A bird’s respiratory system is inetresting because there is a one way flow. The air enters through the mouth then to the trachea, then the air sacs and bones then to the lungs where it leaves through the cloaca.
The air goes through a one way flow where the lungs decrease in inhalation but increase in exhalation. The air-sacs are thin walled. During inhalation, the prosterior air sacs receive air then it goes to the lungs where it then goes to the anterior air sacs which get blown out. The bird has a continuous amount of air in it’s body.
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