Burping

Burping, also known as belching, ructus or eructation, is the release of gasfrom the digestive tract (mainly esophagusand stomach) through the mouth. It is often accompanied with a typical sound.

Physiology

Burping is typically caused by eating or drinking too fast, and thereby swallowing (aerophagia) and subsequently expelling air, in which case the expelled gas is a mixture of nitrogenand oxygen. Burps can also be caused by imbibing carbonateddrinks such as beer, soft drinks, or champagne, in which case the expelled gas is carbon dioxidefrom the drink itself. Gastroesophageal reflux diseasecan also cause involuntary burping. Some studies ([1]) have suggested that aerophagia is not the primary culprit but that burping is in fact a learned (social) behaviour.

The sound of burping is caused by the vibrationof the cardia(esophagealsphincter) as the gas passes through it. The current world record for the loudest burp is 118.1 decibels, set by Paul Hunnfrom London, England. (This would be noticeably louder than a chainsaw in a 1 meter diameter.) Similar sounds, such as that created by Tupperware, are sometimes also referred to as burps.

Social context and etiquette

In the Western world, audible burping is considered impolite, although generally not as much as flatulence. Some people will cover the mouth with their hand in the same fashion as one used to guise a yawn. However, burping is viewed as acceptable and humorous among young children and some adults. Often times, children engage in burping contests to determine who can produce the loudest burp. In Saudi Arabia, Japanand many other countries, burping after eating is considered complimentary to the chef.

Infant burping

Babiesare particularly subject to accumulation of gas in the stomach whilst feeding, and this can cause considerable agitation to the child unless it is burped. The act of burping an infant involves placing the child in a position conducive to gas expulsion (for example over the adult's shoulder, with the infant's stomach resting on the adult's chest) and then lightly patting or rubbing it on the lower back so that it burps.

Because burping can cause vomitingin infants, a euphemistically-named burp cloth or burp pad is sometimes employed on the shoulder to protect the adult's clothing.

"Burped" speech

It is possible to voluntarily induce burping by swallowing air and then expelling it, and by manipulation of the vocal tractproduce burped speech.

While this is often employed by children as a means of entertainment or competition, it can also act as an alternative means of vocalisationfor people who have undergone a laryngectomy, with the burp replacing laryngeal phonation. This is known as esophageal speech.

In animals

Other mammals, such as cowsand sheepalso burp; in these cases, the gas expelled is actually methaneproduced as a byproduct of the animal's digestive process. Anaerobic organismssuch as Escherichia coli (E. coli) and methanogenicarchaeaproduce this effect. An average cow is thought to emit between 542 litres(if located in a barn) and 600 litres (if in a field) of methane per day through burping and farting, making commercially farmed cattle a major contributor to the greenhouse effect. This has led scientists at the Commonwealth Scientific and Industrial Research Organisation of Perth, Australia, to develop an anti-methanogen vaccine to minimize methane in cattle burps [2].

Some fishare also known to expel air from their gills; here the burp is produced by gas being expelled from the gas bladder.

Other animals, such as horsesand rats, completely lack the ability to burp (or vomit) at all. Cats, on the contrary, can burp (and vomit).

External links

• Burping as a behavioural problem
• Cow methane productionda:Bøvs

de:rülpsen es:Eructo it:Eruttazione lt:Raugulys nl:Boer (geluid)

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Burping Wikipedia article Burping.