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