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Structure
Gastric pits
Gastric glands- ducts produce subst go through gastric pits -> lumen
- Cell -> enz & acid- covered by mucous- so not digested

Stomach
03 April 2017

18:08

Functions
V
...
down of food
• Subst chem b
...
down fats)
• Protect against bact and toxins - gastric acid , neutralise them
• Produce intrinsic factor for intestinal absorption of vit B12 - intrinsic only produced by stomach, can’t absorb vit
B12 unless attached to it- w/out get pernishious anaemia & r
...
c be abnormal -potentially fatal
• Reservoir for storage food & regulated input to duodenum
• Regulation appetite via stretch of stomach & ghrelin - appetite hormone- when stomach empty
...
(fundic region of stomach) Of lower oesophageal sphincter &
gastric distention
Mixing and retropulsion
- Mix food mat w/ gastric secretions -> chyme- liquid in stomach
- Gastric slow waves sweep from pacemaker region toward pylorus
- Retropulsion against closed pyloric sphincter
- Excitatory: acetylcholine (vagus), gastrin
- Inhibitory: symp nerves

New Section 1 Page 2

Gastric emptying
* Movement chyme -> duodenum at controlled rate - can't cope w/ too much food
* Changes in sphincter tone- regulate tone
* Rate dependent on food composition & vol
* Inhibitory: CCK, secretin, GIP, enterogastric reflexes -fatty food stays longer in
stomach- activate cck
Migrating myoelectric comples (MMC)
 Wave of electrical act from 4-5 hrs after last meal
 Mediated by motilin release from upper intestines- activates electrical wave
 Movement air & fluid through stomach & intestines
 House-keeping mechanism- clear debris & prevent colonic bact entering ileum- create
one direction movement of what's left over
 Borborygmus
- Rumbling/ gurgling noise made by movement fluid & gas in intestines - sweep bact
back -> large intestine



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