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19 Cards in this Set
- Front
- Back
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What are the two types of motility?
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Segmental and propulsive (peristalsis)
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What is peristalsis?
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Main stimulus distension of GIT
-stretching stimulates enteric nervous system -concentric contraction orad to side and relaxation distal to sute --initiates orad and aborad but orad ceases rapidly Other stimuli can include: -chemical and physical irritation to epithelium -parasympathetic imput Requires intact myenteric plexus |
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What altered motility?
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Decrease in normal propagation of ingesta through GIT
Increased motility initially Decreased motility over time Increased in segmental motility Antiperistalitic waves - can shift fluid up the GIT (orad direction) |
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What are causes of ileus?
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Pain- distension of the GIT, inflammation of peritoneum, unrelated causes of pain
Decreased GIT perfusion Electrolyte abnormalities Endotoxemia |
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What are the types of obstructions?
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Functional
-neurogenic - ileus -vascular - non strangulating infarction Mechanical -extraluminal -intraluminal |
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What are the categories of obstruction?
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Simple - no vascular compromise
Strangulating |
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Treatment for horses with colic
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Xylozine
Alpha -2 agonist - obtund the motility |
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What are the clinical signs of colic?
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Functional or mechanical obstruction similar
Varying degrees of -abdominal distension -tympany -decreased or absent GIT sounds -vomiting -dehydration |
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What are the difference in colic with large and small stongyles?
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Large stongyles = thrombus colic
Small strongyles = vascular colic intusscesuption, encyst and come out at the same time- creating colitis |
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What causes pain in colic?
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GIT origin
-stretch receptors GIT wall - distension/dilatation -tension on mensentery -inflammation - gut wall nociceptors -intestinal ischemia: nociceptors possible from lactic acid -Spasms - somewhat forceful contraction can be associated with pain Peritoneal origin -peritoneal inflammation - peritoneal nociceptors -stimulating of reflexes resulting in decreased motility and thus intestinal distention |
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What are the primary pathophysiologic effects of a simple obstruction?
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Pain
Fluid sequestration and electrolyte abnormalities -into lumen and bowl wall |
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How does intraluminal gas distension occur?
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Associated with gas producing organism- from the large intestinal tract (cecumand large colon)
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What are the effect of motility?
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Stimulation of normal motility
Phase of hypermotility Eventual hypomotility as distension increases |
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What happens when distension increases?
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Local effects: damage to normal wall
Pain and local stimulation of stimulation of spinal reflex sympathetic inhibition of motility Dysfunctional motility: segmental and or antiperistaltic |
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What happens with increase in intraluminal pressure?
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-Isotonic losses
-net secretion as increased intraluminal pressure and local hydrostatic pressure results in depressed absorption and then secretion --3ml/10min (dog) -- 4L/hour (horses) -bowel wall edema -fluid effusion into the abdomen -Decrease in regional blood flow -Shunting from mucosa to muscularis -villus tips show decreased perfusion -0bstruction venous drainage -hypertensive luminal states damage the intestinal epithelium impair viability of GIT |
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How does alteration in the microbial population cause colic?
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Bacterial numbers increase proximal to distal
Overgrowth causes -enterotoxin production -lipid malabsorption -deconjugation bile acids - long chain FA stimulate gut secretion -hydroxylation of dietary FA results in epitheliotoxic metabolites |
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What are the effects of change in bowel motility?
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Pain: distension of GIT, inflammation of peritoneum
Decreaed GIT perfusion Electrolyte abnormalities (decreaed K and Ca) Endotoxemia Drugs |
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What are the effects of changes in bowel wall morphology?
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Edema of mucosa and or bowel wall
Decreased circulation to mucosa Hypoxemia, ischemia to bowel wall |
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What are the results of loss of imbalance of fluids and electrolytes?
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Hypovolemia
-sequestration within the lumen -sequestration within the wall -sequestration within the vasculature Actual loss dues to vomiting and refluxing Significant increase in intraabdominal pressure -Reduced portal circulation -decreased venous return -May have impedance to normal ventilation |
