Wednesday 15 January 2014

The mechanism of breathing.

When volume is increased pressure is decreased.
Air rushes into areas of lower pressure.
So increasing volume in the lungs brings air in:

Breathing in (inspiration)
Diaphragm contracts: flattens- increasing volume.
Intercostal  muscles contract: pulling up and out- increasing volume.

When volume is decreased it increases pressure.
Air rushes to areas of lower pressure.
So if volume is decreased in the lungs air will rush out:

Breathing out (Expiration)
Diaphragm relaxes: becoming a dome shape and pushing up- decreasing volume.
Intercostal muscles relax: pushing the ribcage down and in- decreasing volume.


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