Q. : What are the tonsils?

Ans. : The pharynx is the continuation of the nose and mouth. It is a muscular tube that continues downwards through the neck and is responsible for the passage of both air (to the larynx, trachea and lungs) and food (to the oesophagus and then stomach). The pathways for food and air cross over in the pharynx. In addition, the auditory canal opens onto the upper part of the pharynx. The walls of the pharynx are composed of fascia and muscle layers all lined by a mucous membrane. The pharynx is divided into three different areas based on anatomical location: the nasopharynx (behind the nose); oropharynx (behind the mouth); and the laryngopharynx (behind the larynx). The tonsils are a ring of lymphoid tissue around the upper part of the pharynx. They consist of the lingual tonsil in the posterior part of the tongue, the palatine tonsils and the pharyngeal tonsils. Lymphoid tissue acts as a barrier against infection.