Gas exchange

Topic 6.4

Essential idea: The lungs are actively ventilated to ensure that gas exchange can occur passively.


What is the relationship between ventilation, gas exchange and cellular respiration?

Diagram of ventilation, gas exchange and cellular respiration

6.2.U1 Ventilation maintains concentration gradients of oxygen and carbon dioxide between alveoli and blood flowing                      in adjacent capillaries

Definition of ventilation

6.2.U2 Type I pneumocystes are extremely thin alveolar cells that are adapted to carry out gas exchange

Type I pneumocytes in the Alveolus

6.2.U3 Type II pneumocyted secrete a solution containing surfactant that creates a moist surface of the alveoli to prevent                      the sides of the alveolus adhering to each other by reducing surface tensions

Type II pneumocytes in the Alveolus

6.2.U4 Air is carried to the lungs in the trachea and bronchi and then to the alveoli in bronchioles

Can you label the structures shown below in the figure?

Place your mouse on the diagram to view the labels of parts of the lung.

lung structure unlabelled

6.2.U5 Muscle contractions cause the pressure changes inside the thorax that force air in and out of the lungs to ventilate them

Changes in lung pressure when breathing in and breathing out

6.2.U6 Different muscles are required for inspiration and expiration because muscles only do work when they contract

breathing link
Changes in lung pressure when breathing in and breathing out


6.2.A1 Causes and consequences of lung cancer

Causes and consequences of cancer

6.2.A2 Causes and consequences of emphysema

Causes and consequences of cancer

6.2.A3 External and internal intercostal muscles, and diaphragm and abdominal muscles are examples of antagonistic muscle action

Action of antagonistic muscles


6.1.S1 Monitoring of ventilation in humans at rest and after mild and vigorous exercise

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