Trachea act as a resonator to amplify sound. In some birds, the tracheal rings are complete, and may even be ossified. In amphibians, the trachea is normally extremely short, and leads directly into the lungs, without clear primary bronchi. A longer trachea is, however, found in some long-necked salamanders, and in caecilians. While there are irregular cartilagenous nodules on the amphibian trachea, these do not form the rings found in amniotes. The only vertebrates to have lungs, but no trachea, are the lungfish and the "Polypterus", in which the lungs arise directly from the pharynx. The word "trachea" is used to
History of beliefs about the human body manuscript is recorded in the Yellow Emperors Inner Cannon, and it being recorded in this way represents the attention to the individuals perspective in creating therapies like acupuncture to treat body ailments. The Inner Cannon was revised by natural Philosophers of the time and the approved version of the Han Court and became a foundational text for the ideals and perceptions of the human body. It focused on Qi, Yin and Yang balance, and Five phase theory to explain health can disease. Referred to as the life force of the body, or the means by which the body is able