Flashcards in Pancreas, Liver, and Gallbladder Deck (34):
secrete onto a surface by acinus cells
secrete into vasculature
epithelial and non-epithelial cells
what are the three types of exocrine glands
1. merocrine-salivary glands, pancreas (exocytosis)
2. holocrine- sebaceous glands (secrete disintegrated cells)
3. Apocrine (secrete large micelles) mammary glands
the pancreas endocrine function and exocrine function
endocrine: islets of langerhans, protein and poly. peptides hormones (insulin and glucagon)
exocrine: acinar cells (release digestive molecules into the duodenum aka enzymes)
the exocrine pancreas
acinar cells exocytose zymogen granules into intercalated ducts
zymogen granule enzymes
what is trypsinogen activated by?
enterokinase cleaves trypsinogen into trypsin
what is chymotrypsinogen activated by?
trypsin cleaves chymotrypsinogen into chymotrypsin
What is elastase activate by?
what do controacinar cells produce?
bicarbonate to create an alkaline soluition that flushes secretions into duodenum
What does Cholecystokinin (CCK) and secretin do?
induce acinar and controacinar cells activity
what cells release cholecystokinin(CCK) and secretin?
CCK by I cells
secretin by S cells
the endocrine pancreas cells
30% alpha cells: secrete glucagon
65% beta cells: secrete insulin
4% delta cells: secrete somatostatin(inhibits GI and pancreatic endo and exocrine secretes
<1% PP cells: secrete pancreatic polypeptide (inhibits pancreatic exocrine secretion, GI motility, and gastric acid secretion
% referes to amount per islet of langerhan
functions of the liver (4)
dual blood supply, receives 30% of cardiac output
what are the major cell types of the liver?
Sinusoidal epithelial cells
polarized epithelial cells (they are sided)
metabolism carbs, proteins, lipids
produces bile from cholesterol
detoxifies endogenous and xenobiotics
liver specific macs
removes pathogens and debris from the blood
Sinusoidal Epithelial cells
large pores between cells (fenestrae)
No basement membrane
allow large proteins to pass through them
how many lobes are in the liver and what is the rough size of lobules?
there are 8
3mm wide and 7 mm long
what are the two major sources of blood for the liver?
the hepatic artery(30%) and the portal vein(70%)
why is the portal vein said to allow first-pass metabolism?
blood comes from the GI and passes through the liver first.
acts as a sensor for blood concentration levels important signals
classic hepatic lobule modle
-hexagonal prism of portal canals
-blood drains from portal vein and hepatic artery to central vein
-endocrine function focus model
Portal lobule modle
bile drains from hepatocytes to the bile ducts
gradient of hepatocyte oxygenation
hepatic functions differ across the 3 zones
periportal zone, oxygen rich and nutrient rich
most active in regulating blood glucose and protein breakdown
intermediate zone, less oxygen and nutrients than zone I
peripheral zone, oxygen poor
large amount of detox enzymes
lowest blood flow
susceptible toxicity death
ways the liver maintains systemic metabolic homestasis
-fatty acid metabolism
-protein metabolism (deaminates AAs, makes urea)
-storage(vitamins, FAs, Iron)
-protein production (clotting factors, albumin, -apoplipoproteins)
liver detox phase I
Drugs/molecules converted to more polar compounds, oxidized
-cytochrome p450 and microsomal oxidases, makes drug inactivated
-makes a metabolite
liver detox phase II
Drugs/molecules/Phase I metabolites conjugated to hydrophilic molecules(solubilizes them)
-transferase dumps them into bile duct to be excreted
also can be dumped into blood to be sent to kidney to be urinated out
the liver produces bile, what is it?
a heterogeneous secretion, containing bile salts, cholesterol, phospholipids, bilirubin, and waste
why is bile important?
alkalizes intestinal contents
detergent to solubilize dietary lipids and fatty acids
eliminates toxic endogenous waste and xenobiotics
it is recycled
what does the gallbladder do?
it stores and secretes bile