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Physiology GI Dr T
Physiology GI Dr T
179
Physiology
Graduate
04/22/2011

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Term
Gland cells release their secretory product into ducts which open onto an epithelial surface of the body
Definition
Exocrine secretion
Term
Hormone released into the blood stream to act on a distant cell
Definition
Endocrine secretion
Term
Hormone synthesized in a neuron released in the blood to act on a distant cell
Definition
Neurocrine secretion
Term
Hormone released from a cell, diffuses a short distance in the interstitial fluid to act on a neighboring cell
Definition
Paracrine secretion
Term
Substance released into a synaptic cleft to act on a nearby cell
Definition
Neurotransmitter secretion
Term
Substance that stimulates secretion from a cell
Definition
Secretagogue
Term
Largest of the salivary glands
Definition
Parotid gland
Term
Contains purely serous glands
Definition
Parotid gland
Term
Watery secretion containing amylase but not mucins
Definition
Parotid gland
Term
Mixed glands
Definition
Submandibular and Sublingual glands
Term
Secrete more viscous saliva containing mucins and amylase
Definition
Submandibular and Sublingual glands
Term
Lubricates food for easy swallowing
Definition
Function of saliva (mucins)
Term
Begins digestion of starch
Definition
Function of saliva (amylase)
Term
Solubilizes material so that is can be tasted
Definition
Function of saliva
Term
Cleans mouth and teeth
Definition
Function of saliva (Lysozyme, SIgA)
Term
Dry mouth occurring in people with no or decreased salivary gland function
Definition
Xerostomia
Term
Facilitates speaking
Definition
Function of saliva
Term
Helps clear esophagus of refluxed gastric secretion
Definition
Function of saliva
Term
Metabolism and blood flow of salivary glands is proportional to ____
Definition
Rate of saliva formation
Term
Organic components of saliva (proteins from acinar cells)
Definition
Amylase, Lipase, Mucus glycoproteins, Proline-rich glycoproteins, Tyrosine-rich protein, Histidine-rich protein, Peroxidase
Term
Organic components of saliva (proteins from non acinar cells)
Definition
Lysozyme, SIgA, growth factos-gastric mucosa, Regulatory peptides-vasodilation
Term
Ionic composition of saliva with increased flow rate
Definition
K decreases slightly almost independent of flow rate
Term
Ionic composition of saliva with increased flow rate
Definition
Na, HCO3, CL all increase
Term
Ionic composition of saliva with increased flow rate
Definition
pH Increases approaching 8
Term
Ionic composition of saliva with increased flow rate
Definition
Saliva becomes less hypotonic
Term
Two-stage model of salivary secretion (primary secretion isotonic)
Definition
Na, K, Cl levels are close to plasma
Term
Two-stage model of salivary secretion (primary secretion isotonic)
Definition
Amylase concentration and rate of fluid secretion depend on type of stimulation
Term
Two-stage model of salivary secretion (excretory ducts modifying secretion)
Definition
Remove Na, Cl
Term
Two-stage model of salivary secretion (excretory ducts modifying secretion)
Definition
Add K, HCO3
Term
Two-stage model of salivary secretion (excretory ducts modifying secretion)
Definition
Saliva becomes more hypotonic because rate of Na, Cl absorption is greater than K, HCO3 secretion
Term
Two-stage model of salivary secretion (excretory ducts modifying secretion)
Definition
Little H2O is absorbed in the ducts because of low H2O permeability
Term
Primary physiologic control of salivary secretion
Definition
PNS
Term
Elicits a copious, sustained flow of watery, amylase-containing saliva
Definition
PNS
Term
Causes vasodilation increasing blood flow to salivary glands
Definition
PNS
Term
Produces atrophy of salivary glands
Definition
Parasympathectomy
Term
Elicits a low volume, short duration flow of viscous saliva high in amylase content
Definition
SNS
Term
Initially causes vasoconstriction causing reduced blood flow to salivary glands
Definition
SNS
Term
Causes no major defect in salivary gland function
Definition
Sympathectomy
Term
SNS input to salivary gland
Definition
Postganglionics from superior cervical ganglion
Term
PNS input to salivary glands
Definition
Preganglionics from CN 7,9 which synapse on postganglionics of submandibular and otic ganglion
Term
Elevation of intracellular cAMP effect on salivary secretion
Definition
Activation of B-receptors (B1)>Results in low volume secretion rich in amylase
Term
Elevation of intracellular Ca effect on salivary secretion
Definition
Activation of ACh (M2 receptors)>Results in large volume secretion by stimulating both protein and electrolyte secretion
Term
Secrete mucus and HCO3, protect surface from mechanical injury
Definition
Columnar cells of gastric mucosa
Term
Opening of a duct into which one or more glands secrete, very numerous walls contains cell which secrete gastric juice
Definition
Gastric pits
Term
Secreted by parietal cells
Definition
HCl
Term
Kills ingested bacteria
Definition
HCl
Term
Activates pepsinogen
Definition
HCl
Term
Enhances iron absorption
Definition
HCl
Term
Releases free cobalamins (Vit B12) for absorption
Definition
HCl
Term
Secreted by parietal cells along with HCl but by a different mechanism
Definition
Intrinsic factor
Term
Only gastric secretion required to maintain life
Definition
Intrinsic factor
Term
Secreted by chief cells (peptic cells)
Definition
Pepsinogens
Term
Cleaved into pepsin which begins digestion of proteins
Definition
Pepsinogens
Term
Secreted by G cells
Definition
Gastrin
Term
Stimulates gastric acid secretion
Definition
Gastrin
Term
Secreted by columnar cells of the stomach
Definition
Mucus and HCO3
Term
Helps protect stomach from chemical and mechanical damage
Definition
Mucus and HCO3
Term
At low (basal) secretory rates of salts and H20
Definition
Na>H
Term
At all secretory rates of salts and H2O
Definition
K>plasma, vomiting leads to hypokalemia
Term
At high rates secretory rates of salts and water
Definition
Lumen of stomach approaches isotonic HCl
Term
At high secretory rates of salts and H2O
Definition
Venous blood from stomach becomes alkaline, called alkaline tide
Term
Narrow region in cardiac portion, contains primarily mucus secreting cells
Definition
Cardiac glandular region
Term
Mucus secreting cells, parietal cells, chief cells
Definition
Oxyntic (acid secreting) glandular region (body or corpus of stomach)
Term
Predominance of mucus secreting cells, G cells, D cells
Definition
Pyloric glandular region (antrum)
Term
Few or any parietal or chief cells
Definition
Pyloric glandular region (antrum)
Term
Secretagogues neurotransmitter at the parietal cell level
Definition
ACh
Term
Released from PNS and intrinsic regulation of gastric acid secretion
Definition
ACh
Term
Increase acid secretion of parietal cells through M3 receptor
Definition
ACh
Term
Secretagogues paracrine regulator of gastric acid secretion
Definition
Histamine
Term
From ECL cells in gastric mucosa near parietal cells
Definition
Histamine
Term
Stimulates acid secretion through H2 receptors
Definition
Histamine
Term
Action blocked by cimetidine
Definition
Histamine
Term
Action blocked by atropine
Definition
ACh
Term
Secretagogues hormonal regulator of gastric acid secretion
Definition
Gastrin
Term
From G cells in antrum and duodenum
Definition
Gastrin
Term
Also acts indirectly by releasing histamine from ECL cells
Definition
Gastrin
Term
Trophic effect on the growth and maintenance of the oxyntic region of the stomach and intestines
Definition
Gastrin
Term
Inhibitor of gastric acid secretion released from D cells in body and antrum
Definition
Somatostatin
Term
Inhibitor of gastric acid secretion
Definition
Prostaglandins
Term
Inhibitor of gastric acid secretion
Definition
Epidermal growth factor
Term
Phase of increased gastric acid secretion stimulated by sight, smell, and taste
Definition
Cephalic
Term
Phase of increased gastric acid secretion, reflex action mediated entirely by vagus and intramural plexuses to directly stimulate parietal cells and indirectly stimulate G and ECL cells
Definition
Cephalic
Term
Phase of decreased gastric acid secretion when pH<3 stimulates D cells to release somatostatin: acting as a hormone parietal cells and paracrine on G cells
Definition
Cephalic
Term
Phase of increased gastric acid secretion by presence of food in stomach
Definition
Gastric
Term
Phase of increased gastric acid secretion by distention of stomach leading to central (vagovago) and local (enteric) response to directly stimulate parietal cells and indirectly stimulate G and ECL cells
Definition
Gastric
Term
Phase of increased gastric acid secretion when AA (tryptophan, phenylalanine) bind G cells stimulating release of gastrin
Definition
Gastric
Term
Greatest amount of gastric acid occurs in this phase where HCl is pumped across apical membrane of parietal cells and HCO3 out the basolateral membrane entering the blood causing alkaline tide
Definition
Gastric
Term
Phase of gastric acid secretion where a pH<3 blocks acid secretion induced by distention (duodenal ulcers inhibit this reflex)
Definition
Gastric
Term
Patients with ulcers should not take antacids of milk products containing _____ because it is a secretagogues to gastric acid
Definition
Ca
Term
This secretagogue is a phosphodiesterase inhibitor preventing destruction of cAMP
Definition
Caffine
Term
Secretagogue to gastric acid secretion
Definition
Coffee
Term
In high concentrations this is a secretagogue to gastric acid secretion
Definition
Alcohol
Term
Phase of gastric acid secretion brought about by presence of chyme in duodenum results first in stimulation than inhibition
Definition
Intestinal
Term
Proenzyme cleaved in the presence of acid to form pepsin
Definition
Pepsinogen
Term
Main stimulus for pepsin release is activation of
Definition
Vagal cholinergics
Term
Low gastric pH triggers local cholinergic reflexes that stimulate ____ secretion
Definition
Pepsinogen
Term
Gastrin is a weak secretagogue for ___ cells in humans to release pepsinogen
Definition
Chief
Term
Tumors in duodenum or non beta cell portion of the pancreas produce high circulating levels of gastrin
Definition
Zollinger-Ellison syndrome (gastrinoma)
Term
High levels of circulating ___ have a trophic effect that leads to increased number of parietal and ECL cells
Definition
Gastrin
Term
High levels of circulating ___ produce a constant stimulation of acid secretion which cause fulminant peptic ulceration, diarrhea, steatorrhea, hypokalemia, and eventual erosion of bowel
Definition
Gastrin
Term
Secrete alkaline mucus that protects the duodenum from acid
Definition
Brunners glands of duodenum
Term
Ducts of these glands empty in crypts of lieberkuhn which are found through the small and large intestine
Definition
Brunners glands of duodenum
Term
Intermixed with columnar epithelial cells, secrete mucus
Definition
Goblet cells of small intestine
Term
Elaborate and secrete a watery secretion, rate of secretion is slightly less than absorption
Definition
Epithelial cells of small intestine
Term
Numerous goblet cells, volume of secretion is less than small intestine, but richer in mucus, aqueous portion is alkaline due to secretion of HCO3
Definition
Colon
Term
Gland secretion: hydrolysis protein, digestion of starch, breakdown of lipids into monoglycerides and FFA
Definition
Exocrine Pancrease
Term
Gland secretion: Neutralization of gastric acid in duodenum, maintenance of proper pH for digestion
Definition
Exocrine Pancrease
Term
Aqueous component of pancreatic juice, concentration varies depending on secretory rate
Definition
HCO3
Term
Aqueous component of pancreatic juice, concentration varies inversely with HCO3
Definition
Cl
Term
Aqueous component of pancreatic juice, concentration is about the same as plasma
Definition
Na, K
Term
Increases HCO3 volume of aqueous component of pancreatic juice
Definition
Secretin
Term
Elaborated and secreted by epithelial cells that line ducts of pancreas
Definition
Aqueous component
Term
Elaborated and secreted from acinar cells of pancreas
Definition
Enzymatic component
Term
Enzymatic component of pancreatic juice that digests starch
Definition
Amylase
Term
Enzymatic component of pancreatic juice that breakdown fats
Definition
Lipases
Term
Enzymatic component of pancreatic juice that hydrolyze proteins
Definition
Proteases
Term
Secreted as a proenzyme this protease can activate chymotrypsinogen, procarboxypeptidase, and trypsinogen once activated by enterokinase
Definition
Trypsin
Term
Enzymatic component of pancreatic juice, DNAase, RNAase
Definition
Nucleases
Term
Controlled by both hormonal and nervous influences
Definition
Secretory activity of acinar and duct cells of exocrine pancreas
Term
Electrolyte and enzyme secretion from pancreas are controlled ____
Definition
Separately
Term
Phase of vagal stimulation of both acinar and duct cells of pancreas
Definition
Cephalic
Term
Phase where pancreatic juice has low volume high enzyme content because Ach has a greater effect on enzyme secretion than fluid secretion
Definition
Cephalic
Term
Phase where pancreatic juice has high volume low enzyme content, stimulated by vago vago reflex due to distention of stomach
Definition
Gastric
Term
Phase of pancreatic secretion due to presence of acids, peptides, and fatty acids in duodenum
Definition
Intestinal
Term
Presence of acid in duodenum causes ____ release from ___ cells of the small intestine
Definition
Secretin, S
Term
This pancreatic juice phase contains copious secretion of HCO3 rich low enzyme secretion
Definition
Intestinal
Term
Fatty acid and AA (phenylalanine, valine, methionine) in duodenum cause ___ release from ___ cells of the small intestine
Definition
CCK, I
Term
Phase of pancreatic secretion high in enzymes
Definition
Intestinal
Term
Potent secretagogue of enzyme secretion but little effect on aqueous secretion
Definition
CCK
Term
Stimulates aqueous secretion but little effect on enzymatic secretion
Definition
Secretin
Term
Markedly potentiates the effects of secretin
Definition
CCK
Term
Principal digestive function is to secrete bile
Definition
Liver
Term
Regulation of metabolism, protein synthesis, store certain vit A,D,B12, degradation and metabolism of certain hormones
Definition
Liver
Term
Metabolism and excretion of some drugs and toxins (bilirubin, heavy metals, steroids, fat-soluble vit
Definition
Liver
Term
Principal source of cholesterol and major site of cholesterol secretion
Definition
Liver
Term
Required for normal fat digestion and absorption
Definition
Bile
Term
Provides sole excretory route for many substances not excreted by the kidney
Definition
Bile
Term
In humans, the most important route for elimination of cholesterol is its conversion to ____ and excretion in the feces
Definition
Bile acids
Term
Contents include: bile acids, cholesterol, lecithin (phosphatidylcholine), bile pigments (bilirubin)
Definition
Bile
Term
Produced by a breakdown of Hg
Definition
Bilirubin
Term
Emulsify lipids allowing greater access of lipase for digestion
Definition
Bile acids
Term
____ and lipids form micelles that are absorbed by intestinal epithelium
Definition
Bile acids
Term
Bile acids, cholesterol, phosphatidylcholine, and bilirubin are actively secreted in _____
Definition
Bile canaliculi
Term
____ and ____ are osmotically drawn into canaliculi
Definition
Water, plasma cations
Term
Other plasma solutes that enter bile passively are _____and ____
Definition
Glucose, AA
Term
As bile moves out of the canaliculi into the smallest bile ducts, these ducts are lined with columnar epithelial cells called
Definition
Cholangiocytes
Term
Tight junctions between cholangiocytes are permeable to ____ making the bile quickly isotonic
Definition
H2O
Term
Cholangiocytes secrete ____ into the ducts
Definition
HCO3
Term
Cholangiocyte secretion increase the ___ and ___ of ductal bile, but decrease bile ___ concentration
Definition
Volume, pH, salt
Term
Stimulates HCO3 rich secretion of cholangiocytes
Definition
Secretin
Term
Stimulates HCO3 rich secretion of cholangiocytes
Definition
Glucagon
Term
Stimulates HCO3 rich secretion of cholangiocytes
Definition
VIP
Term
Inhibits HCO3 rich secretion of cholangiocytes
Definition
Somatostatin
Term
Cholangiocyte stimulant hormones stimulate ___ which stimulates the opening of the CFTR channels and activation Cl-HCO3 exchanger
Definition
cAMP
Term
Cholangiocyte stimulant hormones stimulate insertion of ___ increasing water permeability of the apical membrane
Definition
Aquaporins
Term
___ inhibits secretion of cholangiocytes by decreasing ___ levels
Definition
Somatostatin, cAMP
Term
Glucose and AA that passively leaked into bile are actively taken up by ____
Definition
Cholangiocytes
Term
Between meals ~1/2 the bile is stored here, the other 1/2 remains in liver bile ducts "hepatic bile"
Definition
Gallbladder
Term
During interdigestive periods, this is constricted forcing bile into the gallbladder
Definition
Sphincter of oddi
Term
Absorbs Na,Cl,HCO3 and concentrates bile 5-20X
Definition
Gallbladder
Term
Small amounts of bile are passively absorbed along the entire small intestine and colon but the bulk of bile uptake occurs through active absorption here
Definition
Terminal ileum
Term
Absorbed bile enters hepatic portal circulation where ___ take up bile and re-secrete it into bile canaliculi
Definition
Hepatocytes
Term
What happens to bile acids that are not absorbed
Definition
Secreted in feces
Term
Entire bile pool is recirculated how many times during a typical meal
Definition
Twice
Term
During this phase of digestion intermittent contractions of gallbladder force bile into partially relaxed sphincter of oddi
Definition
Cephalic
Term
During this phase of digestion intermittent contractions of gallbladder force bile into partially relaxed sphincter of oddi
Definition
Gastric
Term
During cephalic and gastric phases of digestion contraction of gallbladder and relaxation of sphincter of oddi are mediated by
Definition
Vagus
Term
During this phase highest rate of gall bladder emptying occurs
Definition
Intestinal
Term
During the intestinal phase strongest stimulus for gallbladder emptying is
Definition
CCK
Term
Released by duodenal I cells in response to fat and protein
Definition
CCK
Term
During intestinal phase this reaches the gallbladder via circulation causing strong contraction of gall bladder myoepithelium and relaxation of sphincter of oddi
Definition
CCK
Term
What is the major factor influencing bile acid secretion and synthesis
Definition
Bile acid concentration in hepatic portal blood
Term
Presence of bile acids in hepatic portal blood ___ bile acid secretion (choleretic effect)
Definition
Stimulate
Term
Presence of bile acids in hepatic portal blood ___ bile acid synthesis
Definition
Inhibit
Term
Low concentration of bile acids in hepatic portal blood ___ synthesis of bile acids
Definition
Increase
Term
Low concentration of bile acids in hepatic portal blood ___ bile acid secretion
Definition
Decrease
Term
Released from duodenum in response to acid
Definition
Secretin
Term
Stimulates cholangiocytes to release greater volume of HCO3 rich fluid but does not stimulate bile secretion from hepatocytes
Definition
Secretin
Term
Does not participate in the control of bile secretion from hepatocytes
Definition
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