Veterinary Clinical Medicine-I (General and Systemic)

PATHWAYS OF VOMITING

• When the vomitus passes through the pharyngeal cavity, nasopharynx and glottis are closed to prevent aspiration.
• Emetic center : Located in medulla oblongata in brain.
  • Receptors located throughout the abdominal viscera. Diseases or irritation of the gastro intestinal tract, other abdominal organs or peritoneum  stimulate vomiting through vagal afferent pathways 
  • Receptors in kidney, uterus, urinary bladder send afferent impulses through sympathetic nerves
  • Receptors in pharynx, tonsillar fossae  through afferent fibers of the glassopharyngeal nerve.
  • CNS disease through direct extension of inflammatory stimuli, hydrocephalus or space occupying lesions. CSF increase, cereblral edema, infection, neoplasia.
  • Fear, stress or pain: Stimulation of higher centers in cerebro cortex- psychogenic vomiting 
  • Cyclic vomiting in dog is associated with an autonomic / visceral epilepsy arising from limbic region.