Changes

*Avian [[Lungs - Anatomy & Physiology|lungs]] are relatively small, with a bird's lungs being approximately 50% as large as the lung of a mammal of a similar size. The lungs are unlobed and do not have the capacity to expand.

*Avian [[Lungs - Anatomy & Physiology|lungs]] are relatively small, with a bird's lungs being approximately 50% as large as the lung of a mammal of a similar size. The lungs are unlobed and do not have the capacity to expand.

*The lungs are positioned in the craniodorsal region of the body, and are deeply indented by both the thoracic [[Spinal Column - Anatomy & Physiology#Vertebrae and Joints|vertebrae]] and [[Ribs and Sternum - Anatomy & Physiology|ribs]].

*The lungs are positioned in the craniodorsal region of the body, and are deeply indented by both the thoracic [[Spinal Column - Anatomy & Physiology#Vertebrae and Joints|vertebrae]] and [[Ribs and Sternum - Anatomy & Physiology|ribs]].

*Birds do not have a [[Pleural Cavity and Membranes|pleural cavity]] as the lungs do not expand, thus the membranes are not necessary.

*Birds do not have a [[Pleural cavity and membranes|pleural cavity]] as the lungs do not expand, thus the membranes are not necessary.

 

==Air Sacs==

==Air Sacs==