Trachea the trachea. The trachea is no more than 4mm diameter during the first year of life, expanding to its adult diameter by late childhood. The trachea is more mobile and of more variable length, deeper, and smaller in children. The trachea is lined with a layer of pseudostratified ciliated columnar epithelium. The epithelium contains goblet cells, which are glandular, modified simple columnar epithelial cells that produce mucins, the main component of mucus. Mucus helps to moisten and protect the airways. Mucus lines the ciliated cells of the trachea to trap inhaled foreign particles that the cilia then waft upward toward
Less Commonly Taught Languages Less Commonly Taught Languages Less Commonly Taught Languages (or LCTLs) is a designation used in the United States for languages "other than" the most commonly taught foreign languages in US public schools. The term covers a wide array of world languages (other than English), ranging from some of the world's largest and most influential languages, such as Chinese, Russian, Arabic, Hindi, Portuguese, Japanese, Persian, and Turkish, to smaller regional languages studied in the US mainly by area experts, such as Twi, spoken in West Africa, and Finnish. The term arose out of a need to contrast the more commonly taught