normal swallow

There are 3 phases in swallowing: oral, pharyngeal, and oesophageal.

The oral phase is voluntary and starts when you push food with your tongue backwards into the throat.

The rest of the swallow is automatic or involuntary and involves the pahryngeal and oesophageal phases. There is an automatic process that begins at the back of the tongue and progressively travels down the throat (pharynx) and gullet (oesophagus) into the stomach. This process is a sequential wave of relaxation followed by contraction creating a travelling "squeeze" that pushes the food before it and down the food passage. Relaxation of the food passage muscles before the "squeeze" wave accommodates the food bolus which essentially travels down within the travelling wave of relaxed muscles. In the pharyngeal phase the larynx is lifted up (watch your adam's apple raise when you swallow) and is tucked up under the tongue base. At the same time the larynx is closed by the epiglottis acting like a lid to shut it off as the food passes by. The vocal cords are also brought together so that any liquid or food that gets past the epiglottis cannot go further into the airway. After the food goes past, the larynx lowers to it's normal position, the epiglottis tips up again and the vocal cords open so that you can breathe again. This phase is therefore quite quick.

The oesophageal phase is a continuation of the waves of relaxation and squeeze from the pharynx but is generally slower.