What happens in your body during a sneeze, what causes it and why?

Question

I was just wondering this the other day. I know what a sneeze is, but what happens in your body when you sneeze. And why do the sun and other bright lights induce a sneeze? Just curious! =) (And if you truly don't know don't waste your time trying to answer.)

Answer 1

Sneezing when you look at the sun is called photic sneeze reflex - also known as autosomal dominant compelling helio-opthalmic outburst (ACHOO). It is not known exactly how or why this occurs, but it's assumed that it happens due to an accidental crossing of nerve signals in the 4th cranial nerve nucleus (the area in the brain that tells the body to sneeze). Btw, photic sneeze reflex is genetic - so it's very likely that one of your parents also has a 'sun sneeze'.

Referring to the first part of your question: a stimulus causes the nervous system (4th cranial nerve nucleus) to sneeze - it can be anything from cold air, allergens, bright light, bacteria, etc. The nervous system wants to expel any air in the body to rid it of whatever the stimulus may be. Therefore, it expels the air in a spasmic, forceful outburst through the nose and mouth. Your eyes close during this as a reflex, and it's thought, to protect the eyes from the possible bacteria. During a sneeze, the pressure inside your chest changes and affects blood flow to the heart and can alter the heartbeat, but this is quick and temporary - your heart does NOT stop beating during a sneeze.

Answer 2

Photic Sneezing occurs when you see a bright light. Photic is another word for light and photic sneezing is something that you is hereditary.

Sneezing is generally caused by irritation in the throat, lungs, or in the passages of the nose. The sneeze is a reflexive, convulsive expulsion of air from the lungs and out the nose and mouth. This air can reach speeds of 155 MPH

As a side note, sneezing into your hand only spreads germs. If you do not have a tissue, the proper way to "catch" a sneeze is to do it into your sleeve at the inside of your elbow.

Answer 3

http://www.healthline.com/search?q1=sneezing&utm_source=gale&utm_medium=google&utm_campaign=serp&utm_term=sneezing

Sneezing is caused by irritation to the mucous membranes of the nose or throat. It can be very bothersome, but is generally not a sign of a serious problem.


Common Causes

Allergy to pollen, mold, dander, dust (hay fever)
Virus infections (common cold, upper respiratory tract infections)
Drug withdrawal
Corticosteroid inhalation
Nasal irritants such as dust and powders

this one says it all

http://en.wikipedia.org/wiki/Sneeze
A sternutation, sternutatory reflex or, more commonly known, sneeze is a semi-autonomous, convulsive expulsion of air from the nose and mouth. This air can reach speeds of 70 m/s (250 km/h or 155 MPH). Sneezes spread disease by producing infectious droplets that are 0.5 to 5 µm in diameter, about 40,000 such droplets can be produced by a single sneeze.[1]
Sneezing is generally caused by irritation and some times bacterial clog up in the throat, lungs or in the passages of the nose. Allergens such as pollens, pet dander, house dust mites, as well as nonallergenic particles are usually harmless, but when they irritate the nose the body responds by expelling them from the nasal passages. The nose mistakes strong odors, sudden chills, bright lights (see photic sneeze reflex), and even orgasms in some people for nasal irritants, and it tries to defend itself with a sneeze

Answer 4

it is a allegic reaction to the tickling