The upper respiratory tract consists of the nose, the sinuses, and the pharynx. The pharynx has a large number of lymph gland distributed around, the important ones being the adenoids and the tonsils. The diseases encountered in this are viral or bacterial infections. These lymph glands do a very efficient job of arresting bacteria and viruses and get inflamed. Nose is the first organ the incoming air encounters. The hair in the nose filters out gross impurities. When there are overwhelming loads a large volume of mucus is produced to wash them out. This is the usual harmless common cold. Sinusitis. The air then enters the maxillary sinuses, frontal sinuses and the sigmoid sinuses where air gets warmed up, humidified and filtered of the fine particulate, bacterial and viral impurities. When there is overwhelming viral or bacterial load, the sinuses get inflamed and causes the often bothersome sinusitis. In severe cases, one needs to resort to antibiotics or even surgical intervention. Pharyngitis is the inflammation of the lymphatic glands there. The important ones are adenoids and tonsils. Severe cases one has to undergo their surgical removal. The lower respiratory tract diseases are diseases affecting the organs below the level of the larynx.