Dysphagia – Symptoms and Causes

Question 1 Describe different phases of deglutition and their regulation.

Answer:

Deglutition:

• Deglutition is process by which chewed food is emptied from the mouth into the stomach.

Stages/Phases of Deglutition:

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1. Deglutition Oral phase:

• Deglutition Oral phase is voluntary stage.
• After mastication chewed food, moistened and lubricated by saliva, is rolled into bolus.
• The bolus is placed over posterodorsal surface of the tongue.
• At this, the anterior part of tongue is retracted and depressed while the posterior part is elevated and retracted.
• This pushes bolus into the pharynx.

2. Deglutition Pharyngeal stage:

• Deglutition Pharyngeal stage shows involuntary, complex, closely coordinated movements in the pharynx that pushes the bolus into the oesophagus.
• Deglutition Pharyngeal stage lasts for 1-2 seconds.
  • Soft palate is elevated and thrown against posterior pharyngeal wall closing the posterior nares.
    • This prevents the reflux of food into the nasal cavities.
  • Larynx rises with elevation of hyoid bone vocal cords are approximated and breathing is arrested.
    • This prevents entry of food into the larynx.
  • Palatopharyngeal folds approximate to shut off the oral cavity.
    • This prevents the entry of bolus back into the oral cavity.
  • The upward movement of the larynx stretches to opening of the oesophagus.
    • Due to contraction of pharyngeal muscles, peristaltic contractions start in the pharynx.
    • Elevation of larynx also lifts the glottis away from the food passage.
    • Due to all these, the bolus moves easily into the esophagus.

3. Deglutition Esophageal stage:

• This stage for liquid food lasts for 1-2 seconds and for dry food it lasts for 10 seconds.
• Deglutition Esophageal stage is also involuntary stage.
• When bolus reaches the oesophagus, the peristaltic waves are intiated, which propel the bolus into the stomach.

Types of peristaltic contractions:

1. Primary peristaltic contractions:
   • Primary peristaltic contractions starts as soon as bolus reaches the upper part of oesophagus.
   • As a result of this contraction, a pressure develops to propel the bolus.
   • Initially this pressure is negative which immediately becomes positive.
2. Secondary peristaltic contractions:
   • Due to the distention of upper esophagus by the bolus, secondary peristaltic contractions occurs.
   • These contractions passes down, and propels the bolus into stomach.

Deglutition Regulation:

Entry of bolus into the oropharyngeal region.
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Stimulation of receptors present in the.

1. Mucous membrane covering mouth and pharynx
2. Posterior pharyngeal wall.
3. Soft palate and
4. Epiglottis.

Impulses from these receptors pass via glossopharyngeal nerve to the deglutition center present at the floor of the fourth ventricle in medulla.
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Efferent fibers pass through motor fibers of V, VII, IX, X and XII nerves to the pharyngeal musculature and tongue.
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This causes.

1. Initiation of pharyngeal stage.
2. Upward movement of soft palate to close nasopharynx.
3. Upward movement of larynx to close respiratory passage.
4. Entry of bolus into oesophagus.

Question 2. What are the stages of deglutition? Describe them in detail with a note on dysphagia.
Answer:

Dysphagia:

• Dysphagia is the condition of difficulty in swallowing.

Dysphagia Causes:

• Mechanical obstruction of oesophagus.
• Decreased movement of oesophagus.
• Muscular disorders.