Related by context. Frequent words. (Click for all words.) 65 mucous membranes 62 nasal passages 61 digestive tract 61 lungs 60 gastrointestinal tract 59 upper respiratory tract 59 mucous membrane 57 GI tract 56 intestinal tract 56 nasal cavity 56 intestines 56 respiratory infections 55 urinary tract 55 respiratory 55 airway inflammation 55 respiratory tract infection 54 pharynx 53 intestine 53 lung inflammation 52 mucosa 52 sinuses 52 duodenum 52 chronic cough 52 lung tissue 52 secretions 52 trachea 51 mucus 51 throat irritation 51 asthma bronchitis 51 epithelium 51 bloodstream 51 inhaled 51 respiratory symptoms 51 aerosolized 50 bronchial 50 esophagus 50 airways 50 bronchiolitis 50 inhalation 50 digestive 50 digestive tracts 50 reproductive tract 50 lung 50 inflammation 50 blood vessels 50 lung infections 50 respiratory ailments 49 fungal spores 49 tissues 49 respiratory diseases 49 mucous 49 salivary glands 49 pollens 49 RSV infection 48 pneumococcus 48 airway 48 oral cavity 48 skin irritation 48 nostrils 48 secretion 48 small intestine 48 histamine 48 gastro intestinal 48 respiratory illnesses 48 epithelial cells 48 abdominal cavity 48 lung diseases 48 circulatory system 48 Inhaling 48 upper airway 48 rhinitis 48 allergic diseases 47 peripheral nerves 47 respiratory distress syndrome 47 mold spores 47 bacterial infection 47 respiratory distress 47 eye irritation 47 alveolar 47 gastrointestinal 47 inflammations 47 pet dander 47 fever nausea 47 pathogenic 47 mucosal 47 gastric ulcers 46 sinusitis 46 dermis 46 P. aeruginosa 46 atopic dermatitis 46 chronic lung 46 sweat glands 46 neutrophils 46 skeletal muscles 46 pulmonary diseases 46 otitis media 46 viral infections 46 eosinophils 46 Inhaled 46 lymphatic system 45 cerebrospinal fluid