Week 4b Gastrointestinal Pathophysiology Flashcards
What is an ileus?
A transient cessation of coordinated bowel motility after surgical intervention,
which prevents effective transit of intestinal contents and/or tolerance of oral
intake
What are 4 factors that can contribute to an ileus?
- Manipulation of the bowel -main factor
- Electrolyte imbalances
- Fluid shifts (too much fluid = swelling of the gut = ↑ ileus)
- Intestinal wall swelling
How long can an ileus last after surgery?
3-4 days
How does surgical manipulation lead to an ileus?
Surgical manipulation increases sympathetic stimulation of the myenteric plexus, which promotes the influx of leukocytes into the “traumatized” areas of the gut and creates inflammatory cascade
What can an untreated ileus lead to and why?
peritonitis, if leaked bacteria cannot be phagocytosed by the body
What can help attenuate ileus incidence?
regional anesthesia
What are the 6 causes of mesenteric ischemia?
- strangulation
- emboli
- aortic X-clamping
- trauma
- atherosclerosis
- inflammation
What are the three treatment steps for mesenteric ischemia?
- reperfusion
- revascularization
- bowel resection
What is the primary function of the colon?
water absorption
Is full colonic resection compatible with life?
yes
What is the primary function of the jejunum?
primary site for digestion & absorption of nutrients
Is jejunal resection compatible with life?
yes, usually the ileum is able to adapt
What is the primary function of the ileum?
absorption of B12 & bile salts
What happens with resection of the ileum?
bile will enter the colon & stimulate fat and water secretion
Why is motor activity disrupted after a bowel anastomosis?
transection of the pacemaker myogenic cells
What part of the anastomosis has disruption in the motor activity?
the distal part of the anastomosis…
must rely on its own intrinsic slow-wave transmission
What nerves innervate the parietal peritoneum, abdominal wall muscles, and skin?
the ventral rami of thoracoabdominal nerves
The ventral rami of the thoracoabdominal nerves innervate:
parietal peritoneum, abdominal wall muscles, and skin
Spinal cord segments T5-L2 innervate __ of the GI tract:
upper abdomen:
- liver
- stomach
- pancreas
- small bowel
- proximal part of the colon
Spinal cord segments T9-L3 innervate ___ of the GI tract:
lower abdomen:
- descending colon
- sigmoid & rectum
- bladder
- lower ureter
Fibers from spinal cord segments S2-S4 innervate:
colon, rectum, internal and external genitalia & bladder
Sympathetic afferent fibers transmit:
visceral pain
Sympathetic efferent nerves:
- inhibit peristalsis
- gastric distention
- GI vasoconstriction
In the GI tract, the parasympathetic nervous system supplies the abdominal viscera via ___-
the vagus nerve