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) programmes on the human body. The series was produced by Richard Dale and presented by Professor Robert Winston, a fertility expert. The series used a variety of different techniques to present the topics being discussed, including endoscopes and computer graphics for internal shots, time-lapse photography to show the growth of hair and nails, magnetic resonance imaging and scanning electron microscopy. The series gained 6.3 million viewers and an audience share of 38%. The series was nominated for numerous awards, winning several, including three BAFTA awards, four RTS awards and a Peabody Award. A DVD of the series was released in