Pharynx and Oesophagus - (Swallowing and Peristalsis):

The bolus is swallowed and then pushed down by the movement called peristalsis.

Steps in swallowing:

During swallowing the bolus is pushed to the back of the mouth by the tongue. The soft palate moves upward and to the rear to close the opening of the nasal cavity. When swallowed, the bolus goes to the pharynx, which makes special adaptations to prevent choking or aspiration when food is swallowed. When the larynx (the top of the trachea) moves upward, it forces the epiglottis (a flap of cartilage) into a more or less horizontal position thus closing the glottis i.e., opening of the windpipe (trachea) The beginning of the swallowing action is voluntary, but once the food reaches the back of the mouth, swallowing becomes automatic.

After being swallowed, the food enters the tube called the oesophagus, which connects the pharynx to the stomach. Neither the pharynx nor the oesophagus contributes to digestion and the previous digestive actions of saliva continue.

Steps in Peristalsis:

Peristalsis moves the food from the oral cavity to the rectum. It is defined as the rhythmic sequence of waves of contraction in the smooth muscles of the walls of the alimentary canal, thus squeezing the food down along the alimentary canal.