Trachea to prevent swallowed matter from entering the trachea. In the fourth week of development of the human embryo as the respiratory bud grows, the trachea separates from the foregut through the formation of tracheoesophageal ridges which fuse to form the tracheoesophageal septum and this separates the future trachea from the oesophagus and divides the foregut tube into the laryngotracheal tube. Before the end of the fifth week, the trachea begins to develop from the laryngotracheal tube which develops from the laryngotracheal groove. The first part of the cephalic region of the tube forms the larynx, and the next part forms
History of beliefs about the human body these views, that the soul has aspects that can't be felt by normal methods, and physical manifestations that can be felt. "For even if one and being are spoken of in several ways, what is properly so spoken of is the actuality" -Aristotle in DeAnima Aristotle forms the idea of Hylomorphism, that the soul and the body are not capable of being split apart without destroying both in the process. Despite this idea of the body and the soul Aristotle viewed disorder in what could be seen and felt. He was a proponent of the humoral theory that classified disorder