Salivary Glands

Salivary glands are exocrine glands located in the mouth to aid in digestion. Their secretions play a crucial role in digestion, protection, lubrication, and oral health. The secretion of the salivary gland comprises enzymes, electrolytes, mucus and antibodies. Let’s learn more about the secretions of salivary glands in detail.

What Are Salivary Glands?

Salivary glands are exocrine glands. This means they release their secretions into ducts on the external or internal body surfaces instead of directly into the bloodstream. Hence, salivary glands secrete their secretion (saliva) into the mouth cavity.

Saliva may seem like a simple “spit.” But it’s a complex fluid filled with enzymes, water, mucus, electrolytes and antibodies. Together, these components help us taste, chew, swallow, and digest food.

Alt text: Major Salivary Glands

Location of Salivary Glands

You’ll find salivary glands scattered around your mouth and throat. Some are large, and some are tiny.

The major salivary glands are paired and located outside the oral cavity. They open into the mouth through ducts.
The minor salivary glands are much smaller and more numerous. They are spread across the lips, tongue, inner cheeks, and palate.

So, whether you are smiling, speaking, or eating, salivary glands are working nearby.

Function of Salivary Glands

The role of salivary glands goes far beyond just “wetting” your food. Without saliva, daily life would become extremely uncomfortable. Hence, their main functions include:

Lubrication: Saliva moistens food, making it easier to chew and swallow.
Digestion: It contains the enzyme amylase, which starts breaking down starch into sugars.
Taste: Saliva dissolves food chemicals so taste buds can sense them.
Protection: It keeps the mouth clean, controls bacteria, and protects teeth from decay.
Speech: A moist mouth helps with clear pronunciation.

Alt text: Functions of the Salivary Gland

Salivary Secretions

An adult produces between 0.5 to 1.5 litres of saliva every day. Among these, the saliva is about 99% water. But the remaining 1% comprises the main components, listed as follows:

Component	Function
Enzymes	Amylase breaks down starch Lipase breaks down fat
Mucus	Adds thickness to saliva and helps with swallowing
Electrolytes	Like sodium, potassium, and chloride, which keep the mouth balanced
Antibodies	Especially IgA, which defends against microbes

Types of Salivary Glands

There are three major salivary glands and many minor ones. Each type contributes differently to saliva production.

1. Parotid Glands

Largest of the major salivary glands
Found just in front of the ears, stretching down to the jawline.
Mainly produces serous (watery) saliva rich in amylase.

2. Submandibular Glands

Found beneath the lower jaw, at the back of the mouth.
Produce both serous and mucous secretions.
Supply the majority of resting saliva.

3. Sublingual Glands

Smallest major salivary glands.
Located under the tongue.
Mainly secretes mucous saliva, which is thick and helps with lubrication.

4. Minor Salivary Glands

Hundreds of small glands are spread around the lips, cheeks, tongue, and palate.
Constantly secrete saliva in small amounts to keep the mouth moist.

Salivary Glands at a Glance

Gland Type	Location	Type of Secretion	Main Function
Parotid	In front of the ears	Watery and enzyme-rich (serous)	Starts starch digestion
Submandibular	Beneath the lower jaw	Mixed: serous + mucous	Produces the most saliva
Sublingual	Under the tongue	Mostly mucous	Lubrication
Minor salivary glands	Spread across the mouth & throat	Mostly mucous	Keeps the mouth moist

Why Are They Important?

Imagine eating dry bread without saliva. It would be nearly impossible to chew and swallow comfortably. Saliva also ensures you can taste flavours properly and helps prevent tooth decay.

In medical practice, problems with salivary glands can signal disease. For example:

Swollen parotid glands may point to mumps.
Dry mouth can be caused by reduced saliva due to medications or conditions like Sjögren’s syndrome.
Stones or blockages in ducts can lead to painful swelling.

This is why doctors often check the salivary glands during routine examinations.

Final Thoughts

Salivary glands may be small, but they play a huge role in everyday life. These exocrine glands release their secretions into the mouth cavity. There are three major salivary glands, the parotid, submandibular and sublingual glands. They are located within the mouth but in different regions. With a primary role in digestion, they are essential for lubrication, taste, protection, and speech.

Frequently Asked Questions

Q1. What are the symptoms of a blocked salivary gland?

Often due to infection a salivary gland may get blocked. It can lead to various symptoms. The common ones are swelling and pain under the jaw or near the ear. This may worsen when one eats or drinks. Difficulty in swallowing and dry mouth are also observed.

Q2. Can salivary gland tumours be cancerous?

Rarely. Most salivary gland tumours are found to occur in the parotid gland. Most of them are non-cancerous. On average, one in five is found to be cancerous.