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Flashcards in Emesis Deck (8)
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1
Q

*Emesis

A

Triggered by local GI irritants signaling Vomiting Center

Triggered by chemicals or drugs binding to the Chemoreceptor Trigger Zone

2
Q

Stomach sends signal thru ______ to the Vomiting Center

A

Vagus nerve

- activate motor activity responsible for vomiting

3
Q

CRTZ

A

Located bilaterally on the floor of the 4th ventricle

  • “hole” in the blood brain barrier
  • stimulated by drugs and toxins: apomorphine, morphine, xylazine (cats), chemotherapeutic drugs
4
Q

Prelude to vomiting

A

Antiperistalsis precedes vomiting

  • may begin as distal as the ileum
  • wave travels backwards at 2-3 cm/sec
  • pushes upward along the tract
  • gastric and duodenal distention/irritation provides the trigger
5
Q

Vomiting chain of events

A
  • strong contraction in stomach and duodenum
  • partial relaxation of lower esophageal sphincter
  • deep intake of breath
  • opening of upper esophageal sphincter
  • closing of glottis
  • lifting of soft palate against posterior nares
  • strong downward contraction of esophagus
  • simultaneous contraction of abdominal muscles
  • complete relaxation of lower esophageal sphincter
  • both involuntary and voluntary components*
6
Q

Motion sickness

A

Sudden changes in motion stimulates receptors in the vestibular labyrinth
- vestibular receptors –> vestibular nuclei –> cerebellum –> CRTZ –> vomiting center

7
Q

Primary (local) GI factors

A
  • chemical irritant
  • physical irritant
  • distention
8
Q

Stimulation of CRTZ

A
  • drugs
  • toxins
  • chemical/metabolic byproducts