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
Theology of the Body nature of human beings in relation to God. The "Theology of the Body" presents an interpretation of the fundamental significance of the body, and in particular of sexual differentiation and complementarity, one which aims to challenge common contemporary philosophical views. Nevertheless, the pope's personalistic phenomenology is "echoing what he learned from St. John of the Cross" and is "in harmony with St. Thomas Aquinas". Francis Bacon was an early empiricist who focused on problems of knowledge. In his Great Instauration, he argued that the current state of knowledge is immature and not advancing. His purpose was for the human mind