what are the functions of a birds air sacs
The air sacs of birds extend into the humerus (the bone between the shoulder and elbow), the femur (the thigh bone), the vertebrae and even the skull. Birds do not have a diaphragm; instead, air is moved in and out of the respiratory system through pressure changes in the air sacs.Muscles in the chest cause the sternum to be pushed outward. This creates a negative pressure in the air sacs, causing air to enter the respiratory system.espiration in birds is much different than in mammals. Birds have a larynx, but it is not used to make sounds. Instead, an organ termed the syrinx serves as the voice box.. Birds have lungs, but they also have air sacs. Depending upon the species, the bird has seven or nine air sacs.