Vomiting

• Vomiting or emesis is the forceful expulsion of gastric contents out through the mouth and generally perceived as being caused by abnormal gastric motility.

• Stomach, esophagus and associated sphincter relaxes during vomiting.

• The major force of expulsion comes from contraction of respiratory muscles (diaphragm and abdominal muscles which aid during active expiration)

• Vomiting is coordinated by Vomiting Center in medulla.

• It begins with a deep inspiration and closure of glottis to prevent vomited material enter respiratory passage and uvula is elevated to close the nasal cavity.

• The contracting diaphragm descends down on stomach and contraction of abdominal muscles compresses the abdominal cavity, increasing the intra-abdominal pressure and forcing the abdominal viscera upward.

• This would cause the gastric contents forced upward through the relaxed sphincter and esophagus and out through mouth

• Vomiting is usually preceded by profuse salivation, sweating, rapid heart beat, and sensation of nausea.

• Causes of Vomiting:
• • Tactile (touch) stimulation of the back of the throat
  • Irritation or distention of stomach
  • Elevated intracranial pressure from cerebral hemorrhage
  • Rotation or acceleration of head
  • Chemical Agents
  • Emotional factors
  
  
• Effect of Vomiting

- Body experience large losses of secreted fluids and acids that normally would be reabsorbed.
- Reduction of plasma volume can lead to dehydration and circulatory and loss of acid would lead to metabolic alkalosis
- Vomiting also beneficial in removing noxious material in stomach (emetics given in the case of accidental
ingestion of poison)