Term
Gastrointestinal Tract/System
Digestive Tract
Alimentary Canal
The Gut |
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Definition
| what are the 4 names of the GI tract? |
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Term
| mouth, pharynx, esophagus, stomach, small intestine, large intestine |
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Definition
| what makes up the tubular gut? |
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Term
salivary glands
liver
pancreas
gallbladder |
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Definition
| list the accessory digestive organs |
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Term
ingestion
storage
digestion
absorbtion***
excretion
hunger/satiety
defense |
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Definition
| list the functions of the GI tract |
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Term
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Definition
| breaking down macronutrients into forms that can be absorbed |
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Term
1)mucosa: epithelia + lamina propria + muscularis mucosa
2)submucosa
3)muscularis externa: inner circular
4)muscularis externa: outer longitudinal
5) serosa |
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Definition
| list the layers of the tubular gut |
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Term
1) skeletal (voluntary, striated) - mouth, oropharynx, external anal sphincter
2) striated (involuntary) - upper 1/3 of esophagus [has different nerves and regulatory functions]
3) smooth (involuntary) - esophagus, stomach, small intestine, large intestine, biliary and pancreatic ducts, glands |
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Definition
| according to solomon, what are the 3 types of muscle found in the GI tract? where is each found? |
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Term
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Definition
| how a tubular structure moves a mass from point A to point B |
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Term
| the circular layer of muscle contracts behind the bolus and moves down the gut, pushing the food with it. |
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Definition
| how does peristalsis work? |
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Term
primary peristaltic wave all the way down(swallowing)
then secondary peristalsis continues to push what the first wave missed via:
esophageal peristalsis
gastric peristalsis...etc
note: esophageal/gastric can be in the primary wave |
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Definition
| list the types of peristalsis |
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Term
1) regularly spaced
2) isolated
3) irregularly spaced
4) weak regularly spaced |
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Definition
| list the 4 types of intestinal segmentation |
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Term
| to grind, mix, and move food in the stomach |
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Definition
| what is the purpose of gastric peristalsis? |
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Term
1) nerves
2) endocrine hormones
3) paracrine factors |
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Definition
| what 3 systems regulate gut function? |
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Term
1) afferent-gut to brain(sensory)
2) efferent-brain to gut (motor, activation, inhibition)
3) enteric nervous system |
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Definition
| describe the 3 types of gut innervation |
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Term
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Definition
| complex set of neurons in tubular gut & accessory organs |
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Term
enteric nervous system, and/or prevertebral ganglia, spinal cord, brain stem
also sends branches to the submucosal plexus and myenteric plexus |
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Definition
| where do sensory(afferent) neurons from gut epithelium synapse? |
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Term
| stretch(like obstruction), inflammation, nutrients, acid |
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Definition
| what type or stimuli does the afferent innervation carry in the gut? (specific sensory) |
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Term
| 80%, if they don't synapse in the enteric nervous system, they go to the afferent vagus nerve |
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Definition
| what percent of the vagal nerves are afferent? |
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Term
| in celiac and mesenteric ganglia |
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Definition
| where do pre-ganglionic sympathetics to the gut synapse? |
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Term
| splanchnic nerves to enteric nervous system, vasculature, ducts, and parynchyma |
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Definition
| what do post-ganglionic sympathetics (efferent) travel in? |
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Term
| vagal and sacral nerves to the enteric nervous system. |
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Definition
| what do pre-ganglionic parasymathetics to the gut travel in? |
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Term
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Definition
| where do post ganglionic parasymathetic nerve fibers go? |
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Term
BEFORE: sympathetics (in celiac/mesenteric ganglia)
AFTER: parasympathetics |
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Definition
| which efferent fibers synapse BEFORE the enteric nervous system? which synapse AFTER? |
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Term
1)stretching
2)stimulation by Ach
3)stimulation by parasymathetic nerves that secrete Ach at their endings
4) GI hormones |
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Definition
| what factors depolarize the membrane in smooth muscle cells of the gut? |
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Term
1) norepinephrine/epinephrine
2) stimulation of sympathetic nerves with norepi/epi at their endings |
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Definition
| what things hyperpolarize the membrane of smooth muscle cells of the gut? |
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Term
1) outer myenteric plexus (Auerbach's plexus) and
2) the inner submucosal or Meissener's plexus
this spans from the esophagus to the anus |
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Definition
| what plexi make up the enteric nervous system? what region of the body does this span? |
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Term
| sympathetic and parasympathetic innervation |
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Definition
| what influencecs the enteric nervous system? |
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Term
| lots, like 30 or 40 (compare that to just Ach for parasymathetic or epi/norepi of the sympathetics) |
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Definition
| how many post-ganglionic neurotransmitters are there in the enteric nervous system? |
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Term
hormones only act on SPECIFIC receptors
so if a cell has the receptor it responds, if not, it won't |
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Definition
| why don't hormones affect all cells in the gut? |
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Term
the internal/external environment
(the cells "taste" the environment for pH, amino acids, glucose level etc.) |
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Definition
| what do endocrine cells respond to in the gut? |
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Term
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Definition
| in what layer of the gut are endocrine cells found? |
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Term
| ex: gastric secretin only occurs in the stomach |
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Definition
| specific endocrine cells are localized to regions of the gut, give an example of this. |
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Term
4:
CCK, secretin, gastrin, GIP |
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Definition
| how many gut hormones are there? |
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Term
1) gastrin released in presence of amino acids
2) Secretin released in presence of H+
3) CCK released in presence of amino acids and fatty acids
4) GIP released in presence of glucose |
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Definition
| Due to the presence of what specific molecules in the gut cause each of the gut hormones released? |
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Term
1) gastrin released in the stomach
2) secretin released in duodenum near stomach
3)CCK released in proximal small intestine
4) proximal small intestine |
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Definition
| where are each of the gut hormones released? |
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Term
| same as GIP, causes enchanced insulin secretion by the pancreas |
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Definition
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Term
1) g cell stimulated
2) release of gastrin b G cell
3) hormone travels through blood
4) either has beta cell differntiation and regeneration or acts on ECL cell
5) histamine secretion by ECL cell
6) histamine acts on a parietal cell
7) HCl secreted from parietal cell |
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Definition
| describe the path of hormone/endocrine action when a G cell is stimulated. |
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Term
| it has lots of endocrine action which uses the blood stream |
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Definition
| why does the GI tract have such an extensive blood supply? |
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Term
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Definition
| what kind of cells are paracrine cells of the gut similar to? |
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Term
| interstitial fluid, it diffuses to the target |
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Definition
| where do paracrine factors release their transmitter? how does it reach the target cells? |
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Term
1) histamine - secreted by ECL cells, activates acid secretion
2) somatostatin - secreted by D cells, inhibit acid secretion |
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Definition
| what are the 2 paracrine factors of the gut? what cells release them? what do they activate? |
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Term
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Definition
| where does most venous outflow of the gut go? |
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Term
| goes to liver to process toxins, nutrients, hormones and drugs |
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Definition
| where does the portal vein go before it goes to the vena cava, why? |
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Term
| the backflow affects MANY upstream sites |
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Definition
| why is it bad if the portal vein is obstructed? |
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Term
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Definition
| post-prandial means what? |
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Term
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Definition
| there is profound post-prandial ____ to allow motility, secretion, digestion, and absorbtion |
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Term
| acid and cellular metabolism |
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Definition
| local vasoconstriction/dilation reflexes respond to what? |
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Term
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Definition
| release of ___ and ___ cause increased blood flow in microcirculation |
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Term
1) increased tone in gut wall
2) increased intensity of rhythmic contractions
3) increased rate of contraction
4) increased velocity of conduction
also inhibits the pyloric sphincter, controlling emptying of the stomach. and the ileocecal valve which controls emptying of the SI into the cecum |
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Definition
| stimulation of the myenteric plexus causes what 4 things? |
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Term
controls inner wall of each minute segment of the intestine
ex: many sensory signals originate from the GI epithelium and are integrated in the submucosal plexus to help control local intestinal secretion, absorbtion, and contraction of the submucosal muscle |
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Definition
| what does stimulation of the submucosal plexus do? |
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