Swallowing Reflex, Phases and Overview of Neural Control, Animation.

Summary

Swallowing, or deglutition, is a complex process that involves the coordination of over twenty muscles and multiple brain regions. It consists of three phases: the voluntary oral phase where food is chewed and pushed to the throat; the involuntary pharyngeal phase, where food is safely moved through the throat with actions to protect the airway; and the esophageal phase, where the food is propelled down the esophagus by peristalsis. This intricate process requires precise coordination with breathing to prevent choking or aspiration, highlighting its importance for safe swallowing and overall health.

Takeaways

• 😀 Swallowing, or deglutition, is the process by which food moves from the mouth through the pharynx into the esophagus.
• 😀 Swallowing may seem simple, but it involves complex coordination between various muscles and processes.
• 😀 The pharynx serves as the shared entrance for both swallowing and breathing, requiring precise coordination to avoid choking or aspiration.
• 😀 Over 20 muscles in the mouth, throat, and esophagus are involved in swallowing, controlled by multiple brain regions and cranial nerves.
• 😀 Swallowing occurs in three phases: Oral (voluntary), Pharyngeal (involuntary), and Esophageal (involuntary).
• 😀 During the Oral phase, food is chewed and mixed with saliva, forming a bolus that is pushed to the back of the throat by the tongue.
• 😀 The Pharyngeal phase begins when tactile receptors in the oropharynx are triggered by the food bolus, starting the swallowing reflex.
• 😀 Several protective actions occur during the Pharyngeal phase: the tongue blocks the mouth, the soft palate seals off the nasal cavity, and the vocal folds close to protect the airway.
• 😀 The epiglottis flips over during the Pharyngeal phase to cover the trachea and prevent food or drink from entering the lungs.
• 😀 In the Esophageal phase, the food bolus is propelled down the esophagus through peristalsis, a wave-like muscle contraction.

Q & A

What is the process of swallowing, also known as deglutition?

Swallowing, or deglutition, is the process by which food passes from the mouth, through the pharynx, and into the esophagus.

Why is swallowing considered a complex action despite seeming simple?

Swallowing is complex because it requires precise coordination with breathing, as both processes share the same entrance, the pharynx. A failure in coordination can lead to choking or pulmonary aspiration.

How many muscles are involved in swallowing, and where are they located?

Swallowing involves over twenty muscles located in the mouth, throat, and esophagus.

Which areas of the brain control the muscles involved in swallowing?

The muscles involved in swallowing are controlled by several cortical areas and by the swallowing centers in the brainstem.

What role do cranial nerves play in swallowing?

The brain communicates with the muscles involved in swallowing through several cranial nerves.

What are the three phases of swallowing?

The three phases of swallowing are the oral (buccal) phase, the pharyngeal phase, and the esophageal phase.

What happens during the oral or buccal phase of swallowing?

In the oral phase, the food is moistened with saliva, chewed, and formed into a bolus. The tongue then pushes the bolus to the back of the throat. This process is under voluntary neural control.

What occurs during the pharyngeal phase of swallowing?

The pharyngeal phase begins when tactile receptors in the oropharynx are stimulated by the food bolus. The swallow reflex is initiated, and the tongue blocks the oral cavity, the soft palate blocks the nasal cavity, and the vocal folds close to protect the airway.

Why is the closure of the vocal folds important during swallowing?

The closure of the vocal folds is crucial because it protects the airway, preventing food or drink from entering the lungs, which could be life-threatening.

What happens during the esophageal phase of swallowing?

During the esophageal phase, the food bolus is propelled down the esophagus by peristalsis, a wave of muscular contraction. The larynx also moves back to its original position.