Trachea annular ligaments of trachea. The epiglottis closes the opening to the larynx during swallowing. The trachea develops in the second month of development. It is lined with an epithelium that has goblet cells which produce protective mucins (see "Respiratory epithelium"). An inflammatory condition, also involving the larynx and bronchi, called croup can result in a barking cough. A tracheotomy is often performed for ventilation in surgical operations where needed. Intubation is also carried out for the same reason by the inserting of a tube into the trachea. From 2008, operations have experimentally transplanted a windpipe grown by stem cells, and
Explorers of the Human Body new educational program, introducing the audience to the human body. Shin Dong-yup was chosen to be the lead MC, with the Super Junior members being regulars and co-MCs of the program. Ratings for the show became the highest of all three shows that aired in SBS's new "Good Sunday" lineup as the show is educational and entertaining to watch. It was also the first and currently the only variety show that included every member of Super Junior as regulars. Each episode has a main topic to explore regarding the human body. In the first episode, which involved the tongue and