And the cilia are continually moving in a wavelike fashion. And what the cilia ultimately do is they move these pathogens which are trapped inside the mucus all the way up to our pharynx. And from the pharynx we can actually spit out the mucus along with the pathogens or we can swallow it and the mucus and the pathogens will ultimately end up in our stomach. Now, why would we want to basically take that pathogen and place it in our stomach as a result of swallowing? Well, because inside our stomach we have parietal cells and these parietal cells basically secrete gastric acid, hydrochloric acid, HCL. And this HCL creates a very acidic environment inside our stomach and most bacterial cells and pathogens will not survive in this acidic environment.