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Chapter 28: Stomach and small intestine - Coggle Diagram
Chapter 28: Stomach and small intestine
Gastric motility & emptying
receptive relaxation
Vagal mediated
triggered by movement in pharynx and esophagus
peristaltic waves- BER gastric
sweep to pyloris
Antral systole
3-4 times per min
gastric emptying
antrum, pylorus and upper deodenum function as unit
prevention of regurg- stim of CCK and secretin by pyloric sphincter
Regulation of gastric motility
rate of emptying depends on type of food
carbs- few hours
prot slower, fat slowest
also depends on osmotic pressure of material entering duodenum
hyperosmolality in deodenum- decrease gastric emptying
neural in onset
fats, carbs & acid in duodenum inh gastric acid and pepsin and emptying
via neural and hormonal mechanisms
Peptide YY, CCK
vomiting
central regulation of gut motility
reverse peristalsis
glottis closes preventing aspiration
breath held mid inspiration
abdominal contracts, chest held in fixed position
abdominal pressure increase, LES relax
vomiting center- reticular formation of medulla
p474
Triggers of vomiting
irritation of mucosa of UGIT
impulses relayed to medulla- visceral afferent symp pathway
central causes
vestibular nuclei
motion sickness
emotional responce
diencephalon and limbic system
chemoreceptors in medulla
chemoreceptor trigger zone- are postrema
circumventricular organs
not blood brain barrier
effected by drugs
radiation sickness
dopamine D2 recpetors 5-HT3 receptors
Serotonin from enterochromaffin in small intestine
Intestinal motility