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Cell Bio Accessory Organs of Digestion
KYCOM Block 3
117
Biochemistry
Graduate
11/02/2012

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Cards

Term
what is the large intestine covered by
Definition
thin connective tissue (glisson's capsule) that is thicker at the hilum
Term
what exit at the hilum
Definition
lymphatics
Term
what enters at the hilum
Definition
portal vein, heptatic a
Term
what are the functions of the liver
Definition
makes plasma proteins, storest and converts vitamins and iron, degrades toxins and drugs
Term
what plasma proteins does the liver make
Definition
labumin, lipoproteins, fibrinogen, clotting proteins, alpha and beta globuins
Term
what vitamins does the liver store and convert
Definition
vitamin A, vitamin d, vitamin K
Term
what does the liver do the drugs and toxins
Definition
converts them to more soluble forms
Term
what glucose metabolic pathways is the liver involved in
Definition
glycogen synthesis, glycogenolysis, glycolysis
Term
what lipid metabolic pathways is the liver involved in
Definition
beta oxidation of FA, ketone body synthesis, cholesterol
Term
what cholesterol compounds does the liver have a role in
Definition
bile salts, VLDL, organells
Term
what role does the liver have in amino acid metabolism
Definition
non-essential amino acid synthesis, urea synthesis
Term
what are the exocrine functions of the liver
Definition
phospholipids, cholesterol, bile salts
Term
what are the functions of bile
Definition
aid in absorption of lipids from the intestine, dispose of conjugated and degraded waste products
Term
what are the endocrine functions of the liver
Definition
modify structure and function of many hormones
Term
what hormones does the liver modify
Definition
vitamin D, thyroxine, growth hormone, insulin, glucagon
Term
describe the dual blood supply of the liver
Definition
venous (portal) supply via hepatic portal vein and arterial supply via hepatic artery
Term
how much of the blood supply to the liver is venous portal blood
Definition
75%
Term
where does venous portal blood come from
Definition
intestines, pancreas, spleen
Term
what does the venous portal blood carry to the liver
Definition
nutrients and toxic materials absorbed in the intestines, blood cells and breakdown products of blood cells from the spleen, endocrine secretions from the pancreas and enteroendocrine cells of the GI tract
Term
where does the venous and arterial blood of the liver mix
Definition
before perfusing the hepatocytes
Term
what are the components of the liver in regard to structural organization
Definition
parenchyma, connective tissue stroma, sinusoidal capillaries, perisinusoidal spaces
Term
what is the parenchyma
Definition
organized plates of hepatocytes
Term
what is the connective tissue stroma continous with
Definition
fibrous capsule
Term
what is within the connective tissue stroma of the liver
Definition
blood vessels, nerves, lymphatic vessels, bile ducts
Term
what are sinusoidal capillaries (hepatic sinudoids)
Definition
vascular channels between plates of hepatocytes
Term
where are perisinusoidal spaces (spaces of Disse)
Definition
between sinusoidal endothelium and hepatocytes
Term
what are the thiree ways to describe the structure of the liver
Definition
classic lobule, portal lobule, liver acinus
Term
what is the classic lobule based on
Definition
distribution of branches of the portal vein and heptaic artery and the path of blood flowing through hepatocytes
Term
what is the main component of hte classic lobule
Definition
stacks of anastomosing plates of hepatocytes seperated by sinusoidal capillaries
Term
what is in the center of the classic lobule
Definition
terminal hepatic venule (central vein)
Term
what are around the edges of the classic lobule
Definition
portal areas of canals containing portal triads
Term
what does the portal lobule emphasize
Definition
exocrine function of the liver, bile production and secretion
Term
what is the portal lobule shaped like
Definition
triangle
Term
what is in the center of the portal lobule
Definition
bile duct, portal area
Term
what are around the corners of the portal lobule
Definition
central vein / terminal hepatic venule
Term
how does bile flow in the portal lobule
Definition
within hepatic plates to the bild duct in the portal area
Term
what is the liver acinus
Definition
structural unit that gives best correlation between blood perfusion, metabolic activity, and liver pathology
Term
describe the shape of the liver acinus
Definition
short axis extends between two adjacent portal areas, long axis extends between two terminal hepatic venules
Term
what is zonation, where does it occur
Definition
in the liver acinus zonation describes the interpertation of patterns of degeneration, regeneration, and specific toxic effects
Term
what is the benifits of being in zone 1
Definition
first to recieve oxygen, nutrients, and toxins from the blood
Term
what are the risks of being in zone 1
Definition
first to show effects of bile duct obstruction
Term
what are the benifits of being in zone 3
Definition
last to respond dto toxins and bile stasis
Term
what are the risks of being in zone 3
Definition
first to show effects of reduced perfusion
Term
other than avability to nutrients, what else is different between the zones
Definition
variation of enzyme activity and number and size of organelles and size of glycogen deposits across zones
Term
what type of capillaries are the hepatic sinusoids
Definition
discontinous endothelium
Term
what makes the heptaic sinusoids so leaky
Definition
large fenestrae without diaphragms within the endothelium, large gaps between neighbopring endothelial cells, discontinous lamina absent over large areas
Term
what are kupuffer cells
Definition
stellate sinusoidal macrophages that are a part of hepatic sinusoid lining
Term
where is the perisinusoidal space
Definition
between basal surfaces of the hepatocytes and basal surfaces of the endothelial and kupuffer cells that line sinusoids
Term
what occurs in the perisinusoidal space
Definition
exchange of materials between blood and liver cells
Term
describe the significant barrier between blood plasma and hepatocytes
Definition
there is none
Term
in the fetal liver what is located in the perisinusoidal space
Definition
islands of blood forming cells
Term
what cells are in the perisinusoidal space
Definition
blood forming in fetus, hepatic stellate cells (Ito cells)
Term
what do Ito cells do
Definition
store hepatic vitamin A withing cytoplasmic lipid droplets
Term
what happens to Ito cells in pathologic conditions
Definition
they loose their lipid and vitamin A storage capability and differentiate into myofibroblasts, seem to play a role in hepatic fibrogenesis resulting in liver fibrosis
Term
where does plasma from perisinusoidal space drain into
Definition
periportal area into small area called space of Mall
Term
where does the fluid in the space of Mall go
Definition
lymphatic capillaries in the portal canals
Term
where does a major portion of thoracic duct lymph come from
Definition
liver
Term
what is the only thing that stays in the sinusoidal capillaries, what leaks into the perisinosal space
Definition
cells stay in plasma leaks out
Term
describe the normal turn over rate of hepatocytes
Definition
slow
Term
describe the turn over rate for hepatocytes when killed by toxins, disease, or surgery
Definition
faster
Term
what are the prodominate organells of hepatocytes
Definition
RER, golgi, SER, lysosomes, peroxisomes
Term
what does the SER of a hepatocyte do
Definition
oxidation, methlyation, and conjugation required for inactivation and detoxification of various substances before excretion
Term
what do peroxisomes of hepatocytes fo
Definition
oxidation of FA, breakdown of purines, synthesis of cholesterol, bile acids, some myelin lipids
Term
what is a bile caniculus, formed by, location
Definition
a small canal formed by apposed groves in the surface of adjavent hepatocytes
Term
describe the flow of bile ina hepatocytes
Definition
flows from region of central vein to portal canal
Term
what do hepatocytes secrete bile into
Definition
canliculi
Term
what is a intrahepatic ductule
Definition
near portal canals bile canaliculi join to form interhepatic ductules (canals of Hering)
Term
what partially lines canals of Hering
Definition
hepatocytes and cholangiocytes
Term
where do interhepatic ductules drain into
Definition
interlobular bile ducts in portal canals
Term
what do interlobular bile ducts of portal canals lead to
Definition
extrahepatic bile ducts that deliver bile to the gall bladder and duodenum
Term
what are the cells of the gallbladder mucosa
Definition
somple columnar epithelium
Term
what does the gallbladder wall have a layer of
Definition
smoother m
Term
describe the mucosa texture of the gallbladder, what special feature does this have histologically
Definition
mucosa has folds and the epithelial cells have many mitochondria
Term
what is the main function of the gallbladder
Definition
store bile, concentrate it, and release it when necessary to the digestive tract
Term
what induces contraction of the gallbladder
Definition
CCK
Term
what releases CCK
Definition
enteroendocrine cells of small intestine
Term
what stimulates CCK release
Definition
presence of dietary fats in small intestine
Term
what does the pancreas produce in general
Definition
digestive enzymes, hormones
Term
where is the exocrine portion of the pancreas located
Definition
through out the organ
Term
where is the endocrine portion of the pancreas located
Definition
in masses called islets of langerhans dispersed through out the organ
Term
hat kind of gland is the exocrine glands of the pancreas
Definition
compound acinar serous
Term
describe the serous cells of the exocrine pancreas
Definition
highly polarized with spherical nucleus, typical protein secreting cells
Term
what do acinar cells of the exocrine pancreas store and release
Definition
proenzymes
Term
describe the number of zygomen granules in the exocrine pancreas
Definition
varies with digestive phase
Term
what do pancreas exocrine acini empty into
Definition
intercalated ducts
Term
what is the function of the initial portion of the intercalated ducts of exocrine pancreas
Definition
penetrate lumen of acini and are made of centroacinal cells which are the interacinal portion of hte intercalated duct
Term
what are intercalated ducts tributaries of
Definition
intralobular ducts
Term
what are interlobular ducts lined with, where
Definition
columnar epithelium within connective tissue septum
Term
what are the exocrine products of the pancreas
Definition
proteolytic enzymes, amylase, lipases, nucleases
Term
what proteolytc enzymes does th epancreas make
Definition
trypsin, chymotrypsin
Term
where are proenzymes activated
Definition
in lumen of small intestines after secretion
Term
where are proenzymes stored
Definition
secretory granules of acinar cells
Term
what does enterokinase do
Definition
cleave trypsinogen to form trypsin
Term
what does trypsin do
Definition
activates proteolytic enzymes 9not enterokinase) in cascade
Term
what protects the pancreas from active enzymes
Definition
trypsin needs to be activated to activate other enzymes, protease inhibitors made by acinal cells
Term
what is pancreatic secretion controlled by
Definition
secretin and CCK
Term
what makes secretin and CCK
Definition
enteroendocrine cells of intestinal mucosa in duodenum and jejunum
Term
what stimulates secretin release
Definition
gastric acid, low pH in intestinal lumen
Term
what does secretin do
Definition
causes duct cells to secrete large volume of fluid that is rich in barcobinate but has little or noenzyme content that neutralizes acid which allows pancreatic enzymes to function at optiomal ph
Term
what triggers CCK release
Definition
long chain FA, gastric acid, some AA in intestinal lumen
Term
what does CCK do
Definition
causes acinar cells to secrete proenzymes
Term
together, what do secretin and CCK do
Definition
cause secretion of large volume of protein rich alkaline pancreatic fluid
Term
what do the islets of langerhands consist of
Definition
cords of polygonal cells invested in a network of fenestrated capillaries
Term
what are the major islets of langerhans cell types
Definition
B, A, D
Term
where are B cells located
Definition
central endocrine pancreas
Term
which is the most abundent islet of langerhan cells
Definition
B cells
Term
what do B cells secrete
Definition
insulin
Term
where are A cells located
Definition
peripherial endocrine pancreas
Term
what do A cells secrete
Definition
glucagon
Term
where are D cells located
Definition
peripherial endocrine pancreas
Term
what do D cells secrete
Definition
somatostatin
Term
what are the minor cells of endocrine pancrease
Definition
PP, D-1, EC cells
Term
what do PP cells secrete
Definition
pancreatic polypeptide
Term
what do D-1 cells secrete
Definition
vasoactive intestinal peptide (VIP)
Term
what do EC cells secrete
Definition
secretin, motilin, substance P
Term
what is the major function of the endocrine pancreas
Definition
regulate blood glucose
Term
what does somatostatin do
Definition
inhibits insulin and glucagon
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