Trachea are generally highly elastic but they may calcify with age. The trachealis muscle connects the ends of the incomplete rings and contracts during coughing, reducing the size of the lumen of the trachea to increase the rate of air flow. The esophagus lies posteriorly to the trachea, adjoining along the tracheoesophageal stripe. Circular horizontal bands of fibrous tissue called the annular ligaments of trachea join the tracheal rings together. The cartilaginous rings are incomplete to allow the trachea to collapse slightly so that food can pass down the esophagus. A flap-like epiglottis closes the opening to the larynx during swallowing
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