Mucus

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Mucus cells.

In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. It is a viscous colloid containing antiseptic enzymes (such as lysozyme) and immunoglobulins that serves to protect epithelial cells in the respiratory, gastrointestinal, urogenital, visual, and auditory systems in mammals; the epidermis in amphibians; and the gills in fish. Snails, slugs, hagfish, and certain invertebrates also produce external mucus, which in addition to serving a protective function, can facilitate movement and play a role in communication.

Mucus also contains mucins, produced by goblet cells in the mucous membranes and submucosal glands, and inorganic salts suspended in water. The average human body produces about a liter of mucus per day.^[1]

Most of this article is about mucus in humans and other mammals.

[edit] 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.

[edit] Reproductive system

In the female reproductive system, cervical mucus prevents infection. The consistency of cervical mucus varies depending on the stage of a woman's menstrual cycle. At ovulation cervical mucus is clear, runny, and conducive to sperm; post-ovulation, mucus becomes thicker and is more likely to block sperm.

In the male reproductive system, the seminal vesicles contribute up to 60% of the total volume of the semen and contain mucus, amino acids, and fructose as the main energy source for the sperm.

[edit] See also

• Empty nose syndrome
• Spinnbarkeit

[edit] References