What is vomiting?
Vomiting (or emesis) is the forceful expulsion through the mouth of the contents of one's stomach. It is a mechanism for expelling ingested illness-causing food poisons. Vomiting is the ejection of food and other matter from the stomach through the mouth, often preceded by nausea. The process is initiated by stimulation of the vomiting center of the brain by nerve impulses from the gastrointestinal tract or other part of the body. The vomiting center then sends out nerve impulses that precipitate spasmodic muscular contractions of the stomach wall and downward spasms of the diaphragm. The pressure
generated then forces up the contents of the stomach. The vomiting mechanism may be in response to local irritation (diseases or disorders of the gastrointestinal tract, overburdening of the capacity and digestive capabilities of the stomach, ingestion of harmful foods or substances) or result from a metabolic disturbance (as in pregnancy) or from disorders or stimulation of the nervous system (e.g., migraine, motion sickness, infectious disease, brain tumor or injury, disagreeable odors). Vomiting may also be a reflex action to other spasmodic conditions (whooping cough, gagging).
The act may be triggered by stimuli which might indicate the possibility of poisoning, such as motion sickness, or sight of decayed food, or other people vomiting. It can also be induced with an emetic or prevented with an antiemetic. Nausea also may occur after surgery due to the chemicals employed, see Postoperative nausea and vomiting. Vomiting sometimes also occurs in response to an emotional trauma, or after a concussion; in the latter case it can indicate that the head injury is moderate or severe and requires immediate medical attention. The act may also be triggered intentionally by stimulating the constrictor muscle located in the back of the throat with a finger or other object. It may be triggered voluntarily due to a psychological disorder such as anorexia nervosa or bulimia or to remove a poison in case such has been ingested. (Note: Some poisons should not be vomited as they may be more toxic when inhaled. Always contact a Poison Control center before inducing vomiting.) The feeling that one is about to vomit is called nausea. On airplanes and ferries special bags are supplied for this purpose. Alternatively, a special disposable bag is used containing absorbent material that solidifies the vomit in 5 to 10 seconds, making it convenient and safe to keep (leakproof, puncture resistant, odorless) until there is an opportunity to dispose of it (conveniently like regular garbage).
Vomiting is a complex, coordinated reflex orchestrated by the vomiting center of the brain. Receptors on the floor of the fourth ventricle of the brain represent a chemoreceptor trigger zone, stimulation of which can lead to vomiting. The chemoreceptor zone lies outside the blood-brain barrier, and can therefore be stimulated by blood-borne drugs which can stimulate vomiting, or inhibit it. Vomiting is ordinarily preceded by retching. The purpose of retching is to build up the pressure needed to expel the stomach contents from the body. In retching, the body makes movements similar to vomiting. These spasms build up pressure within the chest cavity. When a sufficient amount of pressure has been created, the diaphragm transfers the pressure from the chest to the abdomen, and this pressure then results in actual vomiting.
More information on vomiting
What is vomiting? - Vomiting (or emesis) is the forceful expulsion through the mouth of the contents of one's stomach. Vomiting is a mechanism for expelling ingested illness-causing food poisons.
What causes vomiting? - Vomiting may be triggered by stimuli which might indicate the possibility of poisoning, such as motion sickness, or sight of decayed food, or other people vomiting.
How is vomiting diagnosed? - Examination of the micro-fungal content of vomit can be a means of indentifying illness. Also known as vomitus, vomit contains a high concentration of hydronium.
Infant and child vomiting - Vomiting can be part of many illnesses in children and babies. Vomiting is common for babies and young children. Vomiting occurs when food is brought back up from the stomach.
What's the treatment for vomiting? - Treatment for vomiting includes drinking gradually larger amounts of clear liquids, avoiding solid food, resting and temporarily discontinuing all oral medications.
How to prevent vomiting? - Vomiting can be prevented by drinking small amounts of clear, sweetened liquids such as soda pop, fruit juices and popsicles. Live a hygienic life to avoid bad bacteria infections.
Nausea and vomiting - Nausea is the sensation of unease and discomfort from the stomach, with the sufferers feeling that they may vomit. Nausea and vomiting are controlled by the same parts of the brain.