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
Unethical human experimentation in the United States ashes analyzed for radioisotopes. This project was kept secret primarily because it would be a public relations disaster; as a result parents and family were not told what was being done with the body parts of their relatives. Between 1960 and 1971, the Department of Defense funded non-consensual whole body radiation experiments on mostly poor and black cancer patients, who were not told what was being done to them. Patients were told that they were receiving a "treatment" that might cure their cancer, but the Pentagon was trying to determine the effects of high levels of radiation on the human