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T/F The pancreas is both an exocrine & endocrine organ.



What do pancreatic acinar cells do?

It produces, stores, & releases digestive enzymes. It also produces trypsin inhibitor that protects the pancreas. It is super full of zymogen granules.


What influences the release of enzymes from pancreatic acinar cells?

It is influenced by hormones & parasympathetic innervation...


What is the purpose of releasing bicarb? What produces the bicarb?

It buffers the acidity of the chyme as it enters the small intestine. This helps create the optimal pH for the pancreatic enzymes.
Centroacinar cells in the middle of the acinus produce this.


What are centroacinar cells?

modified intercalated duct cells...


How are acinar cells connected to each other?

thru intercalated ducts


T/F Striated ducts & myoepithelial cells are present in the exocrine pancreas.

False. They are NOT.


Which part of the pancreas is endocrine?

islets of Langerhans


Which cells are found in the islets? What does each secrete?

alpha cells--glucagon
beta cells--insulin
delta cells--somatostatin


What do PP cells secrete in the islets? D cells? EC cells?

PP cells: pancreatic polypeptide
D cells: vasoactive intestinal polypeptide
EC cells: secretin, motilin


Explain the process by which we get zymogen granules.

Inactive proenzymes synthesized in the RER of pancreatic acinar cells.
These are transferred to the Golgi apparatus.
They are concentrated in vesicles to form zymogen granules.


What are the 2 things that control the secretion of zymogens?

Enteroendocrine cells in the duodenum secrete peptides that control it.
Endocrine pancreas (islets) synthesize peptide hormones.


What connects acinar cells in the pancreas?

tight jcns-->don't want that crazy stuff leaking out.


What's the dual blood supply of the pancreas?

Acinar Vascular System-->acini
insuloacinar portal system-->islets


What is the function of a portal system?

It slows things down & allows you to pick stuff up & dump stuff...
Like the insuloacinar portal system in the islets...


Describe the deal with the insuloacinar portal system.

Afferent arterioles surround the islet and form capillaries of fenestrated endothelium...the capillaries then supply blood to the surrounding pancreatic acini so that they can get a local reaction to the endocrine hormones secreted by the islets...


T/F The liver, like the pancreas, is both an endocrine & exocrine organ.



What is the main fcn of the liver?

to detoxify toxins & drugs...


What is the liver made up of?

Very little CT & a lot of plates of hepatocytes


Describe the dual blood supply of the liver.

25% of the blood flowin' in is from hepatic arteries
75% of the blood flowin' in is from the portal vein


What drains the blood from the liver?

hepatic veins


T/F Bile flows in the same direction as blood flows.

Countercurrent flow


Describe the arrangement of the hepatocytes.

They arrange in classic lobules that are shaped as hexagons.
3 of them together have a portal area.
Each of the lobules has a central vein that drains blood from the sinusoids of that region.


What is found in the portal area? Where is the portal area?

Portal area found b/w 3 classic lobules
4 things are found there (misnomer of triad)
Hepatic Artery
Portal Vein
Interlobular Bile Duct
Lymphatic Vessels


Where does the central vein from each classic lobule flow to?

Sublobular vein
Hepatic vein
IVC (thru bare area)


What is the purpose of the bare area of the liver?

It allows the vessels from the liver to pass behind the peritoneum and get to the IVC. Thus, it is important to have a spot on the liver where there isn't any peritoneum.


What are the 3 basic concepts of lobules?

Classic Liver Lobule
Portal Lobule
Liver Acinus


What is another name for the Liver acinus?

Acinus of Rappaport


The idea of the classic liver lobule is based on the ___ liver. Describe this lobule concept.

Pig liver.
This is the normal looking lobule with the hexagon shape.
Blood flows from the periphery of the lobule @ portal triad to the central vein (center of lobule)
Bile goes into bile canaliculi & flows from the center to the outside.


The portal lobule emphasize the ____ function of the liver. Describe this lobule concept.

Exocrine function...bile flow in the middle
The portal triad is at the center.
The whole lobule looks like a triangle w/ central veins as its 3 points.