The Mechanics of Breathing
Physical Education: AQA GCSE, topic 1.2.7
Inhaling
Inhaling is the process of breathing in air by increasing the volume (amount of space within) of the chest cavity. The following changes happen to help increase the chest cavity volume:
Contraction of intercostals
- When we inhale, the intercostals (muscles between the ribs) contract. This causes the rib cage to rise up and outwards.
Contraction of diaphragm
- When we inhale, the diaphragm (the dome-shaped muscle at the base of the chest cavity) also contracts and flattens out.
Exhaling
Exhaling is the process of breathing out by reducing the volume of the chest cavity. Exhalation is passive because the muscles just relax.
Relaxation of intercostals
- When we exhale, the intercostal muscles relax. This causes the rib cage to fall and decreases the volume of the chest cavity.
Relaxation of diaphragm
- When we exhale, the diaphragm (the dome-shaped muscle at the base of the chest cavity) relaxes.
Test yourself on The Mechanics of Breathing
Which of the following happens during inhalation?
Which muscles contract during inhalation?
Which of the following happens during exhalation?
How would you describe the process of exhalation?
What is the name of the dome-shaped muscle at the base of the chest cavity?