Like the nose, lungs have odor receptors. But instead of sending nerve impulses to the brain that conjure up a burning cigarette or a cup of coffee, these receptors send a signal that may make you cough. Unlike the receptors in your nose, which are located in the membranes of nerve cells, the ones in the lungs are in the membranes of the flask-shaped neuroendocrine cells that at times are triggered to dump hormones that make airways constrict.
— Futurity, reporting on new research from Washington University in St. Louis and the University of Iowa. Read more at Odor 'Guards' in Lungs Can Make Us Cough.