Lecture 21 - Alimentary Two Flashcards
Describe the distribution of visceral afferent innervation:
Visceral afferent fibres travel with sympathetic and paasympathetic nerves
What afferent receptors pick up extreme stretch and chemo nociception and what is the pathway to the brain?
Primary afferent C fibres and travel via the spinothalamic pathway to the brain
Where are the stretch receptors located?
- In muscular layers of hollow viscera between muscularis and mucosa/submucosa 2. Serosa of solid organs 3. In mesentery especially associated with large vessels
Where are the chemoreceptors located?
Respond to variety of chemical stimuli. Located in the mucosa and submucosa of hollow viscera
State the four ways stretch receptors are activated and provide an example of each:
- Distention of hollow viscous - GIT obstruction 2. Forceful muscular contractions - parturition 3. Stretching of solid organ serosa or capsule - hepatic congestion or pancreatitis 4. Stretching of mesentry or mesenteric vessels - e.g. neoplasia
What are the two cases in which chemical receptors are activated? Provide an example of each:
- Inflammation - GIT obstruction of ulceration 2. Tissue ischemia or necrosis - GDV
What are the three different types of obstruction?
- Simple obstruction 2. Closed loop obstruction 3. Strangulation obstruction
Name the intestinal obstruction that is shown below and then state:
- Type of nociceptor that is activated
- Possible sequalae
Phytobezoar
- Stretch nociceptor
- Build up to intestinal fluid proximal to the lesion and pressure necrosis of the mucosa in contact with the bezoar
Provide an examples of two types of closed loop obstruction and state the type of nociceptor that is activated in each case:
- External - ulcerated umbilical hernia and internal - incarceration of small intestine through the epiploic foramen
- In both of these cases the nociceptors are activated by stretch and chemicals
What are the two different types of strangulation obstructions shown below?
Top - volvulus
Bottom - torsion around a pedunculated lipoma
What is the name of the condition that is shown below?
540 degree gastric torsion
What is the name of the condition that is shown below?
Caecal torsion
What is the name of the condition that is shown below?
Left Displaced abomasum (cows )
What is the name of the condition that is shown below?
Gastric dilation volvulus - GDV (dogs)
Name the condition that is shown in the cow below:
Right-sided abomasal torsion (cows)m
What is a paralytic ileus?
What could be a cause?
What type of nociceptor is activated?
- Failure of intestinal contents to be propelled aborally
- Gastrointestinal surgery - inadequate decompression of the gut
- Can be associated with electrolyte imbalanced (e.g. endurance horses), peritonitis and toxaemia
What is the name of the condition shown below in the colon of the horse? What is the cause of it? What are some potential sequaelae?
- Vascular bowel disease
- Associated due to migrating stages of S.vulgaris
- In severe cases, this causes segmental infarcts of colonic wall
Fill in the blanks in the diagram below:
How do clinical signs that are associated with abdominal pain vary between species?
Marked species differences in manifestation of abdominal pain - signs are more severe when both stretch and chemicals activate nociceptors. Signs are more obvious in horses and less obvious in ruminants
What are the signs seen in abdominal pain in dogs?
Depression, licking abdomen, whining, growling, snapping to less conspicous (tense abdomen, grunting, trying to walk away when palpated)
What are the clinical signs seen in abdominal pain in catttle?
Kicking the abdomen, positive grunt test
What are the clinical signs seen in acute abdominal pain in horses (colic)?
- Agitated appearance
- Grinding teeth
- Constantely looking at flank
- Sweating
- Not eating
- Lying in lateral recumbency
Why is there failure to pass gas and faeces in GI obstruction?
Associated with:
- Emptying of intestine distal to obstruction
- Reflex reduction in intestinal motility
What is reduced/absent intestinal borborygmi typically associated with?
- Distention of intestine with fluid and gas
- Reflex neural inhibition
- Reduced blood supply
- Hypovolaemia, acid-base and electrolyte disturbances
- Endotoxaemia
