What is mucus and where does it come from?

What is mucus and where does it come from?

When you’re feeling ill with a cold, sore throat or flu, or experiencing an allergic reaction, you will typically encounter a number of symptoms. One of the nastier symptoms of these conditions can manifest itself as a  feeling that your nose and throat are blocked and that a substance is stuck in these areas.

In fact, what you’re experiencing is a build of a mucus, and while it may seem unpleasant and something you’d rather avoid, it is actually present in the body to offer protection and keep natural processes running as normal. It remains constantly within your system, but it’s likely that you will only recognise it when you’re unwell or experiencing an allergic reaction and, as a result, your body has begun to produce more mucus.

In an effort to explain the importance of mucus, this guide explains exactly what it is, where it comes from and how it contributes to protecting the body

What is mucus?

Also commonly known as snot, mucus is a slimy, sticky substance that works as a lining in your nose, mouth, throat, lungs and sinuses. Often compared to phlegm, the two share a similar appearance and both function in a similar way. However, they are different, with mucus being thinner and coming from the sinuses and phlegm being thicker, forming in your throat and lungs[1].

Where does mucus come from?

There are two primary types of tissue lining the mouth, nose, sinuses and airways: ciliated cells that are covered in hair and secretory cells that release mucus. Small amounts of mucus are always likely to form, but when irritants are detected in the airways, mucus is produced in larger amounts, causing the congested feeling that happens during viral throat infections, colds and allergic reactions. As both collated and secretory cells are located in different areas of the body, mucus can be produced in a broad selection of locations.

What is the purpose of mucus in human defence systems?

The main purpose of mucus is to protect the body’s respiratory system by filtering out potentially harmful substances and maintaining sufficient lubrication. Breathing in causes any number of substances to enter the body – whether that’s dust, allergens, harmful bacteria or other elements that could potentially impact the body. Mucus helps to absorb these substances, and when the mucus naturally comes out of the body, it brings the substances with it to remove them[1].

How does mucus protect the body?

As mucus actively stops unwanted substances, clings on to them and removes them from the body, it prevents them from moving further into the body and causing potentially serious harm. In some cases, this could have a significant impact on protecting the body. The lungs, for example, are exposed to many substances that enter the body including bacteria. But through the presence of mucus, lungs are protected and any potentially harmful substances will be stopped before they can reach the lungs.

Not only that, but mucus also contains protective forms of protein that can kill and disable the harmful properties of germs and bacteria. This means that even if they were able to pass through the mucus to sensitive parts of the body, they are typically ineffective and unlikely to cause serious harm.

However, in some cases, the body can produce too much mucus, leading to a build up that can make you feel even worse. In this scenario, while the presence of mucus is positive and means that your body is correctly responding to an unwanted substance in your body, you may want to consider using throat lozenges to reduce the level of mucus in your system.

Alongside the action of protecting the body from external agents, mucus also provides lubrication to ensure that natural processes happen correctly and prevent the individual from choking. In simple terms, mucus is present throughout the body, and without it, food and other substances would struggle to move across the digestive system and other processes wouldn’t happen as smoothly[1].


[1] https://www.nhs.uk/conditions/catarrh/