Flashcards in 9. Histology of the liver, gallbladder, and pancreas Deck (56):
What is the largest glandular tissue in the body?
What are the four lobes of the liver? Which two have the most bulk?
RIght, left, caudate, quadrate
RIght and left
The liver is unique in that it receives mainly venous blood directly from:
**first organ to encounter any injested toxic substances as well as nutrients
The liver is unique in that CT is sparse, and the bulk of the liver is made up of:
Parenchymal cells/ hepatocytes
6 functions of the liver
1. Detox of metabolic waste products
2. Synthesis of plasma lipoproteins
3. Synthesis of clotting factors
4. Synthesis, storage, and secretion of carbs and lipids
5. RBC destruction and recovery of contents
6. Synthesis and secretion of bile
What are the endocrine secretions of the hepatocytes that enter the hepatic blood?
Alpha 1 antitrypsin
What is the main exocrine function of the liver?
Production of bile
What are the four functional groups of liver components?
Sinusoidal capillaries (sinusoids)
What kind of fibers surround the hepatocytes and sinusoids? Layout?
Reticular fibers--type III collagen
Extend outward from the central vein, only CT in the lobule
Supports the parenchyma and keeps the sinusoids open
What do the reticular fibers originate from? How can their disruption be identified?
Stellate/ito cells in the Space of Disse
Staining for reticulin
What are the five main vessel systems in the liver?
Hepatic artery--oxygenated blood to the liver
Hepatic portal vein--venous blood to the liver
Central veins--blood away from the liver toward the hepatic veins, IVC
Bile ducts--bile from the liver
Lymphatic vessels--lymph away from the liver
Arterial capillaries and inlet venules carry blood from the hepatic artery and portal veins into capillaries called
**lymphatic vessels also associated
Sinusoids are made up of two cell types:
Endothelial cells (sinusoidal cells)
Kupffer cells (sinusoidal macrophages)
Role of Kupffer cells?
Derivatives of monocytes, probably involved in the breakdown of senile RBCs
Where does exchange of substances between the blood and hepatocytes take place?
Peri-sinusoidal Space of Disse (between the basal surface of the hepatocyte and the sinusoid
How do hepatocytes increase their SA for absorption?
Extend microvilli from the basal surface
What calls are found in the perisinusoidal space?
Stellate cells contain ___ and are the major site of ____ stoarage
What is the functional unit of the liver?
What are the three ways that the functional unit of the liver can be described?
Classic lobule (hexagon)
Portal lobule (triangle between three central veins)
The classic lobule has __ at the center and __ at each of its 6 corners
What makes up the short axis and long axis of an acinus?
Short: between two adjacent portal triads
Long: between two adjacent central veins
What zone of the acinus encounters afferent blood first?
Haptocytes are arranged in ___ ___ 1-2 cells thick seperated by sinusoids
Hepatocytes are described as having __ surfaces
6--2 facing the perisinusoidal space and 4 facing other hepatocytes and bile canaliculi
Perisinusoidal surfaces of the hepatocyte represent the ___ aspect of the cell
Surfaces facing the bile caniliculi are ____
Transfer of substances between the sinusoids and hepatocytes occurs at the ___ surface
In the adult, the majority of hepatocytes are __nucelate and ___ploid
Tetraploid (4n DNA)
What orgnanelles are hepatocytes particularly rich in?
**glycogen granules are deposited through the cytoplasm and lipid droplets are also prevalent
What are bipotential cells in the biliary epithelium that can differentiate into both biliary epithelium and hepatocytes?
Main role of bile from the liver
Emulsification of fats for absorption by the intestine
Hepatocytes actively secrete bile across their ___ surfaces into the:
Bile caniliculi join together to form small terminal ductules called:
Canals of herring
Bililary epithelial cells form a ____ epithelium which forms a ductule
Human liver secretes ___ of bile a day
Dilute bile form the liver is shunted into the gall bladder where it is concentrated ____x
The presence of LIPID in the duodenum induces the secretion of ____, which has the role to
Stimulates the gall bladder to contract and forces concentrated bile into the duodenum
The gallbladder can store ____ bile a day
What is the mucosa of the gallbladder made up of?
Simple columnar epithelial cells (resemble the absorbitive cells of the intestine
What is the function of the cells lining the gallbladder (have numerous short apical microvilli and basally located nucleus, junctions to produce barrier)
Concentrate bile by actively absorbing water into a capillary-rich network in the lamina
The main pancreatic duct traverses the length of the organ and joins the
Common bile duct, which enters into the duodenum
What does the exocrine pancrease generally secrete?
Cocktail of enzymes required for digestion
The exocrine pancreas consists of acini that are densely packed and secrete into a system of ducts---(4)
What does the endocrine pancreas consist of?
Islets of Langerhans--randomly distributed through the acini
**secretes hormones that control carbohydrate metabolism
What two hormones produced by the duodenum in the presence of food induce the secretion of pancreatic juice from the exocrine pancreas?
Pancreatic juice is a mixture of ___ fluid and enzymes/proenzymes
Digestive enzymes of the pancreas are stored within ___ ___ within the cytoplasm of acinar cells
To prevent autodigestion of the pancreas, the proenzymes of the pancreas are only activated by:
Protrolytic cleavage in the intestine
**Acinar cells also secrete proteolytic inhibitors that block any errant activation of the proenzymes in the pancreas
The functional unit of the exocrine pancreas is the:
Cholecystokinin induces acinar cells to secrete:
Pancreatic enzymes in the form of zymogen granules into the lumen
What cells respond of secretin?
Centroacinar cells: extend from the end of the duct into the acinus as a discontinuous epithelium--low squamous epithelial cells responsible for the secretion of alkaline fluid
What are the two main roles of the alkaline fluid secreted by centracinar cells in response to secretin?
Solubilization of zymogen granules
Neutralization of acidic chyme as it enters the duodenum
Morphology of acinar cells
Pyramidal cells with basal nucelus--lots of rER for protein synthesis
Newly synthesized proenzymes in acinar cells are modified by ___ to form zymogen granules
Zymogen granules are released by exocytosis at the __ surface of the acinar cells