GI Flashcards
Regarding splanchnic nerves, where do the pre-ganglionics synapse in:
Major/minor splanchnic nerves
Lumbar splanchnic nerves
Major/minor splanchnic nerves: Caelico-mesenteric ganglion
Lumbar splanchnic nerves: Caudal mesenteric ganglion
What are the 3 major arteries that branch off the aorta?
What do they supply?
Caeliac=cranial abdominal organs
Cranial mesenteric=mid-abdominal organs
Caudal mesenteric=caudal abdominal organs
What are the 3 major branches that come off the caeliac artery?
Hepatic artery
Left gastric artery
Splenic artery
What are the 3 major branches that come off the cranial mesenteric artery?
Ileo-colic artery
Caudal pancreatico-duodenal artery
Jejunal arteries
What are the 2 major branches that come off the caudal mesenteric artery?
Left colic artery
Cranial rectal artery
What is the benefit of anastomoses?
If an artery gets occluded, the organ will be able to receive blood via a different route
All GI organs drain via which vessel?
Hepatic portal vein
Non-GI organs drain directly where?
Caudal vena cava
Which is the main branch going into the hepatic portal vein?
Gastro-duodenal vein
Where does the left gastric vein drain into?
Splenic vein
Where does the left testicular vein drain into?
Left renal vein
Which lobe of the liver features a renal impression?
Which species doesn’t have this?
Caudate lobe
Pig
In the horse large intestine, what is the purpose of the taenial bands?
Aid in mixing and propulsion
Where is the satiety centre located?
Hypothalamus
What is the difference between probiotics and prebiotics?
Probiotics = sample of normal intestinal microbes Prebiotics = substrates that promote normal intestinal microbes
What value should rumen pH be?
5.5-7
Severe/chronic vomiting leads to loss of what?
HCl
Causes metabolic alkalosis
Other electrolytes lost include Na+, Cl-, K+
Why is it advised to starve a dog/cat if they have a dietary upset disorder?
Reduces gastric secretions
Allows time for mucosal/enterocyte healing
24-48 hours
How does increased dietary fat lead to diarrhoea?
Unabsorbed fat is modified by GI bacteria -> decreased absorption -> hypertonic lumen contents -> water loss from cells by osmosis -> diarrhoea
What is the vomiting centre stimulated by?
Chemoreceptor trigger zone (via dopaminergic input)
GI tract via vagal/sympathetic afferent pathways
Vestibular apparatus via cholinergic/histaminergic afferent pathways
Why would we want to induce vomiting?
If an animal has ingested something toxic
To empty stomach prior to general anaesthetic (as these induce vomiting)
Ideally want to do it within an hour of animal eating, when food is still in stomach
How do antihistamines stop vomiting?
Block histaminergic and cholinergic afferent (input) pathways from vestibular organs to vomiting centre
eg promanthazine
How do anti-cholinergics prevent vomiting?
Block cholinergic afferent pathways from GI tract to vomiting centre
eg propantheline
What are laxatives/cathartics used for?
Relief of acute non-dietary constipation
Removal of toxic ingestants
Prevention of tenesmus (muscle spasm, feeling of constantly needing to poo)
Evacuation of bowel prior to surgery/radiography
How do osmotic cathartics work in easing constipation/ causing diarrhoea?
Non-absorbable therefore osmotically retain water in intestinal lumen
Lactulose metabolised by colonic bacteria into organic acids (lactic, formic, acetic) – increase osmotic pressure
How would you correct rehydration if the patient is vomiting?
Parenterally
What is the epiploic foramen bordered by?
Hepatic portal vein, liver and caudal vena cava
Which nerves make up the abdominal peripheral nervous system?
T13 and L1-L5
