Atelectasis is composed of 78% nitrogen and 21% oxygen. Since oxygen is exchanged at the alveoli-capillary membrane, nitrogen is a major component for the alveoli's state of inflation. If a large volume of nitrogen in the lungs is replaced with oxygen, the oxygen may subsequently be absorbed into the blood, reducing the volume of the alveoli, resulting in a form of alveolar collapse known as absorption atelectasis. It is usually associated with accumulation of blood, fluid, or air within the pleural cavity, which mechanically collapses the lung. This is a frequent occurrence with pleural effusion, caused by congestive heart failure (CHF).
Body language of dogs tail, the ears, and the head/body. Tail-wagging is a common tail movement used by dogs to communicate. Additionally, ear flattening or heightening are typical movements made using the ears. In terms of the head/body, it is of interest to study turning of the head, as well as the overall posture of the dog. Because dogs communicate differently than humans, it is more difficult for humans to interpret their emotional states. By focusing on the combinations of motions made by dogs, and studying the aftermath of such sequences, humans are able to attribute different emotional states (i.e., contentment, fear, or aggression)