Defensive vomiting refers to the use of
emesis
Vomiting (also known as emesis, puking and throwing up) is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like food poisoning, gastroenteritis, pregna ...
by animals to defend against ingested
pathogen
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...
s or against
predators
Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
.
In humans
Vomiting serves an evolutionary purpose for humans by preventing the ingestion of something harmful, and by expelling noxious substances once ingested.
Vomiting excessive amounts of
alcohol
Alcohol may refer to:
Common uses
* Alcohol (chemistry), a class of compounds
* Ethanol, one of several alcohols, commonly known as alcohol in everyday life
** Alcohol (drug), intoxicant found in alcoholic beverages
** Alcoholic beverage, an alco ...
is an attempt by the body to prevent
alcohol poisoning
Alcohol intoxication, commonly described in higher doses as drunkenness or inebriation, and known in overdose as alcohol poisoning, is the behavior and physical effects caused by recent consumption of alcohol. The technical term ''intoxication ...
and death. Vomiting may also be caused by other drugs, such as
opiates
An opiate is an alkaloid substance derived from opium (or poppy straw). It differs from the similar term ''opioid'' in that the latter is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain ( ...
, or toxins found in some foods and plants.
Food allergies
A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressu ...
and sensitivities, such as
lactose intolerance
Lactose intolerance is caused by a lessened ability or a complete inability to digest lactose, a sugar found in dairy products. Humans vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain ...
, can cause vomiting.
Morning sickness
Morning sickness, also called nausea and vomiting of pregnancy (NVP), is a symptom of pregnancy. Despite the name, nausea or vomiting can occur at any time during the day. Typically the symptoms occur between the 4th and 16th weeks of pregnan ...
may have a defensive purpose. One professor has posited that morning sickness discourages pregnant women from eating meat and strong-tasting vegetables, which may contain toxins and microorganisms. If ingested, the
fetus
A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...
might be harmed in the first 18 weeks of pregnancy.
In animals
Turkey vultures
Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...
will vomit to dispel any disturbing animal. They can propel their vomit up to .
The
European roller
The European roller (''Coracias garrulus'') is the only member of the Coraciidae, roller family breeding in Europe. Its range extends into the Maghreb, West Asia and Central Asia. It winters in southern Africa, primarily in dry wooded savanna and ...
, a much smaller bird found in parts of
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
,
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
,
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
, and the
Middle East
The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq.
The term came into widespread usage by the United Kingdom and western Eur ...
, uses vomit in a different way. A baby European roller will vomit a foul-smelling orange liquid onto itself to turn away a predator. The smell also warns the parents to return to the nest, and to be wary of predators.
See also
*
Area postrema
The area postrema, a paired structure in the medulla oblongata of the brainstem, is a circumventricular organ having permeable capillaries and sensory neurons that enable its role to detect circulating chemical messengers in the blood and tra ...
, the part of the brain that controls vomiting
*
Chemoreceptor trigger zone
The chemoreceptor trigger zone (CTZ) is an area of the medulla oblongata that receives inputs from blood-borne drugs or hormones, and communicates with other structures in the vomiting center to initiate vomiting. The CTZ is located within the are ...
, the part of the area postrema that relays signals through the blood-brain barrier
References
{{reflist
Reflexes
Vomiting