Composition and Functions of Saliva

  • Saliva is 99.5% water and contains electrolytes like sodium, potassium, calcium, magnesium, chloride, bicarbonate, and phosphate.
  • Mucus, antibacterial compounds, and enzymes such as α-amylase and lingual lipase are present in saliva.
  • Saliva aids in digestion, maintains oral hygiene, prevents tooth decay, and acts as a lubricant for eating, swallowing, and speaking.

Salivary Output and its Importance

  • A healthy person produces around 1500ml of saliva per day.
  • The submandibular gland produces the highest amount of saliva (70-75%), followed by the parotid gland (20-25%).
  • Reduced salivary function increases the risk of dental caries, gum disease, and other oral problems.

Saliva as a Lubricant

  • Saliva coats the oral mucosa, protecting it from trauma during eating, swallowing, and speaking.
  • Reduced saliva (xerostomia) can cause mouth soreness and difficulties in swallowing and speaking.
  • Adequate saliva production is essential for oral comfort and function.

Saliva and Digestion

  • Saliva moistens food and helps create a food bolus.
  • Saliva contains enzymes like amylase and lipase that break down starch and fats.
  • About 30% of starch digestion occurs in the mouth cavity.
  • Salivary lipase is particularly important for newborn infants.

Other Aspects of Saliva

  • Saliva production is influenced by the nervous system, with sympathetic stimulation leading to thicker saliva and parasympathetic stimulation leading to more fluid-like saliva.
  • Saliva can be pharmacologically stimulated or suppressed.
  • Saliva has cultural and behavioral significance, such as spitting being considered rude in many cultures.
  • Saliva has been studied for its potential diagnostic applications and its role in oral health, as well as its association with the 2019 novel coronavirus.

Saliva Data Sources

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