Gastrointestinal Physiology and Pathophysiology Flashcards
In the GI tract, the longitudinal muscle layer contracts in order to shorten the length of the intestinal segment whereas the circular muscle layer contracts to
decrease the diameter of the intestinal lumen. These two layers work together to allow for gut motility. Between these smooth muscle layers is the … plexus, which regulates the gut smooth muscle.
The submucosa contains the … plexus, which transmits information from the epithelium to the enteric and central nervous systems (CNS)
myenteric (Auerbach)
submucosal (Meissner)
In the GI tract, the mucosa is composed of a thin layer of smooth muscle called the muscularis mucosa, which functions to …; the
lamina propria, which contains blood vessels, nerve endings, and immune and inflammatory cells; and the epithelium, which is where the GI contents are sensed and where secretion of enzymes, absorption of nutrients, and excretion of waste products occur
move the villi
In the GI tract, the extrinsic sympathetic nervous system is primarily inhibitory as stimulation can
decrease or cease GI motility. The preganglionic fibers originate at the … segments of the spinal cord.
They travel to the sympathetic chain of ganglia and synapse with postganglionic neurons. Then they travel to the gut where they terminate at the enteric nervous system. The primary
neurotransmitter is norepinephrine.
… also transmits sympathetic signals
T5 to L2
Vasoactive intestinal polypeptide (VIP)
In the GI tract, the extrinsic parasympathetic nervous system is primarily excitatory as it activates GI motility and function. Parasympathetic preganglionic fibers originate in the … region of the spinal cord.
Vagus nerve fibers innervate the …
Pelvic nerve fibers innervate the …
The primary neurotransmitter is acetylcholine.
medulla and sacral
esophagus, stomach, pancreas, small intestine, and the first half of the large intestine
second half of the large intestine, sigmoid,
rectal, and anal regions
The upper esophageal sphincter lies at the level of the cricoid cartilage and is made up of the … muscles. Resting tone ranges from …
mm Hg
cricopharyngeal, inferior constrictor, and circular
esophageal
30–200
The lower esophageal sphincter is formed intrinsically by … muscle and extrinsically by the … muscle. It has both sympathetic and parasympathetic innervation. Resting
tone is … mm Hg
circular esophageal
diaphragm
10–45
Notable cell types in the stomach that aid in digestion are the … cells, which protect against harsh hydrochloric acid; … cells, which secrete hydrochloric acid; … cells, which secrete pepsin; and …, which secrete gastrin
mucous
parietal
chief
G cells
Describe the order that the GI tract recovers from volatile anesthesia
The small intestine is the first part of the GI tract to recover, followed by the stomach (24h) and then the colon (30 - 40h)
Which opioid receptor is associated with the GI effects of opioids?
MU receptors
Is a peripheral mu opioid antagonist and does not cross the blood-brain barrier
Methylnaltrexone
Sympathetic fibers from the upper abdomen, including the liver, stomach, pancreas, small bowel and proximal part of the colon, originates from spinal cord segments …
Those preganglionic fibers terminate in the prevertebral ganglia through splanchnic nerves and generate the …
T5 to L2
Celiac plexus
Sympathetic afferent fibers transmit … pain
Visceral
Which spinal cord segments and nerves are associated with the parasympathetic inervation of the descending colon, sigmoid and rectum?
S2 - S4 via pelvic nerves
ERAS for GI procedures highlights a perioperative regimen with emphasis on:
1- Regional anesthesia
2- Avoidance of opioids
3- Multimodal analgesia
4- Nutrition and preoperative carbohydrates
5- Selective bowel preparation
6- Fluid optimization
7- Temperature control
8- Early removal of tubes and drains
9- Early mobilization
10- Early oral intake
