Trachea into left and right main bronchi. The trachea begins level with the sixth cervical vertebra and the carina is found at the level of the fifth thoracic vertebra (T5), opposite the sternal angle and can be positioned up to two vertebrae lower or higher, depending on breathing. The trachea is surrounded by rings of hyaline cartilage; these rings are incomplete and C-shaped. The cricoid cartilage is attached to the first tracheal ring at top of the trachea and acts as the bottom of the larynx. There are fifteen to twenty rings in total, separated by narrow intervals. These reinforce the
Explorers of the Human Body weeks. It was later decided that instead of a hiatus, the program will end the season with thirteen episodes. Super Junior decided to leave the show due to their occupied schedules and busy preparations for their upcoming Asia-wide concert tour, Super Show. However, representatives of the program stated if there is a chance, a second season is considered. "Change", the variety program hosted by Lee Hyo-ri and Shin Dong-yup with Noh Hong-chul, Kangin, Son Ho-young and Min Kyung-hoon as regulars, took over the time slot. Explorers of the Human Body Explorers of the Human Body (Hangul: 인체탐험대; Hanja: 人體探險隊) was