How do our Brains Control Swallowing?

The Parts of the Brain that Control Swallowing

The vagus and other cranial nerves involved in swallowing
Photo © A.D.A.M.

Believe it or not, swallowing is one of the most complicated tasks performed by the nervous system. It occurs in three sequential phases that require the carefully coordinated function of muscles in the mouth, pharynx, larynx, and esophagus -- all of which are under the control of cranial nerves.

In turn, cranial nerves are controlled by “processing centers” in the brain where information related to swallowing is processed.

These centers include areas located in the cerebral cortex, the medulla oblongata, and the cranial nerve nuclei.

Swallowing Centers

The voluntary initiation of swallowing takes place in special brain areas located in the precentral, posterior-inferior, and frontal- gyri. These structures send orders via axons that travel inside a nerve bundle called the corticobulbar tract, to a third swallowing center in the medulla.

The latter integrates these orders with information carried by several sensory nerves in the mouth, pharynx, and larynx, in order to deliver final orders to the muscles that carry out the swallowing reflex.

Sensory Nerves

Nerve signals originating in the mouth bring information to the brain about the food we are chewing. For instance, they "tell" the brain about the size, temperature, and texture of food. This information directs the efforts of the muscles of chewing which work together to chew the food, which changes it into a softer and more slippery food bolus that is suitable for swallowing.

As the swallowing reflex advances through its different phases, the nerves involved in swallowing trigger the reflexive closing of the larynx and the epiglottis, which prevents food and liquid particles from entering the lungs. Find out about aspiration pneumonia, which can happen if food enters the lungs due to weak swallowing muscles after a stroke.

Here are the sensory nerves involved in swallowing:

  • Trigeminal (cranial nerve V)
  • Facial (cranial nerve VII)
  • Glossopharyngeal (cranial nerve IX)
  • Vagus (cranial nerve X)

Cranial Nerve Nuclei

The muscles of swallowing are controlled by several cranial nerve nuclei. These are:

  • The nucleus ambiguous (of the vagus and glossopharyngeal nerves)
  • The dorsal motor nucleus (of the vagus nerve)
  • The hypoglossal nucleus (of the hypoglossal nerve)

How Is Swallowing Affected by Stroke?

As you can gather from the information written above, there are multiple areas of the central nervous system which, if affected by a stroke, could disrupt the ability to swallow. This is especially true for strokes of the medulla, as this is a relatively small area that contains multiple structures that are critical in carrying out the swallowing reflex. In fact, people with medullary strokes frequently require temporary or permanent feeding tube placement.


Richard Snell; Clinical Anatomy Fifth Edition; Little Brown and Company; 1995

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