Saliva: Roles, Importance & Digestion of Food

Saliva is a fluid that mixes with food in the mouth during the process of chewing. It acts as a digestive juice that softens the food, allowing easy digestion. Saliva is mainly produced by the salivary glands, which are:

• Sub-Maxillary or Submandibular (Lower Jaw)
• Sub–Linguals (Below the Tongue)
• Parotids (Cheeks)

These glands are situated in the buccal cavity and secretes salivary juice. Saliva is an opalescent, dark, colourless fluid found in the mouths of vertebrates at all times. The human mouth excretes up to one to two litres of fluid every day.

Key Terms: Saliva, Electrolytes, Salivary Juice, Digestion, Buccal Cavity, Human Mouth, pH

---

Saliva Meaning

[Click Here for Sample Questions]

Saliva is a food fluid which blends with the food present in the mouth while chewing. 

• Saliva functions as a digestive juice and helps soften the food for easy digestion.
• Saliva is a dark, colourless, and opalescent fluid found in the mouth of all vertebrates and humans as well.
• Substances like proteins, mucus, air, amylase and mineral salts compose this fluid.
• Saliva is known to gather up food waste, white blood cells, and bacterial cells while circulating in the mouth cavity.
• The human mouth is known to excrete at least one to two litres of fluid every day.

Saliva Diagram

---

Components of Saliva

[Click Here for Sample Questions]

The contents of saliva are as followings –

• Calcium
• Potassium
• Magnesium
• Proteins
• Bicarbonate
• Phosphates and other electrolytes

These components thus interact in similar functions:

• Urea, phosphates, and bicarbonates provide saliva pH and stabilizing ability.
• Mucins and macromolecule proteins aid the purification, accumulation, help in binding oral microorganisms, and lead to plaque metabolism.
• Calcium, proteins, and phosphate function together for remineralization and demineralization by working as an anti–solubility factor.
• Immunoglobulins, proteins, and enzymes provide antibacterial activity.

---

Importance of Saliva

[Click Here for Sample Questions]

The elements of saliva work together to aid eating, speaking and keeping your mouth clean every day. As regarded by the American Dental Association (ADA), here are some of the importance of saliva:

• Wiping food debris
• Retaining strong teeth helps swallow and taste food
• Defending cavities
• Diagnosing health problems

---

Roles of Saliva

[Click Here for Sample Questions]

Here are some uses and roles of saliva –

• Saliva lubricates and moistens the food to make swallowing easier.
• Saliva produces salivary amylase (a digestive enzyme) that breaks down starch into sugar.
• Saliva allows food particles to stick together and be swallowed as a mass.

Read Also:

Dry Mouth

If a person lacks a supply of saliva, it is known as a dry mouth. It is advised to visit a doctor or a dentist regarding this issue.

Here are some Tips to keep your salivary gland safe –

• Drink enough water.
• Sugar–free gum should be chewed.
• Take a few bites of sugar–free candy.

If the person still has a dry mouth a doctor or dentist can suggest the usage of artificial saliva. Artificial saliva is a spray or a liquid that can be purchased. Artificial saliva keeps the mouth moist and comfortable.

Excessive Salivation

Excess saliva in mouth, or hypersalivation, occurs when a person’s one or more salivary glands are overactive or the person has difficulty swallowing.

• Too much saliva is usually not a cause of concern until it continues. 
• Excess saliva can be produced depending on the food you eat. 
• Excess saliva is usually dealt with by swallowing more saliva.
• The amount of saliva produced is usually determined by the taste buds on the tongue. 
• When we eat something sour or spicy, our taste buds react by producing more saliva. 
• Acidic food usually causes a lot more saliva production than sweet foods.

It is advisable to visit a doctor or a dentist for excess saliva. Excess saliva can be the outcome of a medical condition or illness or it could be a side effect of a drug.

Read More: Human Digestive System

---

What is the Role of Saliva in Digestion of Food?

[Click Here for Sample Questions]

The buccal cavity performs two important functions namely mastication of food and facilitation of swallowing.

• The tongue and teeth help the saliva masticate and mix up the food. 
• Mucus in saliva helps in the lubrication and adhesion of the masticated food particles into a bolus. 
• The bolus is then conveyed into the pharynx and then into the oesophagus by swallowing or deglutition.
• The saliva secreted into the oral cavity contains enzymes, salivary amylase, electrolytes, and lysozyme. 
• The chemical process of digestion is started in the oral cavity by the hydrolytic action of the carbohydrate-splitting enzyme, salivary amylase.

Read More: Tongue Diagram

---

Things to Remember

• Saliva is a fluid that mixes with food in the mouth during the process of chewing. It acts as a digestive juice that softens the food that allows for easier digestion.
• The contents of saliva are Calcium, Potassium, Magnesium, Proteins, Bicarbonate, Phosphates, and other electrolytes.
• Saliva produces salivary amylase (a digestive enzyme) that breaks down starch into sugar.
• Excess saliva occurs when a person’s one or more salivary glands are overactive or the person has difficulty swallowing.
• If a person lacks the supply of saliva, it is known as a dry mouth. It is advised to visit a doctor or a dentist regarding this issue.

Read More: