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48 Cards in this Set
- Front
- Back
- 3rd side (hint)
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functions of salivary secretion
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lubrication,
solvation for taste antibacterial (lysozyme, lactoferrin & IgA) amylase |
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quantity of saliva produced daily
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1/2 to 1 l/day
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function of amylase
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hydrolyzes alpha 1-4 bonds of glucose (amylose=starch, resembles glycogen)
digest amylopectin, glycogen & amylose |
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concentration characteristics of saliva during slow flow
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high K (so water reabsorbed)
secondary saliva-more processed |
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concentration characteristics of saliva during high flow
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like plasma:
primary saliva- (not very processed) Na (high) Cl HCO3 K (very little) |
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saliva secretion at acinar cells
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K, HCO3, H20, Na, Cl
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location of saliva transporters
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duct cells
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transporters and saliva processing
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in duct cells
Increase K in lumen resorb Na & Cl |
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components of gastric secretions
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HCL
Pepsinogen Mucus Intrinsic Factor (gastrin is endocrine) |
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parietal cell secretes
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HCL & Intrinsic Factor
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G cell secretes
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Gastrin (inhibited by somatostatin)
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D cell secretes
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Somatostatin (inhibited by gastrin)
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enteroendocrine cells in the stomach
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G cell - gastrin
D cell- somatostatin |
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transporters in HCL secretion
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K/H pump at lumen sends K into cell (drives CA to increase HCO3)
HCO3 out/Cl in then electrochem gradient drives Cl into lumen |
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regulation of HCL secretion
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gastrin increases
somatostatin decreases |
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stimulation of parietal cell
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gastrin, ACh & Histimine
gastrin- G cell senses peptides, rls gastrin, acts on ECL AND parietal, (stronger signal than histimine) Vagus stims ECL and Pariatel- get ACh stim and histimine histimine & CCK from vagal stim ACh |
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where does histamine stimulus in stomach come from
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ECL
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mechanism of stimulation of parietal cells
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Gastrin & ACh stim Ca rls
Histimine stims Adenylyl Cyclase |
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product of D cell
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releases somatostatin- provides negative feedback to proton pump
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action of somatostatin
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produced in D cell
when pH 2.5 or less binds R on ECL to block hist rls binds G cell to block gastrin rls |
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secretion of pepsinogen
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secreted by Cheif cells
(stimulated by peptides) activated by HCL and pepsin |
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mucus secretion
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from goblet cells
80% carbohydrate inhibits pepsin from approaching epithelials mucus production inhibited by NSAIDs |
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Intrinsic Factor Secretion
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made & secreted by parietals
necessary for B-12 absorption (makes complex) secreted with gastrin |
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stimulation of parietal cell
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gastrin, ACh & Histimine
gastrin- G cell senses peptides, rls gastrin, acts on ECL AND parietal, (stronger signal than histimine) Vagus stims ECL and Pariatel- get ACh stim and histimine histimine & CCK from vagal stim ACh |
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where does histamine stimulus in stomach come from
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ECL
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mechanism of stimulation of parietal cells
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Gastrin & ACh stim Ca rls
Histimine stims Adenylyl Cyclase |
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product of D cell
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releases somatostatin- provides negative feedback to proton pump
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action of somatostatin
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produced in D cell
when pH 2.5 or less binds R on ECL to block hist rls binds G cell to block gastrin rls |
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secretion of pepsinogen
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secreted by Cheif cells
(stimulated by peptides) activated by HCL and pepsin |
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mucus secretion
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from goblet cells
80% carbohydrate inhibits pepsin from approaching epithelials mucus production inhibited by NSAIDs |
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Intrinsic Factor Secretion
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made & secreted by parietals
necessary for B-12 absorption (makes complex) secreted with gastrin |
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Secretions of the pancreas
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HCO3
enzymes |
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pancreatic enzymes
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Amylase
Tripsin, Chymotrypsin, Carboxypeptidase, Elastase- zymogens Lipase-colipase PLA2 Cholesterol esterase-nonspecific lipase |
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stimulation of pancreatic secretion of HCO3
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S cells sense H+ (pH> 4)
secrete secretin increase HCO3 via cAMP on Ducts |
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secretory cells of pancreas
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Acinars- secrete enzymes
Ducts- secrete HCO3 |
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stimulation of pancreatic secretion of enzymes
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I cells
sense aa's, peptides & FA's secrete CCK increase enzyme rls via IP3 on acinars |
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anatomical features of colon
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no villi
haustra taeniae coli cecum, ascending, transverse, descending, sigmoid, rectum |
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water absorption in small & large intestine
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98% is reabsorbed
85% in SI 13% in LI |
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mechanism of water resorption
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osmotic gradient- passive
Na/K ATPase at BL draws Na in from lumen drives CA rxn, HCO3 out/Cl in Na & Cl increase in tissue H2O follows |
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fluid input to GI
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2 L food & drink
2 L gastric secretions 1.5 L (each) saliva, pancreas, intestines .5 L bile |
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fluid absorption in gut
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7.5 L SI
1.4 L LI .1 L excreted in feces |
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mechanism of cholera toxin
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constituatively activates CFTR--reverses osmotic potential
covalent modification of alpha subunit of GPCR prevents GTP hydrolysis (to GDP) |
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effects of aging on digestive system
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compromised nutrition
neural coordination biochem (less enzyme/hormone, decreased sensitivity) diminished vascular supply |
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inflammatory polyps associated with...
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ulcerative colitis
IBD |
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adenoma colon polyps association with CA
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>2cm, 50% are cancerous
<1 cm, 1% are cancerous glandular in origin |
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polypoid carcinoma characteristics
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malignant
originate from epis |
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colorectal cancer stages
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I: submucosa
II: circ or long muscle III: 1-4 lymph nodes IV: metastasis |
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characteristics of diverticula
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associated with age
herniation of colon wall 95% are in sigmoid areas of vascular penetration cause weakness bleeding from mechanical damage bacteria collect |
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