Histology of the Liver, Gallbladder & Pancreas - Cirilo Flashcards
What are the four functional tissue elements of the liver?
Connective Tissue
Large Vessels (blood, lymph, nerves, bile ducts)
Sinusoidal Capillaries
Hepatocytes
What does the hepatic portal vein do?
What does the central vein carry?
carries venous blood into the liver
carries venous blood away from the liver
Where does portal vein blood come from? Why?
Intestines- organization of nutrients/filtering
Pancreas- circulates glucagon and insulin
Spleen- recirculates heme
What role do the sinusoids play?
they act to distribute blood from the portal veins to the hepatocytes
What makes up the portal triad?
Portal Vein
Hepatic Artery
Bile Duct
Lymphatics
What type of capillaries are the sinusoids?
Type III (large gaps between cells)
What two types of cells make up sinusoids?
Endothelial cells (fenestrated) Macrophages (Kupffer cells)
What is the ‘space of Disse’? Where is it in relation to the sinusoids?
Space for exchange of substances
It surrounds the sinusoids
What is in the space of Disse?
Stellate cells
Hepatocyte microvilli
What do stellate cells do?
Store Vitamin A
Synthesize reticular fibers
What are the three functional units of the liver?
Classic lobule (hexagon of hepatocytes surrounding a central vein)
Portal lobule (3 central veins surrounding the portal area)
Liver acinus (2 central veins, 2 portal areas, forming a diamond)
How is the liver acinus further subdivided?
How are these areas different?
Zone 1,2, and 3
Zone 1 is closest to the artery, stores the most glycogen and receives the most toxins
Zone 3 is farther away from both nutrients and toxins
How are hepatocytes arranged?
“plates” 1-2 cells thick sandwiched by sinusoids
What do hepatocytes look like histologically?
- Large spherical nucleus
- Typically binucleate (tetraploidy)
- Multiple RER and Mitochondria
- Glycogen and lipid droplets
What is the reticular network?
What makes up the reticular network?
What synthesizes the reticular network?
Parenchyma that supports the hepatocytes and sinusoids
collagen III
stellate cells
Where is bile synthesized?
In the hepatocytes
How does the bile collect into gall bladder?
ATPase transfers the bile into the canaliculi
The canaliculi form canals of Herring
What kind of epithelium lines the biliary duct?
cuboidal epithelium
How much bile is secreted everyday?
How much bile does the gallbladder store per day?
1 liter
100mL (The wording in the slide confused me, but I think they are implying that most of the bile in the intestinal tract at any one time)
What is the mucosa of the gallbladder like?
Simple columnar epithelium
short apical microvili
basally located nucleus
What is the macrostructure of the pancreas?
Highly lobular connected by loose collagenous tissue
Arrange the following pancreatic ducts in order of size:
pancreatic, interlobular, intralobular, intercalated
(smallest) intercalated intralobular interlobular pancreatic (largest)
What is the endocrine unit of the pancreas?
Where in the pancreas is it found?
Islet of Langerhans
randomly distributed throughout the exocrine tissue
What is the exocrine unit of the pancreas?
Acini
What pancreatic cells respond to CCK?
What cells respond to secretin?
Acinar cells secrete zymogen granules
Centroacinar cells secrete alkaline fluid
What is seen in acinar cells?
pyramidal shape
basal nucleus
zymogen granules
extensive RER
How are mature zymogen granules different from immature granules?
How can you tell them apart?
mature granules have been modified by the golgi apparatus
on electron microscopy, mature granules are darker
What path do pancreatic enzymes follow to get to the duodenum?
Centroacinar lumen—> intralobular ducts—>interlobular ducts—>main pancreatic duct
