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
Explorers of the Human Body Explorers of the Human Body Explorers of the Human Body (Hangul: 인체탐험대; Hanja: 人體探險隊) was one of the three shows of the newly revamped "Good Sunday", a lineup of variety shows that airs every Sunday evening at 5:30 pm KST on SBS. The show's aim was to answer curious questions about the human body, where the Super Junior members perform the answers by doing experiments with their own bodies. The show succeeded in attracting a wide audience due to its comedic and educational content. After previous popular shows "X-Man" and "Reverse Drama" ended, SBS's "Good Sunday" decided to air a