Liver & Pancreas Histology Flashcards
What are the primary tissue types in the liver?
hepatocytes, blood vessels and lymphatics, connective tissue, capsule, serous external surface
What are the features of hepatocytes?
lots of rough ER, lots of smooth ER, lots of mitochondria, often more than one nucleus
What is the lifespan of a hepatocyte?
150 days
What may happen after extensive liver repair?
Liver may not regrow the same lobular structure
What is a lobule?
A structural unit of the liver
What are the two blood supplies of the liver?
arterial supply and hepatic portal system
What is the portal triad?
hepatic artery, portal vein and bile duct
How can you distinguish the bile duct from the artery and the vein?
The bile duct has columnar epithelium instead of squamous epithelium
What is the central vein?
A vein where the sinusoids drain into that carries blood to the hepatic vein and then into the IVC
What are liver sinusoids?
Specialised capillaries in the liver that carry both oxygenated and deoxygenated blood together
What are the features of sinusoids?
larger than other capillaries, wavy lining to increase surface area, lining is discontinuous, gap between endothelium and hepatocyte (space of Disse), macrophages on inner walls (Kupfer cells)
What is the classic lobule model?
Defines the lobule based on the central vein being in he middle and the portal triad around the outside (hexagon)
What is the portal lobule model?
Defines the lobule based on the centre being the portal triad and surrounded by central veins (triangle)
What is the acinar lobule model?
Defines the lobule based around two central veins with the midpoint receiving the most oxygen (oval) – diagram in Evernote
What is the exocrine function of the liver?
producing bile
What are canaliculi?
channels between hepatocytes to collect bile
In what direction does bile flow?
outwards
What is the histological structure of the gall bladder?
simple columnar epithelium - with nothing else
What is the histological structure of the exocrine pancreas?
Each cell has a basal part with high density of rough ER so it stains blue and a lumenal part containing inactive digestive enzymes so it stains pink
What are pancreatic acini?
pancreatic glands in a ball with a central duct
What are the islets of Langerhans?
clusters of hormone secreting cells in the pancreas
How much of total pancreas volume is endocrine pancreas?
1-2%
What is the function of the endocrine pancreas?
Release insulin and glucagon
What does the pancreas overall look like on a H&E stain?
most areas are dark - these are the exocrine areas with a few pale patches which are the islets of Langehans (endocrine areas)
