Digestive System Flashcards
mouth
- mechanical (chewing) + chemcial (salivary amylase) digestion begins
- saliva lubricates food into bolus for esophagus –> increase salivary amylase
salivary amylase (SA)
digests startch into maltose
pharynx
- food enters and separates from respiratory system
- epiglottis: prevents choking by blocking the trachea
esophagus
- peristalsis: wave-like contraction of muscles pushes food down towards stomach
- upper 1/3: voluntary and skeletal muscle
- middle 1/3: smooth muscle
- lower 1/3: mixed
stomach
- enters via cardiac sphincter
- converts and mixes food into chyme (mechanical churning and chemical enzyme digestion)
- lined with gastric pits leading to gastric glands
G cells
stimulated by food distinction and secretes gastrin
what stimulates parietal cells to secrete HCl?
gastrin
parietal cells
secrete HCl
chief cells
secrete gastric lipase and pepsinogen –> low pH converts to pepsin
G cells stimulate…
chief cells
mucous cells
secretes mucus for lubrication, protection against stomach acid
small intestine
90% of digestion and nutrient absorption
parts of small intestine
DJ Eye
* dudodenum, jejunum, ileum
where does acidic chyme enter
via the pyloric sphincter
goblet cells
secret mucus and protect from acidic environment
acid
stimulates release of secretin which stimulates release of bicarbonate ions into duodenum via pancreatic duct
acidic chyme moves via
peristalsis
what stimulates the release of CCK
proteins and fats will stimulate SI to release CCK
CCK
slows gastric emptying
* stimulates pancrease to release digestive enzymes to do most of the digestion (macro–> oligo)
* stimulates gallbladder to relase bile into duodenum
villi
- finger like projections on the wall
- made of enterocytes
microvili
projections of villi and increase SA and absorption efficiency
lacteal
each villus is associated with a capillary network and a lymph vessel
microvilli form?
brush border in which final digestion takes place (oligo –> mono)
gastrin
- produced by G cells of stomach
- stimulate parietal cells to create gastric juice
- stimulate chief cells to release pepsinogen and lipase
secretin
- produced by duodenum
- stimulate pancreas to release bicarbonate to neutralize acidic chyme
CCK
- produced by duodenum
- stimulate gallbladder to release bile
- stimulate pancrease to release digestive enzyme (trypsin)