Lecture 11: Histology of the Accessory Organs of the GI tract Flashcards
What are the 3 main digestive glands?
The major salivary glands.
The exocrine pancreas.
The liver (and gallbladder).
What are the 5 steps of the pathway of saliva flow from acinus to lumen?
(Name the ducts in order.)
Acinus (sacs)
Intercalated duct.
Striated duct.
Excretory duct.
Lumen.
Hallmarks of:
mucous acini
serous acini
mucoserous acini
- ) cloudier cytoplasm secrete thick glycoprotein product
- ) clear cytoplasm, secrete water based product
- ) core of mucous cells surrounded serous demilune
Hallmarks of the…
Parotid gland:
Sublingual gland:
Submandibular gland:
serous, has adipose cells, CN VII passes through
has no capsule, CT divides it into lobes
capped by serous demilunes, shorter intercalated and longer striated ducts compared to parotid
What sort of secretions come from the parotid gland?
Sublingual gland?
Submandibular gland?
Serous
Mixed, mostly mucous
mixed, mostly serous
What are the major cells of the exocrine pancreas?
Pancreatic acinar cells make up the acinus
Centroacinar cels transition between acinus and Intercalated duct
duct cells line the ducts, covered in cuboidal epithelium
Describe pancreatic acinar cells
well developed RER and golgi, have granules that secrete zymogens (proteases, lipases and amylases)
What cells make up the endocrine pancreas?
a cells (glucagon), B cells (insulin), d cells (somatostatin), PP cells (pancreatic polypeptide)
They make up islets of langherhands (spherical masses surrounded with reticular capsule)
Describe the structure of the liver
covered in mesothelium capsule, hepatocytes arranged in cellular “cords” radiatng around a central vein
describe the structure of hepatocytes
large polygonal, eosinophilic cells, large sER, Golgi and peroxisomes
drain bile into the bile canaliculus which merge to form the biliary tree
What is a hepatic lobule?
hepatocyte cords radiating around a central vein forms a lobule (form a hexagon)
each hepatocyte separated from each other by sinusoids
Each end of the hexagon has a protal triad (a, v and bile canaliculus)
What are Kupffer cells?
What are stellate cells?
- macrophages that lie between the hepatocytes and sinusoids, phagocytose old erythrocytes
- stores lipids (vitamins)
What is the perisinusoidal space (of Disse)?
also lie between sinusoids and hepatocytes
space of exchange between blood in the sinusoids and hepatocytes
What is the bile canaliculi and how does bile leave the liver?
collect the bile made by the hepatocytes > drain into the canals of Hering and to the cholangiocytes that line the bile duct
What is a portal lobule?
space between 3 portal veins (imaginary lines forrming a triangle)
basically all the bile made within this triangle drain to the same bile duct
What is the liver acinus and what is the significance?
a functional unit of the liver, characterized by diamond shaped space between two lobules
shows distribution of blood flow to the hepatocytes (zone 1 gets the most blood, zone 3 gets the least, but if there’s toxic stuff in the blood this means zone 1 will get the most damage)
Describe the features of the gallbladder
highly folded mucosa over the lamina propia, muscularis muscle surrounding the organ
Which part of the gallbladder is covered with adventitia, and which part is covered with serosa?
The gallbladder is covered with adventitia where it lies against the liver.
The part of the gallbladder that is exposed is covered with serosa.
What are Rokitansky-Aschoff sinuses?
deep diverticular of mucosaa that extend through the muscularis externa of the gallbladder
result of hyperplasia or epithelial cell herniation through the muscularis externa, can get inflamed and increase risk for gallstones
