Kids Research Express

. Pharynx, muscular tube located in the neck, lined with mucous membrane, that connects the nose and mouth with the trachea (windpipe) and esophagus and serves as a passageway for both air and food. About 13 cm (5 in) long in humans, it lies in the front of the spinal column. The pharynx contains the tonsils and, in children, the adenoids . Because it begins in the back of the nasal cavity, the upper part of the pharynx is called the nasopharynx. The lower part, or oropharynx, refers to the area in the back of the mouth. The pharynx ends at the epiglottis , a flap of cartilage that prevents food from entering the trachea but allows it to enter the esophagus. Two eustachian tubes connect the pharynx to the middle ear and help equalize air pressure that builds up on the eardrums. The pharynx is subject to infections that enter through both the mouth and the nose. The symptoms of a sore throat generally involve inflammation or infection of the pharynx called pharyngitis. Causes of pharyn

. Air leaves the nasal passages and flows to the pharynx, a short, funnel-shaped tube about 13 cm (5 in) long that transports air to the larynx. Like the nasal passages, the pharynx is lined with a protective mucous membrane and ciliated cells that remove impurities from the air. In addition to serving as an air passage, the pharynx houses the tonsils, lymphatic tissues that contain white blood cells. The white blood cells attack any disease-causing organisms that escape the hairs, cilia, and mucus of the nasal passages and pharynx. The tonsils are strategically located to prevent these organisms from moving further into the body. One tonsil, called the adenoids, is found high in the rear wall of the pharynx. A pair of tonsils, the palatine tonsils, is located at the back of the pharynx on either side of the tongue. Another pair, the lingual tonsils, is found deep in the pharynx at the base of the tongue. In their battles with disease-causing organisms, the tonsils sometimes become swo