Term
| Absorptive Columnar Cells |
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Definition
Have Microvilli
immature golgi, mitochondria
For absorbing |
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Term
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Definition
Produce enzymes to breakdown food
Well developed ER and Golgi
Zymogen granules containing enzymes released to lumen via exocytosis |
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Term
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Definition
Amine Precursor Uptake Decarboxylase
Produce and release peptide hormones into blood stream
Endocrine cells including G, I, S, D Cells
A - Lots of amines
PU - Uptakes many hormonal precursors
D - lots of decarboxylase enzyme to convert precursors into amines |
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Term
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Definition
Contain and release mucus granules for intestinal surface
Mucus is carb rich |
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Term
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Definition
| Stem cell for other intestinal epithelial cell |
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Term
| Parasympathetic activation of GI |
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Definition
Increased Activity
Increased blood flow etc. |
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Term
| Sympathetic activation of GI |
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Definition
decreased activity
decreased blood flow etc. |
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Term
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Definition
Secreted by G cells
Stimulates acid secretions
Stimulates gastric mucosal growth
Works on CCK-B Receptors (enterochromaffin & oxyntic cells) - less on CCK-A receptors (D Cells)
Inhibited by Somatostatin
Stimulated by GRP, Vagal innervation |
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Term
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Definition
Cholecystokinin
Secreted by I cells
release is inhibited by bile acids
Duodenum and Jejunum
Contracts the gallblader (bile acid release) (most potent stimulus for contraction)
Inhibits stomach contraction - relaxation of sphincter of oddi
Acts on CCK-A (smooth muscle and gallbladder)
competes with gastrin for CCK-B - inhibits acid secretion |
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Term
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Definition
Secreted by S cells in response to increase in acidity Duodenum Pancreatic bicarbonate secretion Massive increase in response by presence of phenylalanine
Binding to VIP R ->activation, cAMP production, increased enzymatic release |
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Term
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Definition
Upper duodenum during fasting
Increases motility
Stimulates Interdigestive myoelectric complexes |
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Term
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Definition
G cell secretes gastrin to blood Gastrin activates CCK-B receptors on Oxyntin Cells to secrete H+ into lumen and indirectly through enterochromaffin cells via histamine.
Activates pepsinogen secretion by chief cells |
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Term
| Nucleus of the Solitary Tract |
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Definition
Point of convergence of taste chemoreceptor afferents
Origin of salivary glad stimulating efferents
Parotid via S |
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Term
| Parotid gland stimulation |
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Definition
| Nucleus of the Solitary Tract -> (Inferior) Salivary nucleus->Glossopharyngeal nerve (integration of taste) -> Otic ganglion |
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Term
| Submandibular and sublingual gland stimulation |
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Definition
| Nucleus of the Solitary Tract -> Superior Salivary Ganglion -> chorda tympani (integration of taste) -> submandibular ganglion -> Lingual nerve |
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Term
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Definition
Released by stomach parietal cells
Promotes absorption of B12 in the ileum |
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Term
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Definition
4 Transfers. 1 out apical, 2 in apical. 2 out lumenal 1 in lumenal
Circulating CO2 is brought in and turned into H2CO3 in presence of carbonic anhydrase with H20. Dissociation turns it into H+ and HCO3-. HCO3- is sent into the circulation in exchange for Cl-. H+ is exchanged into the lumen for K+ (K+/H+ ATPase) coupled to a lumenal Cl- exuding channel.
Apical: CO2 and Cl- in, HCO3- out
Lumenal: H+ Cl- out, K+ in
Also: IF secretion
High mitochondrial function |
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Term
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Definition
=Peptic Cell
Gastric secretion of Pepsinogen
Zymogenic |
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Term
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Definition
Release somatostatin in response to low lumenal pH
Slows release of gastrin |
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Term
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Definition
Inhibits gastrin release on G cells
Activates G protein coupled ST R (somatostatin receptor) |
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Term
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Definition
BAKED
Lipid soluble vitamins
B12
A
K
E
D |
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Term
| Cephalic Phase of Digestion |
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Definition
External Stimuli
Vagal innervation
Ach on muscarinic receptors
G Cells -> Gastrin -> Oxyntic Cells -> H+ Secretion
G Cells -> Gastrin -> Chief Cells -> Pepsinogen
ECL -> Histamine -> H2 Receptor on Oxyntic -> H+
Oxyntic -> H+
low pH and Pepsinogen |
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Term
| Gastric Phase of Digestion |
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Definition
Mechanical contact with peptides of G cells and distention
Release of Gastrin ->->->Oxyntic cells->H+
Lower pH-> D Cells -> somatostatin -> G Cells -> reduced gastrin |
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Term
| Intestinal Phase of Digestion |
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Definition
H+ will activate S cells to make and release secretin which will cause pancreas to release HCO3- and enzymes acting on VIP R via cAMP dep. pathway
Metabolites will act on I cells to cause release of HCO3- from gallbladder and pancreas and enzymes via CCK-A and a Ca dep. pathway
CCK will bind competitively with gastrin to CCK-B in the stomach to stop H+ secretion |
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Term
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Definition
Exocrine Function
- Bicarbonate to buffer acids to maintain pH for optimal enzymatic function, prevent denaturation.
- Maintaining pH to promote micelle formation
- digestive enzymes (amylases)
- Protect intestinal mucosa against acid
- Glandular portion
Endocrine Function
- Insulin
- Glucagon
- islets of langerhans
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Term
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Definition
Exocrine
Acinar - enzymes
middle portion - thinner epithelium, bicarbonate production
duct cells - HCO3-/Cl- exchange |
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Term
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Definition
Gastroferrin released by oxyntic cells
Iron binding protein which binds iron and absorbs in ileum |
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Term
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Definition
Na K HCO3 Mg Ca
similar to blood
very high HCO3-
Neutralizes chyme to reach optimal pH for micelle and enzymes |
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Term
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Definition
At rest CFTR (Cystic fibrosis transporter regulators) are aggregated on the lumenal side.
Activation by secretin causes disaggregation
H+ transporters in vesicles are deposited on the apical membrane
H+ will be pumped into the blood, HCO3- out to lumen and Cl- (lumen) and CO2 (Blood) are taken into cell |
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Term
Pancreatic Enzymes
(Classes, Activation, Location, Release) |
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Definition
Lipase
Amylase
Protease
(deoxy/)Ribonuclease
Elastase
Activated by:
Trypsin
Enterokinase
pH
Made by ER, Golgi Released as a zymogen granule into the acinar portion of the lumen |
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Term
| Central Regulation of Energy Balance |
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Definition
Hedonic System - Pleasure of eating. Controlled by VTA
Homeostatic System - Energy stores are low. Hypothalamus and brainstem |
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Term
| Hypothalamus in food intake |
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Definition
| Lesions caused obesity (PVN, VMN, DMN) or weight loss (LHA) |
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Term
| Ventricular system in food intake |
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Definition
| CSF compartment where signal proteins are released from circulation |
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Term
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Definition
| POMC and NPY/AgRP try to find balance of activation of MC3/4R (Melanocortin) neuron |
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Term
| Lateral Hypothalamic Area (LHA) |
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Definition
Negative control centre
Lesion caused reduced food intake and weight loss |
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Term
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Definition
Hormone
from Adipocytes
Leptin causes decrease in appetite when bound to LepR
As people get larger, leptin increases. Eventually become leptin resistant
Activates POMC
Inhibits NPY/AgRP
Acts on GABAergic neurons to reduce food intake |
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Term
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Definition
Anorexic neurons
Stimulation leads to reduced food intake
On Hypothalamic ARC
Activated by Leptin |
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Term
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Definition
Orexigenic neurons
Stimulation leads to increased food intake
On Hypothalamic ARC
Inhibited by leptin
Activated by Ghrellin
Colocalized neurons |
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Term
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Definition
Released from GI
Orexigenic
Activates NPY/AgRP |
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Term
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Definition
forms common bile duct after joining with cystic duct and joins pancreatic duct to empty into duodenum at sphincter of oddi
fed by left and right hepatic ducts |
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Term
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Definition
| Secreted in bile from gallbladder reabsorbed in ileum and recycled by the liber |
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Term
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Definition
Breakdown of Heme from RBCs
Hepatocytes remove the iron by hemeoxygenase
made from biliverdin by biliverdin reductase
Conjugated to glucoronic acid in the liber
secreted to the intestines by bile ducts and gallbladder
Bilirubin is resorbed in the intestin
Conjugated bilirubin is not very lipid soluble - it is negatively charged |
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Term
| Prehepatic or Hemolytic unconjugated bilirubin |
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Definition
anaemia causing jaundice, increased production of unconjugated bilirubin
dark urine and feces |
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Term
| Intrahepatic or Hepatocellular uncojugated bilirubin |
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Definition
Damage to liver
Feces are pale, liver is not producing enough bilirubin |
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Term
| Posthepatic or Obstructive conjugated bilirubin |
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Definition
| Blockage in duct urine is dark and feces is pale from under excretion of bile |
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Term
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Definition
Bilirubin is taken up unconjugated in the intestines returned through the portal blood to the liver where it is conjugated to make bilirubin glucuronide.
It is secreted into the intestine at the sphincter of oddi by the common bile duct, via the gall bladder.
After it is unconjugated and reduced it forms urobilinogen which either gets taken back up into the liver where it can be turned back into bilirubin or excreted in the urine or it is oxidized into stercobilinogen in the intestine which then gets excreted in the feces. |
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Term
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Definition
| transport vessels formed by adjacent hepatocyte membranes |
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Term
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Definition
Canalicular Multi-organic anion transporter
transports anions
uses electric gradient
transports bilirubin |
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Term
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Definition
Stores and concentrates bile
Contains lipid peroxidases and induces micelle formation
Can pump using the pressure of the sphincter of oddi
Has muscle to contract and rugae to stretch
Gallbladder bile is more concentrated and has less bicarbonate than hepatic bile
Lecithin, cholesterol and bile salts are concentrated |
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Term
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Definition
Absorb bile salts oxygen and nutrients
Conjugate bile salts and secrete to canaliculi
Gluconeogenesis
Glycogen deposition
Oxydation
Neutralizing of toxins |
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Term
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Definition
Primary Bile acids
Phosphatidyl choline - lipid metabolism
Cholesterol |
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Term
| Migrating myoelectric Complex (MMC) |
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Definition
Cycles of contractions
Spontaneous and triggered by foood
Triggered by motilin |
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Term
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Definition
Sodium Dependant Glucose transporter
Type 1 is in intestinal wall
2 Na for 1 Glucose |
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Term
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Definition
Pure glucose transporters
Differing affinities for glucose and fructose |
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Term
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Definition
Proximal colon - vagus nerve
descending colon and down - Pudendal Nerve (Parasympathetic) |
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