Which type of muscle is used when swallowing food?

January 1, 2026 •

4 min read

The act of swallowing, or deglutition, is a complex neuromuscular process that involves the precise coordination of over 50 pairs of muscles and numerous nerves. The answer to which type of muscle is used when swallowing food is not singular, as the process relies on both voluntary skeletal muscle and involuntary smooth muscle.

Quick Summary

Swallowing utilizes a combination of skeletal and smooth muscle. The initial oral phase is voluntary, involving the tongue and jaw. Once triggered, the pharyngeal and esophageal phases are involuntary, using muscles in the throat and esophagus to propel the food bolus toward the stomach via peristalsis.

Key Points

Dual Muscle System: Swallowing is not controlled by a single type of muscle but involves both voluntary skeletal muscle and involuntary smooth muscle.
Voluntary Oral Phase: The initial stage uses skeletal muscles like the tongue and jaw to manipulate and push food into a bolus.
Involuntary Pharyngeal and Esophageal Phases: After the initial push, the process becomes a reflex managed by the brainstem's swallowing center.
Muscle Composition in the Esophagus: The upper third of the esophagus is skeletal muscle, the middle third is a mix, and the lower third is exclusively smooth muscle.
Peristalsis: In the esophagus, food is moved toward the stomach by wave-like, involuntary contractions known as peristalsis, driven by smooth muscle.
Airway Protection: Specialized skeletal muscles in the pharynx and larynx elevate the larynx and close the epiglottis to prevent food from entering the airway.

The Dual Nature of Swallowing Muscles

Swallowing is a multi-stage process that seamlessly transitions from conscious, voluntary control to an automatic, involuntary reflex. This transition is made possible by the different types of muscle tissue involved. The oral phase, for example, is controlled by voluntary skeletal muscles, while the later stages in the pharynx and esophagus are managed by both skeletal and smooth muscles.

The Oral Phase: Voluntary Control

This initial stage is where we consciously prepare and move food. The action is entirely voluntary and is managed by the skeletal muscles of the oral cavity. Here, food is chewed and mixed with saliva to form a soft mass called a bolus.

Key skeletal muscles of the oral phase:

Tongue muscles: A group of extrinsic and intrinsic muscles, such as the genioglossus and styloglossus, manipulate the food and push the bolus towards the back of the mouth.
Muscles of mastication: Muscles like the masseter and temporalis are responsible for chewing and breaking down food.

When the bolus reaches the back of the tongue, it stimulates touch receptors, triggering the involuntary pharyngeal phase.

The Pharyngeal Phase: Triggering the Reflex

Once the oral phase is complete, the swallowing reflex is initiated by a swallowing center in the brainstem, making this and the subsequent phase entirely involuntary. This rapid stage involves a complex sequence of muscle contractions to move the bolus safely past the airway and into the esophagus. The muscles in this region are primarily skeletal, but they operate under reflexive control.

Critical actions in the pharyngeal phase:

Airway protection: The soft palate elevates to seal off the nasal cavity, and the larynx rises while the epiglottis closes over the trachea to prevent food from entering the windpipe. The intrinsic laryngeal muscles, all skeletal, are essential for this action.
Bolus propulsion: The pharyngeal constrictor muscles—the superior, middle, and inferior constrictors—contract in a rapid, peristaltic sequence to propel the bolus down the pharynx toward the esophagus.

The Esophageal Phase: Automatic Propulsion

Following the pharyngeal phase, the bolus enters the esophagus, a muscular tube connecting the throat to the stomach. This phase is also involuntary and relies on a combination of muscle types.

The transition from skeletal to smooth muscle:

Upper esophagus: The upper third of the esophagus is composed of striated, or skeletal, muscle.
Middle esophagus: The middle third contains a mixture of both skeletal and smooth muscle.
Lower esophagus: The lower third is exclusively smooth muscle.

This gradual transition allows for a seamless handover from the forceful, rapid contractions of the skeletal muscle in the pharynx to the slower, wave-like contractions of the smooth muscle in the esophagus, a process known as peristalsis. The lower esophageal sphincter, composed of smooth muscle, then relaxes to allow the bolus to enter the stomach, preventing acid reflux afterward.

Comparison of Muscle Roles in Swallowing


Feature	Oral Phase (Voluntary)	Pharyngeal & Esophageal Phases (Involuntary)
Muscle Type	Primarily skeletal (striated) muscle.	Mixed; skeletal muscle in the pharynx and upper esophagus, transitioning to smooth muscle in the lower esophagus.
Initiation	Consciously initiated; under voluntary control.	Reflexively triggered by the presence of a bolus in the pharynx; controlled by the brainstem swallowing center.
Primary Function	Manipulates and prepares food into a bolus; initiates the swallow.	Propels the bolus down the throat and esophagus to the stomach via peristalsis; protects the airway.
Key Muscles	Tongue muscles (e.g., genioglossus), muscles of mastication.	Pharyngeal constrictors, laryngeal muscles, smooth muscle layers of the esophagus.

The Orchestration of the Swallowing Reflex

Though we rarely think about it, the act of swallowing is a marvel of biological coordination. The brainstem's swallowing center acts as the command hub, receiving sensory input about the bolus and generating a precisely timed motor output to the relevant muscles. This involves multiple cranial nerves, including the trigeminal (CN V), facial (CN VII), glossopharyngeal (CN IX), and vagus (CN X) nerves, which are vital for both the sensory input and motor output. The intricate sequence ensures that the airway is sealed off just as the food is propelled into the esophagus, preventing aspiration and choking.

Conclusion: A Symphony of Muscle Types

In conclusion, swallowing food requires a dynamic partnership between different types of muscle. The voluntary skeletal muscles of the tongue and jaw start the process, but as the food moves into the pharynx, the control shifts to an involuntary reflex involving both fast-acting skeletal muscle and the slower, rhythmic smooth muscle of the esophagus. This elegant coordination of voluntary and involuntary actions ensures that food is safely and efficiently transported from the mouth to the stomach every time we eat. For a deeper dive into the specific anatomy and physiology, the National Institutes of Health (NIH) is a great resource.

Frequently Asked Questions

Skeletal muscle, found in the tongue and upper esophagus, is under voluntary control during the initial stage of swallowing. Smooth muscle, which is involuntary, takes over in the lower esophagus to propel food downward through peristalsis.

While gravity can assist, the process is primarily driven by muscle contractions, a process called peristalsis. You can swallow food even when standing on your head, proving that muscle action is the main force.

If muscles or nerves involved in swallowing fail, it can lead to dysphagia, or difficulty swallowing. This can cause discomfort, lead to aspiration of food into the airway, and in some cases, severe complications.

Swallowing is controlled by a complex network of cranial nerves, including the trigeminal (V), facial (VII), glossopharyngeal (IX), and vagus (X) nerves, all coordinated by a swallowing center in the brainstem.

The epiglottis, the flap that covers the trachea during swallowing, is moved by skeletal muscle, allowing for voluntary control and precise timing to protect the airway.

Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract. It begins in the esophagus, specifically the lower two-thirds where smooth muscle is dominant, and continues through the stomach and intestines.

There are three main phases of swallowing: the oral phase (voluntary), the pharyngeal phase (involuntary), and the esophageal phase (involuntary).