Vomiting Flashcards
What is vomiting?
- the expulsion of gastric contents and sometimes proximal duodenal contents back into the oral cavity
What is the advantage to vomiting?
- protecting the individual from ingestion of noxious substances
What disorders can vomiting result from?
- GI
- other abdominal conditions
- systemic or metabolic disease
- drug toxicity
Vomiting can have serious consequences what are these?
- volume depletion
- acid-base and electrolyte disturbances
- oesophagitis
- aspiration pneumonia
- malnutrition
What 3 components can vomiting be divided into?
- nausea
- retching
- vomiting
What is nausea?
- precedes retching and vomiting
What are outward signs of nausea?
- depression
-shivering - hiding
- yawning
- lip smacking
- licking
There is often increased salivation and swallowing before vomiting - why is this?
- serves to lubricate the oesophagus and neutralise gastric acid
What causes the reflex of duodenal contents into the stomach?
- reduction in gastric acid and oesophageal motility but increase in proximal small intestine motility
How does retching occur?
- forceful contractions of the abdominal muscles and diaphragm
- this occurs with a closed glottis which produces a negative intrathoracic pressure and positive abdominal pressure
- very forceful expulsion of gastric contents out of the mouth
What do the pressure changes result in during retching?
- result in passage of gastric contents into a dilated oesophagus
What happens when cats retch?
- herniation of the abdominal oesophagus and gastric cardia into the thoracic cavity
Vomiting doesn’t originate from contractions of the gastric muscle - What are the steps involved in the vomiting process?
- deep inspiration and simultaneous closure of the glottis and nasal cavities
- forceful contraction of the abdominal muscles
- large increased pressure in the abdominal cavity which is transferred to contents of the stomach
- cardiac sphincter opens and gastric contents expelled into the oesophagus
- upper oesophageal sphincter opens
- contents expelled through the mouth
Ingesta in the oesophagus doesn’t necessarily result in vomiting - What happens if the upper sphincter remains closed?
- secondary oesophageal peristalsis is triggered by dilation of the oesophagus and the contents is returned to the stomach
What happens of there is high pressure in the stomach?
- the upper sphincter is also opened and vomiting occurs
What is vomiting regulated by?
What is the location of the regulator?
- vomiting is regulated by the vomiting centre
- found within the medulla oblongata of the brain
What can stimulate the vomit centre?
- stimulation is either via humoral pathway initiated by blood borne substances or neural pathways leading to the vomit centre