The Mechanics of Breathing 2
Physical Education: AQA GCSE, topic 1.2.8
Breathing During Exercise
During exercise, the body will try to maximise the inspiration (breathing in) and expiration (breathing out) processes. This helps us cope with the increased oxygen demands associated with exercise.
Inspiration
- In inspiration, the pectoral (chest) and sternocleidomastoid (neck) muscles contract to expand the lungs to allow more air in (increases chest cavity volume).
Expiration
- In expiration, the abdominal muscles contract to force air out of the chest cavity to speed up expiration, letting us breathe more quickly.
The Flow of Air
Air will always flow from an area of high pressure to an area of low pressure to create an equilibrium (balance).
Inhalation
- During inhalation, the volume of the chest cavity is increased, so a low pressure is created inside the chest.
- This causes air to rush into and fill the lungs.
Exhalation
- During exhalation, the volume of the chest cavity is decreased, so a high pressure is created inside the chest.
- This causes air to rush out of the lungs.
Test yourself on The Mechanics of Breathing 2
Which of these muscles contracts during expiration?
Which muscles contract during inspiration?
During which breathing process do the abdominal muscles contract?
Which of the following happens during exhalation?
What happens during inhalation?