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
What Is Life Harrison performances" (just three of which date from the ex-Beatle's solo years) and described the track as an "exultant song of surrender", abetted by Harrison's "pumping fuzz guitar" and the song's "singalong magnetism". AllMusic's Richie Unterberger similarly praises "What Is Life" for its "anthemic" qualities, "particularly snazzy horn lines", and a guitar riff that is "one more entry in the catalog of George Harrison's book of arresting, low, descending guitar lines". Writing in the book "1,000 Recordings to Hear Before You Die", author Tom Moon refers to "the upbeat single 'What Is Life'" as an example of how Harrison "grabs