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
2
Q
How does vomiting occur?
A
Vomiting centre in medulla signals to vomit
- Nausea, salivation, sweating
- Retrograde peristalsis
- Deep inspiration
- Closure of glottis (choking if not closed- eg if drugged)
- Adbominal muscles contract
- Lower oesophageal spincter relaxes
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
- Sensory afferents via midbrain (eg seeing something gross)
- Vestibular nuclei (motion sickness)
- Visceral afferents from gut - via vagus nerve
- eg problem in gut- sends signals to CTZ
- Direct triggers (eg chemotherapy/hormones)