Shared Flashcard Set

Details

Gastrointestinal Physiology
N/A
148
Physiology
Undergraduate 1
03/08/2015

Additional Physiology Flashcards

 


 

Cards

Term
Neural reflexes involve what system?
Definition
enteric nervous system.
Term
Short reflexes are...
Definition
local reflexes.
Term
All nerves in the GI tract, submucosal and myenteric plexus use...
Definition
short neural reflexes.
Term
Nerves outside the GI tract use...
Definition
long reflexes.
Term
Gastrin...
Definition
increases stomach acid and motility.
Term
Cholecystokinin (CCK)...
Definition
increases enzyme release from pancreas, and gall bladder contraction (bile release).
Term
Secretin...
Definition
increases bicarbonate release from pancreas.
Term
Gastric Inhibitory Peptide (GIP)...
Definition
inhibits stomach acid release and boosts insulin release.
Term
Tonic sphincters...
Definition
upper esophageal, lower esophageal, pyloric, external anal, internal anal, ileocecal, Sphincter of Oddi.
Term
Peristalsis...
Definition
rapid waves of contraction; propels food from esophagus to rectum.
Term
Segmentation...
Definition
mixing action (both directions); slows down movement of food and gradually moves things down.
Term
Basic Electrical Rhythm (BER) is...
Definition
slow wave potentials (spontaneous electrical activity).
Term
BERs are brought closer to threshold by...
Definition
parasympathetics and more contraction.
Term
BERs moved away from threshold by...
Definition
sympathetics and less contraction.
Term
Interstitial Cells of Cajal (ICC)...
Definition
pacemaker cells that initiate slow waves; impulses spread through gap junctions.
Term
Smooth muscle relaxes downstream using what transmitters?
Definition
VIP (vasoactive intestinal peptide), and nitric oxide.
Term
Smooth muscle relaxes upstream using what transmitters?
Definition
acetylcholine, substance P.
Term
Upstream contraction is inhibited by...
Definition
endorphins/opiods.
Term
Migrating Motility Conplexes (MMCs) are...
Definition
waves of peristaltic contractile activity, occuring between meals.
Term
The function of MMCs is...
Definition
to clear the intestines of food.
Term
Colonic motility is...
Definition
slow (2 cm/hr).
Term
Mass Movements...
Definition
drive feces to distal colon.
Term
gastrocolic reflex...
Definition
increases colon motility when food is in the stomach.
Term
The gastroclic reflex is signaled by...
Definition
gastrin and parasympathetics.
Term
Receptive relaxation is...
Definition
stomach stretches without increasing tension.
Term
Pacemaker cells are found where?
Definition
corpus (body).
Term
What occurs when the pyloric sphincter is tonically contracted?
Definition
retropulsion (food pushed back into corpus).
Term
GERD (gastroesophageal reflux disease; heartburn) is caused by what?
Definition
poor tone in th LES.
Term
What is a bezoar?
Definition
something indigestible by the stomach.
Term
Gastric emptying is promoted by what?
Definition
gastric distension and fluidity of chyme.
Term
The gastric phase is signaled by what?
Definition
gastrin and the vagus nerve (parasympathetic).
Term
Gastric motility is inhibited by what?
Definition
intestinal distension, fat, acid, and hypertonicity.
Term
What is dumping syndrome?
Definition
rapid movement of high-osmolarity chyme out of the stomach, leading to increased fluid secretion and decreaed blood pressure.
Term
The duodenal phase is signaled by what?
Definition
autonomic nerves (short and long), and entergastrones (secretin, CCK, GIP).
Term
What are the functions of entergastrones?
Definition
slow stomach emptying or acid production.
Term
Stress and fear do what to gastric emptying?
Definition
decrease due to sympathetic inhibition.
Term
Lipids...
Definition
diffuse across the epithelium.
Term
Water-soluble molecules require what?
Definition
a transporter.
Term
How does water move between cells?
Definition
tight junctions.
Term
What is the main source of digestive enzymes?
Definition
pancreas.
Term
What can pancreatitis produce?
Definition
maldigestion.
Term
Surface area is increased by what?
Definition
folds, villi, and microvilli.
Term
What is Celiac disease?
Definition
gluten (wheat) allergy affecting the upper intestine (decreases surface area).
Term
What is Crohn's disease?
Definition
inflammation in the lower small intestine (decreases surface area).
Term
Where are new enterocytes formed?
Definition
crypts.
Term
What is the lifespan of an average enterocyte?
Definition
3-5 days.
Term
Enterocyte replacement is inhibited by what?
Definition
radiation and chemotherapy.
Term
Increased acid can cause what?
Definition
maldigestion.
Term
Carbohydrates must be absorbed as what?
Definition
monosaccharides (glucose (dextrose), galactose and fructose).
Term
Disaccharides include what?
Definition
maltose, actose and sucrose.
Term
Polysaccharides are...
Definition
glucose polymers.
Term
Starch makes up what percentage of dietary carbohydrates?
Definition
60%
Term
Amylose and amylopectin are both what?
Definition
starches.
Term
Cellulose is...
Definition
indigestible.
Term
Amylase is released from what?
Definition
salivary glands and the pancreas.
Term
What is the funciton of amylase?
Definition
breaks down starch and produces maltose, maltriose and alpha-limit dextrin.
Term
Where are brush border enzymes located?
Definition
membrane surface.
Term
What are dextrins?
Definition
starches broken down into side chains that can't be broken down further.
Term
Isomaltae breaks down alpha-limit dextrin to what?
Definition
glucose.
Term
A lactase deficiency is characterized by what?
Definition
osmotic diarrhea due to undigested lactose reaching the colon.
Term
Bacterial digestion of lactose produces what?
Definition
hydrogen gas.
Term
Glucose and galactose enter the enterocyte by...
Definition
Na+/glucose co-transporters (SGLTs).
Term
The driving force of monosaccharide transport is...
Definition
Na+ gradient.
Term
Glucose uptake stimulates...
Definition
sodium and water uptake.
Term
Fructose doesn't require what?
Definition
sodium.
Term
Before absorption, proteins must be broken down into what?
Definition
amino acids, and di/tripeptides.
Term
Proteases cut through what?
Definition
big proteins.
Term
Peptidases cut through what?
Definition
small peptides.
Term
What condition does pepsin require?
Definition
acidic.
Term
Pepsin release is stimulated by what?
Definition
vagus nerve or gastrin.
Term
Pepsin is released from where?
Definition
stomach chief cells.
Term
Pepsin is secreted as what?
Definition
pepsinogen.
Term
Pepsin is hydrolyzed by what?
Definition
acid to form active pepsin.
Term
Trypsin, chymotrypsin and elastase are released from where?
Definition
the pancreas by CCK and vagal nerve.
Term
Trypsin, chymotrypsin and elastase are secreted as what?
Definition
trypsinogen, chymotrypsinogen, and proelastase.
Term
Trypsin, chymotrypsin and elastase are converted to their active form by what?
Definition
enteropeptidases (brush border enzymes).
Term
Aminopeptidases are located where?
Definition
brush border and intracellular.
Term
What is the funciton of aminopeptidases?
Definition
cut single amino acids from ends of peptides.
Term
Amino acids transporters are located where?
Definition
brush border enzymes.
Term
The driving force of amino acid transport is what?
Definition
Na+ gradient.
Term
Peptide transporters are located where?
Definition
brush border membrane.
Term
Di/tripeptides are co-transported with what?
Definition
H+.
Term
Lipids include what?
Definition
triglycerides and cholesterol.
Term
Fats are emulsified by bile salts/acids to form what?
Definition
micelles.
Term
Bile acids are formed where?
Definition
the liver.
Term
Bile acids are made form what?
Definition
cholesterol.
Term
Bile salts are...
Definition
bile acids conjugated with taurine or glycine.
Term
Bile salts are more what than bile acids?
Definition
water soluble.
Term
Bile contains what?
Definition
bile salts, cholesterol, and bilirubin.
Term
What is bilirubin?
Definition
a pigment formed in the liver from hemoglobin breakdown.
Term
What is jaundice?
Definition
excess bile pigments in plasma.
Term
Jaundice can be caused by what?
Definition
bile duct bloackage (cholestasis).
Term
Where is bile stored?
Definition
gall bladder.
Term
Gall bladder contraction is stimulated by what?
Definition
CCK.
Term
Gallstones occur if...
Definition
bile becomes insoluble.
Term
Lipase is used for what?
Definition
enzyme digestion.
Term
Lipase is released from where?
Definition
the pancreas.
Term
Lipase release is triggered by CCK in response to what?
Definition
fat or protein in the intestines.
Term
Triglycerides are digested into what?
Definition
fatty acids and 2-monoglycerides.
Term
Fat is absorbed through...
Definition
passive diffusion.
Term
Chylomicrons are formed by...
Definition
adding apolipoproteins to reformed triglycerides.
Term
Fat exits the cell by what?
Definition
exocytosis.
Term
What is fat transported into?
Definition
lacteals (lymphatic vessels).
Term
Bile salts are...
Definition
not absorbed with fat.
Term
Bile salts are only absorbed in...
Definition
the ileum.
Term
Malabsorption (Crohn's disease) causes what?
Definition
colonic irritation and fluid secretion (diarrhea).
Term
Water-soluble vitamins are...
Definition
B, C and folate.
Term
Water-soluble vitamins are absorbed by what?
Definition
transporters (small intestine).
Term
B12 (cyanocobolamin) is absorbed from...
Definition
the ileum.
Term
B12 absorption requires what?
Definition
intrinsic factor from parietal cells.
Term
Dietary sources of B12 include...
Definition
eggs, milk and meat.
Term
What is pernicious anemia?
Definition
lack of intrinsic factor; B12 deficiency.
Term
What are symptoms of pernicious anemia?
Definition
impairs RB formation and nerve health.
Term
Fat soluble enzymes (A,D,E and K) are absorbed by what?
Definition
passive diffusion.
Term
What are the functions of gastric acid?
Definition
activates pepsinogen, breaks down connective tissue in diet, and kills micro organisms.
Term
What organism is resistant to gastric acid?
Definition
H. pylori.
Term
H. pylori survives by making what?
Definition
urease.
Term
The survival of H. pylori causes what?
Definition
peptic ulcers caused by inflammation.
Term
Where is acid produced?
Definition
parietal cells.
Term
H+ is formed from H2O+CO2 using what?
Definition
carbonic anhydrase.
Term
H+ is pumped into the lumen by what?
Definition
H+/K+-ATPase (proton pump).
Term
Acetylcholine is released by what?
Definition
parasympathetic nerves.
Term
Stimuli for acetylcholine release include what?
Definition
sight and smell of food (central), and protein in the stomach (local).
Term
Histamine is an intermediary released by what?
Definition
enterochromaffin-like (ECL) cells.
Term
Stimuli for histamine release include what?
Definition
ACh and gastrin.
Term
Gastrin is released by what?
Definition
G cells in the gastic antrum.
Term
Stimuli for gastrin release include what?
Definition
protein, distension, and ACh.
Term
Hormone inhibitors are called what?
Definition
enterogastrones.
Term
Enterogastrones include:
Definition
secretin (stimulus: acid), GIP & CCK (stimuli: fatty acids, peptides).
Term
What is the role of tight junctions?
Definition
make mucosa impermeable to H+.
Term
Mucus is secreted by what?
Definition
surface and neck cells.
Term
Bicarbonate is secreted by what?
Definition
surface and epithelial cells.
Term
What are the actions of prostaglandins?
Definition
decrease acid secretion, stimulate fluid secretion and enhance cytoprotective properties (cell protection).
Term
Prostaglandins are inhibited by what?
Definition
asprin and NSAIDs (advil, motrin, etc.).
Term
Exocrine secretions...
Definition
enter ducts.
Term
Pancreatic enzymes are secreted from what?
Definition
acinar cells, stimulated by CCK.
Term
What is the function of pancreatic bicarbonate secretion?
Definition
neutralizes stomach acid.
Term
Bicarbonate is secreted from what?
Definition
duct cells, stimulated by secretin.
Term
H+ and HCO3- are formed by...
Definition
carbonic anhydrase.
Term
H+ is pumped out on the basolateral side by what?
Definition
Na+/H+ exchanger.
Term
Chloride is secreted into the lumen by what?
Definition
CFTR.
Term
A Cystic Fibrosis defect causes:
Definition
reduced fluid secretion, and more mucus formation.
Term
CFTR stands for what?
Definition
Cystic Fibrosis Transmembrane Regulator.
Term
Function of villi:
Definition
absorption.
Term
Function of crypts:
Definition
secretion.
Term
Sodium enters the enteroctye with what?
Definition
glucose, amino acids and H+.
Term
A Na+/K+/2Cl- carrier is used in secretion on what side?
Definition
basolateral.
Term
The role of cAMP is to...
Definition
keep CFTR open.
Supporting users have an ad free experience!