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
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