Friday 22 February 2013

2.45 understand the role of the intercostal muscles and the diaphragm in ventilation

Breathing in
The intercostal muscles contract
The ribs move up and out
The diaphragm contracts and moves down
The trachea carries air towards the lungs; it splits into two bronchi- one leading to the left lung, and one o the right- which then split into even smaller tubes, called bronchiles; these end in alveoli where gas exchange takes place.
The pleural membranes prevent friction.

Breathing out
The intercostal muscles relax
The ribs drop down
The diaphragm also relaxes and moves upward
These things reduce the space inside the lungs, pushing the air out.

5 comments:

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  2. The Biology Syllabus has changed.... New Syllabus Blog:

    http://igcse-biology-2017.blogspot.hk

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  3. more at

    http://igcse-biology-notes.blogspot.hk/2017/06/245-understand-role-of-intercostal.html

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