• Created by: Leigh. x
  • Created on: 11-10-12 20:43

Breathing In

When we breath in the intercostal muscles and the diaphram contract. This means the diaphram flattens & the rib cage & sternum move up and out. This makes the volume of the thorax increase in size which causes a decrease in pressure. Air is then drawn into the lungs

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breathing out

Breathing out occurs when the intercostal muscles & the diaphram rises. This means that the ribs and Sternum move in and down, as a result the volume of the thorax decreases and the pressure increases meaning that the air is forced out of the lungs.

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