How does the respiratory system work?

Author: Sharon Jang | Reviewer: Tova Plashkes | Published: 24 September 2020 | Updated: 7 December 2021

The breathing process: During inhalation, the diaphragm (dark pink) moves down and the ribs expand. During exhalation, the diaphragm moves up and the ribs contract.¹

The respiratory system is responsible for helping you breathe in (inhaling) and out (exhaling). Breathing is done through the nose and mouth, although the nose is more often used. One reason the nose is used more often is because it acts as a filter for debris, which protects the lungs. Coughing is another important part of the respiratory system, as it helps to clear mucus from your lungs and airways.

Many muscles help with respiratory functions. The muscles used for inhaling are controlled from the spinal nerves of the neck (C3-C5 primarily), with some help from the nerves of the lower neck and thorax (C6-T12). Inhaling is mostly facilitated by your diaphragm, which is a large dome shaped muscle underneath the lungs. When you breathe in, your diaphragm lowers and the space in your chest increases, pulling air into the lungs. When you exhale, your ribs move back in and the diaphragm moves back up.

Breathing during exercise and coughing requires extra effort. To help, the abdominal muscles (over your belly) and the intercostal muscles (which help to squeeze the ribs) are activated, allowing for a stronger inhalation and a forceful cough.