Throat

The mouth (oral cavity) starts in front at the lips and extends behind the soft palate to the back of the throat (pharynx). It contains the tongue and teeth, whilst the main salivary gland ducts open in the floor of mouth under the tongue and upper cheek regions. In addition, there are numerous other secreting glands producing saliva which keeps the lining tissues (mucosa) moist, lubricates ingested food and aids digestion.

The tonsils sit in tissue clefts on each side at the back of the throat. They are made of lymphoid tissue and play an important role in immunity in the first few years of life. Similar lymphoid tissue is found in the midline at the very top of the pharynx (adenoids) and across the tongue base forming a protective ring surrounding the entrance to the airway and gullet (Waldeyer’s ring). These structures are well positioned for exposure to inhaled and ingested substances and have deep crevices which increase their active surface area for producing antibodies to bacteria, viruses and other agents. They usually shrink after puberty.

The voice box (larynx) has three main functions – voice production, an airway to the lungs and protection of the airway when swallowing. The vocal cords are two muscle bands covered with a thin surface membrane which oscillates like the fronds of a sea anemone. Two opposing sets of muscles open and close the vocal cords in a controlled way breaking up the airflow exhaled from the lungs and giving vibratory energy which produces a basic sound. A change in the tension and length of the vocal cords causes a change in the vibration pattern and hence pitch the the sounds produced. The shorter length of the vocal cords in females is the main reason the average pitch of their voice is higher than a males. The tongue, lips, teeth and soft palate then modify these sound bites to form words, whilst resonance in the sinuses gives added volume. The airway is protected by a covering movement of the epiglottis, by inward movement of soft tissue above the vocal cords (false vocal folds) and by the vocal cords moving together (adduction). Any foreign material which gets through this multi-layer protection and passes through the vocal cords will enter the airway and induce a cough reflex. This is what occurs when something swallowed goes down “the wrong way”, and serves to expel the foreign material from the airway.