Digestion
What is the role of PGE2?
Inhibits gastric acid and pepsin and increases mucus and bicarbonate
What is the function of Glucose-6-Phosphatase? (what hormones are involved)
Converts glucose-6-phosphate into glucose during fasting in a process called Glycogenolysis
(glucagon and epinephrine stimulate this)
What physical finding can act as supportive evidence for Primary Tympany upon necropsy? (can you describe it)
Bloat line
(separates pale, bloodless cervical esophagus from congested, dark red thoracic esophagus)
What type of diarrhea results in the separation of apical junctions?
Exudative (mucosal damage - PLE, bloody, mucus)
What could be a consequence of prolonged use of Proton pump inhibitors like Ompeprazole or Histamine-2 antagonists like Cimetidine?
Bacterial overgrowth
What cells help saliva go from isotonic to hypotonic? How?
Ductal cells reabsorb most NaCl from the isotonic fluid and secrete K and HCO3
What is the name of the enzyme that activates trypsinogen to trypsin, which is important for proper protein digestion? (bonus if you can tell me the consequence of a secretin deficiency on this enzyme)
Enteropeptidase
(no secretin = no HCO3 = acidic pH = denatures enteropeptidase = reduced trypsin activation = poor protein digestion)
What viral disease seen in young cattle is caused by Parapoxvirus and known by farmers as “Milkers nodules”?
Bovine papular Stomatitis
Out of the 4 toxins that Clostridium spp. (bacteria) produces, which one is produced by all strains and causes hemolysis?
Alpha toxin
What disorder often affects the wolf and canine teeth of horses and is described as an epithelial-lined, cystic structure in soft tissue including the bone of the jaw?
Dentigerous cysts
What is Chymosin?
Enzyme secreted by young mammals from chief cells that helps slow milk passage, allowing more time for digestion
(replaced by pepsin later)
What 4 hormones inhibit gastric acid? (bonus if you tell me how)
Secretin: inhibit parietal cells and gastrin release
Somatostatin: inhibit parietal cells, gastrin and histamine release
CCK: indirectly suppresses
GIP: inhibits in duodenum and jejunum
A maltese dog comes into the clinic with halitosis, mucosal ulcerations where oral mucosa contacts teeth (Kissing ulcers), and weight loss. The dog is later diagnosed with Chronic Ulcerative Paradental Stomatitis (CUPS). What is the cause of this disorder?
Chronic immune response to bacteria in plaque
A dog presents with both small and large intestinal bowel diarrhea. The owner reports that the diarrhea is watery, but no other symptoms have been noted. What parasite is most likely causing this? Bonus points if you can describe the egg.
Cystoisospora (hard boiled egg)
What enzyme hydrolyzes stored triglycerides (lipolysis)?
Hormone-Sensitive Lipase (HSL)
Why do herbivores need microbial fermentation? (hint* something about structural carbs vs non-structural carbs)
Mammals cannot break down structural carbs (cellulose, hemicellulose, pectin) because they are made of beta-configurations, therefore fermentation is needed
Non-structural carbs (starch, glycogen, simple sugars) are alpha-configurations which mammals produce enzymes capable of breaking these down
What causes the formation of ketone bodies? Name 3 types of Ketone bodies.
Starvation, beta-oxidation generates Acetyl CoA in the liver (mitochondria), excess acetyl-CoA becomes ketone bodies
Acetoacetate, Beta hydroxybutyrate, Acetone
Vagal Indigestion is classified as damage to the vagus nerve anywhere along its length that results in functional outflow problem from the forestomach. What are the 4 types?
(1) Inflammatory lesions = bloat
(2) Failure of omasal transport
(3) Dietary
(4) Pregnancy
A cat comes into the clinic for chronic watery diarrhea, fecal incontinence, and flatulence. Upon further investigation, the issue appears to be coming from the cecum. What parasite is most likely causing this? (Bonus points if you can describe the trophozoite)
Tritrichomonas (purple)
There are 3 phases of vomiting: Prodromal, Retching, and Ejection. If premonitory clinical signs occur during Prodromal, and abdominal muscle contraction occurs during Ejection, what happens in the Retching phase?
Proximal small intestine and gastric antrum contract
Propelling contents into stomach
Gastroesophageal sphincter moves into thoracic cavity
What occurs during the Pharyngeal phase of swallowing? (aka Reflexive Phase)
Touch receptors stimulate Central Pattern Generator (CPG) via glossopharyngeal nerve (CN IX)
Soft palate close and epiglottis folds down
Pharyngeal Constrictors propel bolus to esophagus
Explain the mechanism of peristalsis. Start with the cells of cajal
Cells of cajal create slow waves (pacemaker) which get the muscles ready to contract
When stretch receptors are activated, it causes a slow wave to reach its threshold, opening calcium channels
The influx of calcium causes peristalsis
We learned about Polioencephalomalacia in both DMN pt. 1 and pt. 2, but do you know the pathogenesis of grain overload leading to this Vitamin B1 deficiency?
Grain overload - excess fermentation - increased VFAs and lactic acid - rumen acidosis - decreased good microbiota - overgrowth of bacteria that produce thiaminase enzyme - thiamine deficiency - cerebral necrosis
Enterotoxigenic Escherichia coli (ETEC) produces Heat-labile and Heat-stable enterotoxins. Heat-labile increases cAMP and Heat-stable increases cGMP. How does this lead to diarrhea?
Chloride, Sodium, and water are actively secreted by the CFTR channels on the apical membrane of enterocytes = Hypersecretory/Osmotic diarrhea
Ostertagia spp. (Trichostrongyles) are known for causing anorexia, weight loss, and diarrhea in cattle. Where are the infective L3 found and do they cause small or large bowel diarrhea?
Abomasum
Small intestine
(eggs look like anchlyostoma)