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
The Human Body (TV series) July 2001 and includes a 50-minute feature on "The Making of the Human Body" - A final overview that reveals the techniques and developments that made the series possible. The series was adapted into a film released for IMAX cinemas. The film won the Giant Screen Theatre Association's Best Film For Lifelong Learning award. The book accompanying the series was written by Anthony Smith. According to one review, "Smith transcends anatomical trivia to record our bodies' powerful tale with empathy and clarity." The Human Body (TV series) The Human Body is a seven-part documentary series, first shown on 20 May