Although the ability to absorb colostrum is lost within a couple of days of birth, colostrum appears to still be capable of exerting a local effect on body surfaces such as the intestinal tract when it is eaten, or the skin and mouth when it is applied topically. 1  Most commercial colostrum preparations come from cows.
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.
The air sacs are very important because through them, the body receives oxygen and releases carbon dioxide. Dust that reaches the sacs and the lower part of the airways where there are no cilia is attacked by special cells called macrophages. These are extremely important for the defense of the lungs. They keep the air sacs clean. Macrophages virtually swallow the particles.