What are Salivary Glands and their Functions?

Salivary glands are present in the mouth and secrete saliva that helps in the digestion of food. Of what saliva is made? What is the function of saliva? Let us study through this article?
Created On: Feb 20, 2020 17:03 IST
Modified On: Feb 20, 2020 17:03 IST
Salivary Glands: Location, Function and Types
Salivary Glands: Location, Function and Types

Let us tell you that saliva is 98% of water but contains electrolytes, antibacterial compounds, mucus, enzymes, etc. 

Salivary Glands are a group of organs present in our mouth that secretes saliva. It is found in mammals only. It is an exocrine gland that secretes substances outside the body or within a body cavity. Saliva contains various chemicals with water including mucus, salts, antibacterial substances, enzymes and chemicals that control the pH in the mouth.

Do you know that the quantity of saliva increases when we taste, smell, or even think of food? It decreases when we go to sleep. Basically, saliva is a watery substance and is a part of the Digestive System. Salivary Glands secrete 1 to 1.5 litres of saliva in 24 hours. In fact, over 98% of saliva is water. It keeps the mouth moist and clean, facilitates chewing, swallowing and helps in the digestion process. 

Functions of Salivary Gland
Saliva is a mixture of water, mucus, antibacterial substance, and digestive enzymes. Therefore, saliva has many uses. One of the digestive enzyme alpha-amylase helps to break down the starch present in our food into a simpler one like glucose and maltose. Whenever we chew, we activate these glands to secrete an enzyme to breakdown the food. Saliva has lubricating properties. It protects the inside cavity of our mouth, teeth, and throats as we begin to swallow the food bolus. It also cleanses the mouth after the meal and dissolves it into chemicals that we perceive as taste.

Types of Salivary Gland

Types of major salivary glands

Source: www.headandneckcancerguide.org.com

According to the size and functional importance, it is of two types: minor and major salivary glands.

1. Minor salivary gland
The mucosa of the mouth, lips, tongue, and palate is filled with many small salivary glands that moisten these surfaces. Do you know that around 800 or 1000 minor salivary glands are located throughout the mouth? They secrete saliva directly into the mouth.

Ductless Glands present in the Human Body
2. Major salivary glands
There are three pairs of glands through which most of the saliva is secreted and symmetrically located on both sides of the jaw. They secrete saliva through ducts. These glands are parotid, submandibular and sublingual.

Parotid Gland
Parotid glands are the largest salivary gland. Each gland is approximately 6 cm long and 3-4 cm wide and can weigh up to 30 grams. They are located within each of our cheeks. In our oral cavity, they are responsible for the secretion of about 20% of saliva. This saliva is known as serous i.e. more liquid and fluid. It helps in the first phase of the digestion of food, facilitate mastication "chewing". These glands secrete a protein-rich fluid which is a suspension of alpha-amylase enzyme. Do you know why alcohol abuse is directly related to the lack of saliva? Because intake of alcohol or some drugs can affect the sympathetic nervous system and produces vasoconstriction of the parotid gland and reduces the secretion of saliva.

Submandibular gland
These glands are located beneath the lower jaw, outside the oral cavity. This is the movable part of our jaw. It is the second-largest salivary gland and produces approx. 65-70% of saliva. It is a mixture of serous and mucous glands and released through submandibular ducts. Its saliva is more viscous as compared to the secretion of the parotid gland.

Sublingual gland
It is the smallest of the major salivary glands. They are located under the tongue. Approximately 5% of the saliva comes from these glands. The saliva that comes out is mostly mucus, having a viscous texture and flows into the mouth through sublingual ducts. Sometimes, sialoliths also termed as salivary calculi, or salivary stones form in the ducts of salivary glands which block the flow of saliva and cause pain, swelling in the affected gland. Mostly, salivary stones affect submandibular glands and sometimes parotid too.

From the above article, we have learned about salivary glands, its types, functions and where they are located.

Human Digestive System

 

Source: www.headandneckcancerguide.org.com

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