Mucus

Mucus is a slippery secretion of the lining of various membranes in the body (mucous membranes). It is a viscous colloid containing antiseptic enzymes (such as lysozyme) and immunoglobulins. Mucus is produced by goblet cells in the mucous membranes that cover the surfaces of the membranes. It is made up of mucins and inorganic salts suspended in water.

Mucus serves many different functions within the processes in an animals body:

Respiratory system

In the respiratory system, it catches unknown matter and tries to prevent it from entering the body, especially in the nose. Mucus aids in the protection of the lungs by trapping foreign particles that enter the nose during normal breathing. Additionally, it prevents tissues from drying out.

Increased mucus production in the respiratory tract is a symptom of many common diseases, such as the common cold. The presence of mucus in the nose and throat is normal, but increased quantities can impede comfortable breathing and must be cleared by blowing the nose or expectorating phlegm from the throat. Among the components of nasal mucus are tears.

Dried nasal mucus (vulgarly or colloquially called "snot", "booger(s)" (US) or "bogey" (UK)) is partially solidified mucus from the nose. Dried nasal mucus forms when the mucus traps dust and other particles in the air. Mucus dries around the particle and hardens, somewhat like a pearl forming in an oyster. Since catching foreign particles is one of the main functions of nasal mucus, the presence of dried nasal mucus is a good indicator of a properly functioning nose.

Digestive system

In the digestive system, mucus is used as a lubricant for materials which must pass over membranes, e.g., food passing down the esophagus. A layer of mucus along the inner walls of the stomach is vital to protect the cell linings of that organ from the highly acidic environment within it.

Reproductive system

In the reproductive system, cervical mucus prevents infection and helps the movement of the penis during sexual intercourse. When thin, cervical mucus helps the movement of spermatozoa.

See also

*Nose-picking
*Phlegm
*Empty nose syndrome