How do we breathe in?

The scientific term for breathing in is inspiration. The main muscle that helps us to breathe is called the diaphragm; a large, dome shaped muscle that sits below our rib cage. The external intercostal muscles also help us to breathe, though they don't have as much influence as the diaphragm. These muscles are the outer parts of the intercostal muscles, which sit between our ribs. *show diagram positioning diaphragm and intercostal muscles.*Inspiration is a passive process, and is a result of changes in pressure within the thoracic cavity, which is where the lungs sit. There are 2 gas laws that you need to know to understand inspiration. The first is that when the volume of a space increases, the pressure inside decreases. The second is that gas will move from an area of high pressure to low pressure. This is why the mechanism of inspiration works. The diaphragm contracts and flattens out, pushing down the organs below. The external intercostal muscles also contract, and pull the rib cage upwards and outwards. This increases the size of the thoracic cavity, reducing the pressure to below the atmospheric pressure. Air then rushes from high to low pressure, down the trachea and into the lungs. Do you have any questions about that? ask them to repeat it back to me.