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
What Is Life "Rolling Stone" readers' poll, titled "10 Greatest Solo Beatle Songs", the song placed fourth, with the editor commenting: "The track is deceptively simple, and more layers become apparent the more often you play it." "What Is Life" has featured in Bruce Pollock's book "The 7,500 Most Important Songs of 1944–2000", Treble website's "The Top 200 Songs of the 1970s" (ranked at number 101) and Dave Thompson's "1000 Songs That Rock Your World" (at number 247). "What Is Life" was included on the 1976 compilation "The Best of George Harrison" as well as 2009's "". The song has also been featured