And what the lysosome essentially does is it breaks down the cell walls of bacterial cells killing off those bacteria. So in our saliva and in our tears we find this proteolytic enzyme called lysozyme which essentially kills off bacterial cells. Now let's move into our passageways the air passageways of our body. And this includes the nasal cavity inside our nose the trachea, the windpipe as well as the bronchi and our bronchioles. So along these air passageways we have specialized types of cells called goblet cells. And these goblet cells basically secrete a special type of slimy and mucus like material we call the mucus membrane.