structure of an alveolus and an adjacent capillary.