Vomiting is a forceful action accomplished by a fierce, downward contraction of the diaphragm muscle. At the same time, the abdominal muscles tighten against a relaxed stomach with an open gastroesophageal sphincter. The contents of the stomach are propelled up and out.
As part of a bodily reflex, you may produce more saliva just before vomiting.
Vomiting is a complex, coordinated reflex orchestrated by the vomiting center of the brain. It responds to signals coming from:
•The mouth, stomach, and intestines
•The bloodstream, which may contain medicines or infections
•The balancing systems in the ear (motion sickness)
•The brain itself, including unsettling sights, smells, or thoughts
An amazing variety of stimuli can trigger vomiting, from migraines to kidney stones. Sometimes, just seeing someone else vomit will start you vomiting, in your body's effort to protect you from possible exposure to the same danger.
Vomiting is common. Almost all children will vomit several times during their childhood. In most cases, it is due to a viral gastrointestinal infection.
Spitting up, the gentle sloshing of stomach contents up and out of the mouth, sometimes with a burp, is an entirely different process. Some spitting up is normal for babies, and usually gets gradually better over time. If spitting up worsens or is more frequent, it might be reflux disease. Discuss this with your child's doctor.
Most of the time, nausea and vomiting do not require urgent medical attention. However, if the symptoms continue for days, they are severe, or you cannot keep down any food or fluids, you may have a more serious condition.
Dehydration is the main concern with most vomiting. How fast you become dehydrated...