trachea with mucus, catarrh, 3d section. human anatomy

accumulate accumulation anatomy annular bacteria body breathing cartilage catarrh colds connective difficulties difficulty discomfort duct exploration fever fibrous from human inflamed ligaments lungs mucosa mucous mucus muscle obstruction organs outside pain parts rendering respiratory rings science section serves structure structures study swallow swallowing symptoms that tissue tonic tonka trachea tract training transfer tube with