VOMITING AS A DEFENSIVE REFLEX

Vomiting is the expulsion of the contents of the stomach through the mouth. Vomiting is often preceded by nausea, sweating, and excessive salivation, although it can occur without warning. It is controlled by a specific part of the brain stem, called the vomiting center, that can be stimulated in several ways.

Most commonly, the center is excited by nerve impulses sent from the gastrointestinal tract (the mouth, esophagus, stomach, and intestines) when any part of the tract is overly distended (swollen), irritated, or excited. Nerve impulses may also come from the balancing mechanism of the inner ear. The vomiting center then sends impulses to the abdominal muscles involved in vomiting. The muscles of the abdomen contract and the diaphragm (the muscular partition between the chest and abdominal cavities) push downward. These contractions compress the stomach, raising the internal pressure. The esophageal sphincter (muscle between the stomach and the esophagus) then relaxes, forcing up the contents of the stomach.

Vomiting associated with irritation of the gastrointestinal tract can occur as the result of improper eating; food poisoning; stomach irritations brought about by chemicals, drugs, or excessive amounts of alcohol; gastrointestinal obstructions; and many infectious diseases.

It also may occur during pregnancy, usually from the 5th or 6th week through the 12th week, and is most likely caused by fluctuating hormone levels. Nausea and vomiting are experienced by more than 50 percent of pregnant women during the first trimester. These symptoms are referred to as morning sickness, although they can occur at any time of the day. They may be distressing, but they cause no adverse effect on the fetus. Drug therapy is not only unnecessary; it should be avoided unless proved safe for the fetus. Treatment involves rest and intake of frequent small meals and foods rich in pyridoxine (vitamin B6).

Vomiting sometimes occurs because the vomiting center has been excited by impulses stimulated by stomach-turning sights or odors, by particular drugs and anesthesia, or by the motion of a ship, car, or airplane.

JONES. H. MUNANG'ANDU (author)
Motivational speaker, health commentator &
Health practitioner
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What is food to one man is bitter poison to others but if the art of turning poison to food is mastered then the name of the dish cannot be spoiled.