Match the phase of swallowing with the correct events:
Initiated by stimulation of tactile receptors in the oropharynx
Peristalsis moves food bolus onward
The lower esophageal sphincter relaxes
Begins with elevation of the soft palate
Food bolus forced into the oropharynx
The upper esophageal sphincter relaxes
F
The Correct Answer and Explanation is:
Here is the correct matching of each swallowing event with its appropriate phase of swallowing:
1. Oral Phase (Voluntary)
- Food bolus forced into the oropharynx
2. Pharyngeal Phase (Involuntary)
- Initiated by stimulation of tactile receptors in the oropharynx
- Begins with elevation of the soft palate
3. Esophageal Phase (Involuntary)
- Peristalsis moves food bolus onward
- The lower esophageal sphincter relaxes
- The upper esophageal sphincter relaxes
300-Word Explanation:
Swallowing, also known as deglutition, is a complex process that involves the coordinated activity of the mouth, pharynx, and esophagus to transport food from the oral cavity to the stomach. This process is typically divided into three phases: oral, pharyngeal, and esophageal.
The oral phase is voluntary and begins when the tongue pushes the chewed and moistened food, called the bolus, toward the back of the mouth. The food bolus is forced into the oropharynx during this stage, and the act of pushing initiates the next phase.
The pharyngeal phase is involuntary and is triggered by stimulation of tactile receptors in the oropharynx when the bolus touches the back of the throat. This triggers a reflex involving the brainstem. During this phase, the soft palate elevates to seal off the nasopharynx and prevent food from entering the nasal cavity. Simultaneously, the epiglottis covers the trachea to prevent aspiration.
Following this is the esophageal phase, which is also involuntary. It begins when the upper esophageal sphincter relaxes, allowing the bolus to enter the esophagus. Once inside the esophagus, peristalsis (a series of coordinated, wave-like muscle contractions) propels the bolus downward. Near the end of this phase, the lower esophageal sphincter relaxes, allowing the bolus to enter the stomach.
Each phase is crucial for safe and effective swallowing. Impairments in any phase can lead to dysphagia (difficulty swallowing) or aspiration, particularly in individuals with neurological or muscular disorders. Understanding the swallowing phases helps nurses and clinicians assess swallowing function and manage associated risks in patients.