Youtor
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=DYEKKyA7g5k
Twitter: / science_sauce • Breathing occurs through changes in pressure. The we breath one, the diaphragm contract and moves downwards. Meanwhile the external intercostal muscles contract, moving the ribcage upwards and outwards. This increases the volume in the thoracic cavity and therefore decreases the pressure. The pressure immediately balances by filling the lungs with air. • When we breath out, the diaphragm relaxes and is allowed to move upwards. At the same time, the internal intercostal muscle contract (and the external intercostal muscles relax), which decreases the volume, increases the pressure, and forces air out of the lungs.
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