The trachea, colloquially called the windpipe, is a cartilaginous tube that connects the pharynx and larynx to the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea the cricoid cartilage attaches it to the larynx. This is the only complete tracheal ring, the others being incomplete rings of reinforcing cartilage. Human tracheal epithelial cells (HTEpiC) are a useful in vitro model for studying the function and pathophysiology of respiratory epithelium. HTEpiC also useful tools to stablish in vitro disease models for High Throughput and High Content Screening.