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| − | ==The Vomit Reflex== | + | ==[[Vomiting#The Vomit Reflex|The Vomit Reflex]]== |
| − | [[Image:The Vomit Reflex Pathway.jpg|right|thumb|150px|The Vomit Reflex - Copyright nabrown RVC]] | |
| − | *Emesis is the process of vomiting
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| − | *Persistent vomiting can be exhausting and can lead to metabolic alkalosis, dehydration and electrolyte inbalances which may require fluid therapy
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| − | *Extreme cases of persistent vomiting can lead to shock
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| − | *Retching involves the abdominal and chest walls contracting
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| − | *Vomiting includes retching and the action of the diaphragm
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| − | *Diaphragm moves caudal to open the cardia
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| − | *Gastrointestinal tract have protective stimuli to recognise harmful products ingested. The mechanoreceptors and chemoreceptors respond using viscerent afferent pathways.
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| − | *Medulla co-ordinates process
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| − | *Chemoreceptive trigger zone in the 4th ventricle responds to blood and CSF
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| − | *Inputs also from inner ear and higher centres
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| − | *Emetic agents can be used in cases of gastric obstruction and to remove non-corrosive poisons from the stomach (for corrosive poisons charcoal can be used which will help adsorb the substance and decrease its absorbtion into the GIT)
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| − | *For more information on emetic and anti-emetic drugs click [[Emetics and Anti-Emetic Drugs|here]]
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| − | ===Emetic agents===
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| − | *Drugs cause emesis by irritating the gastric mucosa
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| − | **Histamine
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| − | **ACh
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| − | **Dopamine
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| − | **Catecholamines
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| − | **5-hydroxytryptamine
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| − | **Substance P
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| − | **Enkephalins
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| − | **NK1 receptor agonists
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| − | ===Anti-emetic agents===
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| − | *Anti-emetic agents can be used to treat motion sickness and to treat or prevent vomiting
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| − | **Dopamine (D2) receptor antagonists
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| − | **5-hydroxytryptamine antagonists
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| − | **NK1 receptor antagonists
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| − | **Muscarinic receptor antagonists
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| − | **Histamine (H1) receptor antagonists
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| − | **Gastroprotective agents
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| | ==Species Differences== | | ==Species Differences== |