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11 Cards in this Set
- Front
- Back
Name and define the 4 basic fx of GI sys
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motility
secretion: gastric juices from exocrine gland and hormones from endocrine gland to regulate GI digestion: degrade foods by digestive enzymes absorption |
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List the primary and accessory digestive organs
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Primary: mouth, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, appendix, colon, rectum), anal canal
Accessory organs: salivary glands, exocrine pancreas, biliary sys: gb and liver, endocrine |
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Describe the function of sphincters in the GI system
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pharyngoesophageal sphincter (UES): separates mouth/pharynx and esophagus
gastroesophageal sphincter (LES): separates esophagus and stomach pyloric sphincter/valve: separates stomach and small intestine Sphincter of Oddi: separates pancreas and small intestine ileocecal sphincter/valve: separates small intestine and large intesine internal anal sphincter: involuntary external anal sphincter: voluntary from pelvic nerves keep content in rectum |
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Gastrin
source primary stimulus for secretion function |
G cells of stomach, duodenum
stimulated by protein in stomach, stretch and vagus nerves Fx: stimulates HCl secretion from parietal cells and pepsinogen from chief cells is trophic to stomach and small Int. enhances gastic motility constricts pyloric sphincter to inhibit gastric emptying stimulates ileal motility relaxes ileocecal sphincter > induces colonic mass movement causes gallbladder contraction enhances pancreatic secretion |
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Secretin
source primary stimulus for secretion function |
S cells duodenum jejunum
stimulated by acid in DUODENUM stimulates aqueous NaHCO3 secretion by pancreatic duct cells simtulates aq. NaHCO3 rich bile by liver Inhibits gastric acid secretion is trophic to exocrine pancreas inhibits gastic emptying by increasing pyloric constriction and reduces antral contraction stimulates gastric pepsinogen secretion |
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CCK
source primary stimulus for secretion function |
I cell in duodenum and jejunum
stimulated by fat, protein in duodenum and nerves stimulates digestive enzyme secretion by pancreatic acinar cells (trypsin, chymotrypsin, elastase, carboxypeptidase, aminopeptidase, amylase, lipase) stimulates pancreatic NaHCO3 secretion causes gallbladder contraction inhibits gastric emptying = pyloric constriction is trophic to exocrine pancreas inhibits gastric acid secretion stimulates gastric pepsinogen secretion stimulates bile secretion causes relaxation of shincter of Oddi |
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GIP
source primary stimulus for secretion function |
from K cells in duodenum and jejunum
stimulated by fat, glucose, acid, hypertonicity and distension inhibits gastric acid secretion stimulates insulin secretion by endocrine pancreas inhibits gastric emptying = pyloric constriction |
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State the part of the digestive tract and the primary fx of each
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Mucosa
Epithelium-stratified squamous non-keratinizing or simple columnar with or without a brush border. Lamina Propria- loose areolar connective tissue wiht lymph Muscularis mucosa - thin inner circular, thick outer longitudinal Submucosa dense irreg. conn. tissue with mucous glands and lymph tissue meissner's/submucosal nerve plexus-parasymp for mucosa Muscularis inner circular, outer longitudinal with inner oblique in stomach - has myenteri/Auerbach's plexus - Teniae coli - 3 longitudinal layers Serosa simple squamous mesothelium and adventia of loose conn. tissue blending with surrounding tissue |
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Compare the tubular organs of the digestive tract with respect to the structure of each layer and relate any structural variations to diff in structure
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esophagus is nonkeratinized stratified squamous epithelium
stomach is simple columnar epithelium that secrete mucus. No goblet cells. has rugae when empty small intestine is simple columnar epithelium with brush border, plica circulares/valves of Kerckring, villi, intestinal simple tubular glands called crypts of Lieberkuhn Large intestine is simple columnar absorptive cells with short microvilli many goblet cells and crypts of Liebberkuhn lined by columnar absorptive cells |
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describe the general patters of GI motility
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tonic contractions: sphincters and esophagus
propulsive peristalsis: antrum of stomach, sm. In. and rectum reverse peristalsis: proximal colon MMC: fasting/empty sm. Int. Mass movements: colon Nonpropulsive segmentation: small intestine Haustration: colon |
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explain the sequence of events during swallowing
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oral/voluntary: food bolus moved to pharynx by tongue
pharyngeal: soft palate covers nasopharynx and epiglottis covers glottis to close trachea. UES relaxes. can't breathe during this time Esophageal: peristaltic waves moves food through the esophagus |