The nasal cavity (or nasal fossa) is a large air filled space above and behind the nose in the middle of the face. Each cavity is the continuation of one of the two nostrils.
The nasal cavity conditions the air to be received by the other areas of the respiratory tract. Owing to the large surface area provided by the nasal concha, the air passing through the nasal cavity is warmed or cooled to within 1 degree of body temperature. In addition, the air is humidified, and dust and other particulate matter is removed by vibrissae, short, thick hairs, present in the vestibule. The cilia of the respiratory epithelium move the particulate matter towards the pharynx where it passes into the esophagus and is digested in the stomach. It also aids in our sense of smell and taste.
Dried nasal mucus, pieces of which are colloquially known as boogies or boogers or bogeys, is found in the nose and is a result of drying of the normally viscous colloidal mucus (commonly known as snot).
The mucous membranes in the nasal cavity constantly produce a wet mucus that lines the cavity and removes dust and pathogens from the air flowing through. For the most part, the cilia that also line the cavity work to move the mucus down the nasal cavity to the pharynx where it can be swallowed. Not all of the mucus stays fluid enough to be moved by the cilia. The closer the mucus is to being in the nasal vestibule and near the nostril opening, the more moisture it loses to the outside air, and the more likely it is to dry out and become stuck.
Eating mucus is the act of extracting nasal mucus with one's finger (rhinotillexis) and the succeeding action of ingesting the mucus from the nose-picking (mucophagy). Nasal mucus is also termed as boogers, snot, bogeys, dried nasal mucus, mucus secretion, and other related terms including comerse los mocos (to eat one's snot).
Mucophagy is a common behavior in children. Some scientists argue that mucophagy provides benefits for the human body. Friedrich Bischinger, an Austrian doctor specializing in lungs advocates using fingers to pick and ingesting nasal mucus, states people who do so get "a natural boost to their immune system." The mucus contains a "cocktail of antiseptic enzymes that kill or weaken many of the bacteria that become entangled in it," so reintroducing the 'crippled' microorganisms "may afford the immune system an opportunity to produce antibodies in relative safety." However, this action is condemned in most cultures and societies which try to prevent development of the habit and attempt to break it if already established. Mucophagy is a source of mockery and entertainment in the media thus confirming the social scorn previously mentioned.
In the animal kingdom, the general term gland falls into two major categories with further subtypes falling under each of these.
An Exocrine gland is distinguished by the fact that it excretes its essential product by way of a duct to some environment external to itself, be it either inside the body or on a surface of the body.