What Is Mucus?
With its sticky persistence and its green grossness, it is no wonder that mucus has a bad reputation. In spite of its less-than-pleasant qualities, however, it is actually a remarkable substance that is largely responsible for the health of the respiratory system. It prevents sensitive tissues from drying out, traps harmful foreign invaders that threaten to infect the body, and wages war on existing infections.
Mucus is a slick substance secreted by the mucous membranes that line many of the body’s inner surfaces, such as the lungs and the nasal passages. It consists of proteins, antimicrobial enzymes, antibodies, and salt. While the average person produces around 4.25 cups (approximately one liter) of the secretion each day, it is normally fairly thin and unnoticeable. It is usually only when the body becomes infected that it takes on the nostril-plugging, cough-rousing consistency that sends many running to the doctor for relief.
The mucus has three primary functions: keeping bodily tissues moist, trapping foreign bodies to prevent infection, and attacking the causes of existing infections. Its moisturizing properties are important to the health and comfort of the body’s many mucous membranes. Once secreted, it forms a kind of shield of dampness over these surfaces. Without this protective covering, the membranes would quickly become dried out and irritated.
While the stickiness of mucus may be disagreeable, it is this very property that allows the substance to perform an important protective duty. It traps foreign bodies like bacteria in its gooey clutches before they can set up shop in the body and cause an infection. Once these bodies have been trapped, they are eliminated by the antimicrobial enzymes contained within the substance.
Despite the body’s best efforts to nip infection in the bud, sometimes viruses and bacteria manage to invade and cause illness. When this happens, the mucus plays yet another role. Its antibodies seek out the infecting bodies and then kill them.
It is when the body has been infected that the mucus takes on the qualities with which it is generally associated: green color, thick consistency, and seemingly endless abundance. This green hue is caused by a green enzyme contained in the antibodies. When the body is infected, these antibodies are dispatched to the mucus in larger quantities than usual, thus giving it a noticeable coloration.
Thickness and increased production are also defensive features which enhance the mucus’s ability to trap and neutralize infection. While in the throes of a drippy cold or stuffy sinus infection, it can be tempting to sideline respiratory secretions with a decongestant or antihistamine. Before cursing the sticky stuff, however, remember that it plays an important role in making — and keeping — the body healthy.
Written by M.C. Huguelet
