How do intercostal muscles aid in coughing?

Intercostal muscles aid in coughing by contracting and expanding, which changes the volume of the chest cavity to expel air forcefully.

The intercostal muscles are a group of muscles situated between the ribs. They play a crucial role in the mechanical aspect of breathing, including coughing. Coughing is a reflex action that clears the throat and lungs of mucus, foreign particles, irritants, and microbes. It involves a sudden, forceful expulsion of air from the lungs, and the intercostal muscles are instrumental in this process.

When you cough, the process begins with a deep inhalation. The intercostal muscles contract, pulling the rib cage upwards and outwards, which increases the volume of the chest cavity. This decrease in pressure allows air to rush into the lungs. Following this, the epiglottis (a flap of tissue at the base of the tongue) closes off the windpipe, and the muscles of the diaphragm, abdomen, and intercostal muscles contract rapidly.

This rapid contraction decreases the volume of the chest cavity and increases the pressure inside it. The closure of the epiglottis means that the high-pressure air in the lungs has nowhere to go, building up a significant amount of pressure. When the epiglottis opens, the high-pressure air is expelled forcefully from the lungs, carrying with it any irritants or mucus. This is what we recognise as a cough.

In essence, the intercostal muscles' ability to alter the chest cavity's volume and pressure is vital for the coughing process. By contracting and expanding, they enable the forceful expulsion of air needed to clear the lungs and throat. Understanding this process is not only important for biology but also for understanding the human body's responses to respiratory diseases and conditions.