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Sneeze

Sneeze

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A sneeze is a semi-autonomous, convulsive expulsion of air from the lungs through the nose and mouth, usually caused by foreign particles irritating the nasal mucosa. Sneezing can also be triggered through sudden exposure to bright light
Photic sneeze reflex
The photic sneeze reflex is a condition of uncontrollable sneezing in response to numerous stimuli, such as looking at bright lights or periocular injection...

, a particularly full stomach
Snatiation
Snatiation is a medical disorder characterized by uncontrollable bursts of sneezing brought on by fullness of the stomach, and typically observed in sufferers immediately after a large meal. It is thought to be passed along genetically as an autosomal dominant trait...

, or viral infection, and can lead to the spread of disease.

Biological elements


The function of sneezing is to expel mucus containing foreign particles or irritants and cleanse the nasal cavity. During a sneeze, the soft palate and uvula depress while the back of the tongue elevates to partially close the passage to the mouth so that air ejected from the lungs may be expelled through the nose. Because the closing of the mouth is partial, a considerable amount of this air is usually also expelled from the mouth. The force and extent of the expulsion of the air through the nose varies.

Overall mechanism


Sneezing typically occurs when foreign particles or sufficient external stimulants pass through the nasal hairs to reach the nasal mucosa. This triggers the release of histamine
Histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...

s, which irritate the nerve cells in the nose, resulting in signals being sent to the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 to initiate the sneeze through the trigeminal nerve network
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...

. The brain then relates this initial signal, activates the pharyngeal
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

 and tracheal
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...

 muscles and creates a large opening of the nasal and oral cavities, resulting in a powerful release of air and bioparticles. The powerful nature of a sneeze is attributed to its involvement of numerous organs of the upper body – it is a reflexive response
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...

 involving the face, throat, and chest muscles.

Sneezing is also triggered by sinus nerve stimulation caused by sinus infection and allergies.

Outside of irritating foreign particles, allergies or possible illness, another stimulus is sudden exposure to bright light - a condition known as photic sneeze reflex
Photic sneeze reflex
The photic sneeze reflex is a condition of uncontrollable sneezing in response to numerous stimuli, such as looking at bright lights or periocular injection...

.

A rarer trigger, observed in some individuals, is the fullness of the stomach immediately after a large meal. This is known as snatiation
Snatiation
Snatiation is a medical disorder characterized by uncontrollable bursts of sneezing brought on by fullness of the stomach, and typically observed in sufferers immediately after a large meal. It is thought to be passed along genetically as an autosomal dominant trait...

 and is regarded a medical disorder passed along genetically as an autosomal dominant trait.

Sneezing cannot occur during sleep due to REM atonia - a bodily state wherein motor neurons are not stimulated and reflex signals are not relayed to the brain. Sufficient external stimulants, however, may cause a person to wake from their sleep for the purpose of sneezing, although any sneezing occurring afterwards would take place with a partially awake status at minimum.

The sneeze reflex involves contraction of a number of different muscles and muscle groups throughout the body, typically including the eyelids. The common suggestion that it is impossible to sneeze with one's eyes open is, however, inaccurate.

Epidemiology


While generally harmless in healthy individuals, sneezes spread disease through the infectious
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

 aerosol
Aerosol
Technically, an aerosol is a suspension of fine solid particles or liquid droplets in a gas. Examples are clouds, and air pollution such as smog and smoke. In general conversation, aerosol usually refers to an aerosol spray can or the output of such a can...

 droplets, commonly ranging from 0.5 to 5 µm. 40,000 droplets can be produced by a sneeze. To avoid the possibility of thus spreading disease (such as the flu), one should hold the forearm
Forearm
-See also:*Forearm flexors*Forearm muscles...

 or the inside of the elbow
Elbow
The human elbow is the region surrounding the elbow-joint—the ginglymus or hinge joint in the middle of the arm. Three bones form the elbow joint: the humerus of the upper arm, and the paired radius and ulna of the forearm....

 in front of one's mouth and nose when sneezing. Using one's hand for that purpose is inappropriate, since it promotes spreading germs through commonly touched objects (most notably doorknobs).

Preventive measures


Examples of preventive techniques are: the deep exhalation of the air in the lungs that would otherwise be used in the act of sneezing, holding the breath in while counting to ten or gently pinching the bridge of the nose for several seconds.

Proven methods to reduce sneezing generally advocate reducing interaction with irritant
Irritation
Irritation or exacerbation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant...

s, such as keeping pets out of the house to avoid animal dander
Dander
Dander is an informal term for a material shed from the body of various animals, similar to dandruff. It may contain scales of dried skin and hair, or feathers. It is a cause of allergies in humans....

; ensuring the timely and continuous removal of dirt and dust
Dust
Dust consists of particles in the atmosphere that arise from various sources such as soil dust lifted up by wind , volcanic eruptions, and pollution...

 particles through proper housekeeping; replacing filters for furnaces and air-handling units; air filtration devices and humidifier
Humidifier
A humidifier is a household appliance that increases humidity in a single room or in the entire house. There are point-of-use humidifiers, which are commonly used to humidify a single room, and whole-house or furnace humidifiers, which connect to a home's HVAC system to provide humidity to the...

s; and staying away from industrial and agricultural zones. Some people, however, find sneezes to be pleasurable and would not want to prevent them.

Historic instances and practices


In Ancient Greece
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

, sneezes were believed to be prophetic signs from the gods. In 401 BC, for instance, the Athenian
Athens
Athens , is the capital and largest city of Greece. Athens dominates the Attica region and is one of the world's oldest cities, as its recorded history spans around 3,400 years. Classical Athens was a powerful city-state...

 general Xenophon
Xenophon
Xenophon , son of Gryllus, of the deme Erchia of Athens, also known as Xenophon of Athens, was a Greek historian, soldier, mercenary, philosopher and a contemporary and admirer of Socrates...

 gave speech exhorting his fellow soldiers to fight against the Persians. A soldier
Soldier
A soldier is a member of the land component of national armed forces; whereas a soldier hired for service in a foreign army would be termed a mercenary...

 underscored his conclusion with a sneeze. Thinking that this sneeze was a favorable sign from the gods, the soldiers were impressed. Another divine moment of sneezing for the Greeks occurs in the story of Odysseus
Odysseus
Odysseus or Ulysses was a legendary Greek king of Ithaca and the hero of Homer's epic poem the Odyssey. Odysseus also plays a key role in Homer's Iliad and other works in the Epic Cycle....

. His waiting wife Penelope
Penelope
In Homer's Odyssey, Penelope is the faithful wife of Odysseus, who keeps her suitors at bay in his long absence and is eventually reunited with him....

, hearing Odysseus
Odysseus
Odysseus or Ulysses was a legendary Greek king of Ithaca and the hero of Homer's epic poem the Odyssey. Odysseus also plays a key role in Homer's Iliad and other works in the Epic Cycle....

 may be alive, says that he and his son would take revenge on the suitors if he were to return. At that moment, their son sneezes loudly and Penelope laughs with joy, reassured that it is a sign from the gods (Odyssey
Odyssey
The Odyssey is one of two major ancient Greek epic poems attributed to Homer. It is, in part, a sequel to the Iliad, the other work ascribed to Homer. The poem is fundamental to the modern Western canon, and is the second—the Iliad being the first—extant work of Western literature...

 17: 541-550).

In Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, principally around the early Middle Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

, it was believed that one's life was in fact tied to one's breath - a belief reflected in the word "expire" (originally meaning "to exhale") gaining the additional meaning of "to come to an end" or "to die". This connection, coupled with the significant amount of breath expelled from the body during a sneeze, had likely led people to believe that sneezing could easily be fatal. This theory, if proven conclusively, could in turn explain the reasoning behind the traditional "God bless you" response to a sneeze, the origins of which are currently unclear. (see "Traditional Responses To A Sneeze" below for alternative explanations). Sir Raymond Henry Payne Crawfurd, for instance, the late registrar of the Royal College of Physicians
Royal College of Physicians
The Royal College of Physicians of London was founded in 1518 as the College of Physicians by royal charter of King Henry VIII in 1518 - the first medical institution in England to receive a royal charter...

, in his 1909 book "The Last Days of Charles II
Charles II of England
Charles II was monarch of the three kingdoms of England, Scotland, and Ireland.Charles II's father, King Charles I, was executed at Whitehall on 30 January 1649, at the climax of the English Civil War...

", states that, when the controversial monarch was on his deathbed, his medical attendants administered a concoction of cowslips
Primula veris
Primula veris is a flowering plant in the genus Primula. The species is found throughout most of temperate Europe and Asia, and although absent from more northerly areas including much of northwest Scotland, it reappears in northernmost Sutherland and Orkney.-Names:The common name cowslip derives...

 and extract of ammonia
Caltha palustris
Caltha palustris is a herbaceous perennial plant of the buttercup family, native to marshes, fens, ditches and wet woodland in temperate regions of the Northern Hemisphere....

 to promote sneezing. However, it is not known if this promotion of sneezing was done to hasten his death (as coup de grace
Coup de grâce
The expression coup de grâce means a death blow intended to end the suffering of a wounded creature. The phrase can refer to the killing of civilians or soldiers, friends or enemies, with or without the consent of the sufferer...

), or as an ultimate attempt at treatment.

In certain parts of Eastern Asia, particularly in Chinese culture, Japanese culture and Vietnamese culture, a sneeze without an obvious cause was generally perceived as a sign that someone was talking about the sneezer at that very moment. This can be seen in the Book of Songs (a collection of Chinese poems) in ancient China as early as 1000 BC, and this belief is still depicted in present-day manga
Manga
Manga is the Japanese word for "comics" and consists of comics and print cartoons . In the West, the term "manga" has been appropriated to refer specifically to comics created in Japan, or by Japanese authors, in the Japanese language and conforming to the style developed in Japan in the late 19th...

 and anime
Anime
is the Japanese abbreviated pronunciation of "animation". The definition sometimes changes depending on the context. In English-speaking countries, the term most commonly refers to Japanese animated cartoons....

. In China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

, Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

 and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, for instance, there is a superstition
Superstition
Superstition is a belief in supernatural causality: that one event leads to the cause of another without any process in the physical world linking the two events....

 that if talking behind someone's back causes the person being talked about to sneeze; as such, the sneezer can tell if something good is being said (one sneeze), something bad is being said (two sneezes in a row), even if someone is in love with them (three sneezes in a row) or if this is a sign that they are about to catch a cold
Common cold
The common cold is a viral infectious disease of the upper respiratory system, caused primarily by rhinoviruses and coronaviruses. Common symptoms include a cough, sore throat, runny nose, and fever...

 (multiple sneezes).

Parallel beliefs are known to exist around the world, particularly in contemporary Greek, Slavic, Celtic, English, French, and Indian cultures. Similarly, in Nepal
Nepal
Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...

, sneezers are believed to be remembered by someone at that particular moment.

In Indian culture
Culture of India
India's languages, religions, dance, music, architecture, food and customs differ from place to place within the country, but nevertheless possess a commonality....

, especially in northern parts of India
North India
North India, known natively as Uttar Bhārat or Shumālī Hindustān , is a loosely defined region in the northern part of India. The exact meaning of the term varies by usage...

, and also in Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...

, it has been a common superstition
Superstition
Superstition is a belief in supernatural causality: that one event leads to the cause of another without any process in the physical world linking the two events....

 that a sneeze taking place before the start of any work was a sign of impending bad interruption. It was thus customary to pause in order to drink water or break any work rhythm before resuming the job at hand in order to prevent any misfortune from occurring.

Contrarily, in Polish Culture
Culture of Poland
The culture of Poland is closely connected with its intricate 1000 year history Its unique character developed as a result of its geography at the confluence of various European regions...

, especially in what the Poles have known to be their Borderlands, the Kresy
Kresy
The Polish term Kresy refers to a land considered by Poles as historical eastern provinces of their country. Today, it makes western Ukraine, western Belarus, as well as eastern Lithuania, with such major cities, as Lviv, Vilnius, and Hrodna. This territory belonged to the Polish-Lithuanian...

, a popular belief persists that sneezes may be an inauspicious sign that one's mother-in-law speaks ill of their son-in-law at that moment. The same phenomenon is thought to correspond to daughters-in-law and their mothers-in-law. As with other Catholic
Catholic
The word catholic comes from the Greek phrase , meaning "on the whole," "according to the whole" or "in general", and is a combination of the Greek words meaning "about" and meaning "whole"...

 countries, such as Mexico, Italy, or Ireland, the remnants of pagan culture are fostered in Polish peasant idiosyncratic superstitions.

The practice among Islamic culture
Muslim culture
Islamic culture is a term primarily used in secular academia to describe the cultural practices common to historically Islamic peoples. As the religion of Islam originated in 7th century Arabia, the early forms of Muslim culture were predominantly Arab...

, in turn, has largely been based on various Prophetic traditions and the teachings of Muhammad
Muhammad
Muhammad |ligature]] at U+FDF4 ;Arabic pronunciation varies regionally; the first vowel ranges from ~~; the second and the last vowel: ~~~. There are dialects which have no stress. In Egypt, it is pronounced not in religious contexts...

. An example of this is Al-Bukhaari's narrations from Abu Hurayrah that the Islamic prophet once said:

When one of you sneezes, let him say, "Al-hamdu-Lillah" (Praise be to God
God
God is the English name given to a singular being in theistic and deistic religions who is either the sole deity in monotheism, or a single deity in polytheism....

), and let his brother or companion say to him, "Yarhamuk Allah" (May God
God
God is the English name given to a singular being in theistic and deistic religions who is either the sole deity in monotheism, or a single deity in polytheism....

 have mercy on you). If he says, "Yarhamuk-Allah", then let [the sneezer] say, "Yahdeekum Allah wa yuslihu baalakum" (May God
God
God is the English name given to a singular being in theistic and deistic religions who is either the sole deity in monotheism, or a single deity in polytheism....

 guide you and rectify your condition).

Traditional responses to a sneeze



In English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

-speaking countries, the common verbal response to another person's sneeze is "God Bless You" or in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 the much less common "Gesundheit" (the German word for "health"). There are several proposed origins for the use "Bless you" in the context of sneezing:
  • Various alleged but conflicting superstitions relating the sneeze to evil spirits. This includes beliefs that a sneeze could release one's soul, thus leading to its possible capture by lurking evil spirits (as explained in the "Historic instances and practices" section above), or that the evil spirits could enter the body though the open mouth of a sneezing individual, or that the individual is sneezing out sins or evil spirits which had taken residence within the body and is thus in need of the blessing to prevent the exorcised
    Exorcism
    Exorcism is the religious practice of evicting demons or other spiritual entities from a person or place which they are believed to have possessed...

     spirit
    Spirit
    The English word spirit has many differing meanings and connotations, most of them relating to a non-corporeal substance contrasted with the material body.The spirit of a living thing usually refers to or explains its consciousness.The notions of a person's "spirit" and "soul" often also overlap,...

    s from re-entering the body. Some proponents of this last theory have further suggested that it was bad luck to open the mouth again to thank the person who uttered "Bless you" for fear of circumventing the original purpose of the blessing.
  • Some say it came into use during the plague
    Black Death
    The Black Death was one of the most devastating pandemics in human history, peaking in Europe between 1348 and 1350. Of several competing theories, the dominant explanation for the Black Death is the plague theory, which attributes the outbreak to the bacterium Yersinia pestis. Thought to have...

     pandemics of the 14th century. Blessing the individual after showing such a symptom was thought to prevent possible impending death due to the lethal disease.
  • In Renaissance times a superstition was formed claiming one's heart stopped for a very brief moment during the sneeze, saying bless you was a sign of prayer that the heart wouldn't fail possibly the devil's doing by sending demons to clasp the heart in the body's moment of shock from the sneeze.


Common English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

 onomatopoeias for the sneeze sound are hachoo, achoo, atchoo, achew and atishoo, with the first syllable corresponding to the initial exhaling of air, and the last to the sound of the sneeze.

Further reading


External links