Introduction
Man has always been plagued by the mucus accompanied by the common cold and winter seasons. The mucus is produced by the respiratory tract (airways) as a defensive mechanism during certain sicknesses. Mucus has several names, like the snot, phlegm, or sticky goo from the nose during a cold. Though the body recovers from sickness like a cold within a week, the phlegm remains much longer. It acts as an interface between the human body and the environment. People are never a fan of mucus. However, it is much more than a running nose. The human body constantly produces mucus, which plays a principal role in safeguarding the body. The production of mucus and coughing up are the natural defensive mechanism of the lungs to do away with the infectious microorganisms that enter the body through the respiratory route.
What Is Mucus?
Mucus is a safeguarding substance secreted and lining the multiple moist surfaces of the body like the mouth, airways, throat, lungs, and sinuses. The mucus acts as a filter in the nose and prevents the entry of unwanted materials and microbes into the body. It acts like flypaper; anything a person breathes, dust particles, microorganisms, and allergens, gets stuck onto the mucus.
Mucus is composed of several constituents, with the major component being a substance called mucin. The mucin serves multiple functions depending upon its location. For example, it can be a lubricant, selective barrier, or material preventing microbes' movement. In a normal healthy individual, the structure and functioning of the mucin will be normal, but when it is altered, it results in diseases.
How Does the Mucus Work?
Human beings inhale thousands of bacteria through their nose unknowingly. The microbes land on the mucous-lined membranes of the lungs and get trapped there. Cilia line the mucous membranes of the lungs; they are little hair-like projections that move and push the mucus along with the trapped dust, particles, allergens, bacteria, and viruses up through the airways out of the lungs. The body produces a large amount of mucus which is mostly watery. It contains sugars, special proteins, and substances that can help control infections. People are usually unaware of the flow of mucus through their bodies. However, mucous becomes prominent when people get sick. Examples of the intervention of the pathogens by the presence of mucus are
-
Pseudomonas Aeruginosa:
It is a bacteria that lives in human lungs and is harmless in healthy individuals. However, in disease conditions like cystic fibrosis (excess mucous production from the lungs), the bacteria will stick to each other and form groups known as biofilms. Forming biofilms makes the organisms more virulent, increasing the chances of infection.
The MUC5AC (mucin 5AC, oligomeric mucus/ gel-forming), a type of mucin in the lungs, prevents biofilm formation by the bacteria. Opposed to the conventional mechanism of trapping the bacteria, the MUC5AC increases the motility of the bacteria, and moving bacteria are less likely to get attached to the surface. Thus, preventing the chances of infection.
-
Candida Albicans:
Fungi causing yeast infections. Candida albicans live in the gut and mouth of 80 % of adults without causing any disease. However, the Candida species becomes active in the presence of another infection that reduces immunity or causes immunosuppression. It forms biofilms or hyphae that invade the human cells resulting in candidiasis. The presence of MUC5AC mucin will prevent biofilm and hyphae formation by a mechanism similar to the one seen in Pseudomonas aeruginosa and decreases the organism's virulence.
What Is the Diagnostic Potential of Mucus?
The mucus plays a protective function in the body when its texture, color, and quantity are normal. However, at times of sickness, the mucous produced will be atypical. An ill person produces abnormal mucus, manifested as an alteration in the quantity, thickness, color, or constituents. Change in the structure of mucin results in increased virulence of the pathogens.
In such cases, mucin indicates a certain illness or susceptibility to a particular disease.
1. Production of Too Much Mucus:
-
One notices mucus either when it is produced in too much quantity or when there is a change in its texture and consistency. The mucus produced is thick and sticky in the presence of an infection. It inflames the mucous membranes lining the nose and the remaining portions of the airway, stimulating certain glands to produce large quantities of mucus. The mucus gets thicker with an accumulation of infectious bacteria, and the immune cells that arrive to counter the infection, in turn, stimulate the production of more mucus.
-
Excess mucus can be troublesome for the patients in terms of a clogged nose, runny nose, and post-nasal drips (excess mucus accumulates in the back of the nose and drips down to the throat). In addition, post-nasal drip is a frequent cause of cough.
-
Allergies stimulate the body to produce excess mucus. Allergy is a hypersensitive reaction of the body's immune system to substances like dust, pollen, or animal dander, and this will stimulate the airways to produce substances called histamine. Histamine causes swelling of the glands and mucous membranes of the airway to produce more mucus.
-
Two types of secretions are produced in the airways depending on the triggering factors. Allergies, spicy food, and cold weather result in the production of watery mucus. Thicker mucus is produced in the presence of a common cold caused by virus infection and sinusitis caused by bacterial infection.
-
Excess mucous production that lasts for a short duration is often common due to less serious pathologies. However, too much mucous produced for a long period may contribute to some serious pathologies like cystic fibrosis, a genetic condition characterized by excessive thick and sticky glue-like mucus.
2. Changes in Mucus Color:
-
Mucus produced by the body may have a range of colors. Normally clear when the phlegm is cloudy or yellowish. Inflammation of the airways produces certain proteins, which gives a yellowish-gray tint to the mucus.
-
The mucus is usually brown or black in heavy smokers and in some lung diseases.
-
Bacterial infections produce greenish, brownish, and bloody-colored mucus. However, the mucus color cannot be the sole criterion for diagnosing a disease, and physicians must rely on other symptoms and clinical findings to diagnose and treat a problem.
Conclusion
From the above review, it is clear that despite the unpleasant nature of phlegm, it plays a crucial role in maintaining health. From lubrication and protection of internal organs to defense against harmful microorganisms, it has important roles to play. Physicians describe it as a layer of protection between the human body and the outside world. More studies are needed to explore the protective nature of the marvelous mucus.
