21 Anti-emetics, Anti-diarrhoeals and Laxatives Flashcards

1
Q

What is the difference between vomiting and regurgitation?

A

Vomiting= Involuntary, forceful expulsion of gastric contents

Regurgitation= effortless expulsion- contents might be in oesophagus

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2
Q

How does vomiting occur?

A

Vomiting centre in medulla signals to vomit

  1. Nausea, salivation, sweating
  2. Retrograde peristalsis
  3. Deep inspiration
  4. Closure of glottis (choking if not closed- eg if drugged)
  5. Adbominal muscles contract
  6. Lower oesophageal spincter relaxes
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3
Q

Where is the chemoreceptor trigger zone (CTZ)? What are the 4 triggers?

A

CTZ= area of medulla- area postrema- floor of 4th ventricle- on blood side of blood brain barrier

  1. Sensory afferents via midbrain (eg seeing something gross)
  2. Vestibular nuclei (motion sickness)
  3. Visceral afferents from gut - via vagus nerve
    1. eg problem in gut- sends signals to CTZ
  4. Direct triggers (eg chemotherapy/hormones)
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