Stages of deglutition: oral, pharyngeal and oesophageal

STAGES OF DEGLUTITION

The process of swallowing is known as deglutition.

Oral stage

Pharyngeal stage:

Oesophageal stage

This is the only voluntary stage in the act of swallowing.

Mastication of food making it into a bolus fit to be swallowed

- Masseter

- Temporalis

- Pterygoids

- They are innervated by the mandibular division of the trigeminal nerve.

- The tongue is innervated by the hypoglossal nerve.

- The facial nerve innervates the buccinator and orbicularis oris.

Is involuntary and is very complex. It passes the masticated food through the oropharynx, through the cricopharynx into the upper oesophagus.

- Soft palate muscles

- Pharyngeal muscles

- Cricopharyngeal muscle

- The muscles of the soft palate, which is innervated by the fifth, seventh, ninth, and twelfth cranial nerves.

- The pharyngeal muscles conduct food through the cricopharynx, innervated by the ninth and tenth cranial nerves.

- The pharyngeal muscles also play a vital role in pushing food through the cricopharynx.

This stage is again involuntary. It propels the food bolus down the oesophagus. During swallowing, peristaltic waves pass down the oesophagus with waves of positive pressure reaching.

This phase is dependent on the peristalsis of the oesophageal musculature.

This phase is mediated by the 10th and sympathetic nerves.

When fluid is ingested, it can project from the pharynx to the gastric junction of the esophagus in approximately 1 second (when the subject is standing). This occurs long before the peristaltic wave. Therefore, it should be taken into account that this fact causes burns due to the ingestion of corrosive fluids more in the distal end of the esophagus.

Neurological disorders affecting the pharynx impair swallowing by altering motor and / or sensory functions in the oral and pharyngeal stages.

In patients with facial palsy the buccinator and orbicularis oris are paralyzed causing drooling on that side of the mouth.