Lecture 13: Accesory organs Flashcards
What are the digestive enzymes secreted in the pancreas?
trypsin, lipase, RNAase, elastase
Characteristic exocrine cells of the pancrease:
acinar cells
Characteristic endocrine cells of the pancreas
cells of islet of langerhans
Intercalated ducts in the pancreas secrete:
water and bicarbonate - stimulated by secretin
What are the terminal cells of intercalated ducts?
centroacinar cells
what are the specialized interlobular ducts of the pancreas called and what kind of epithelium do they exhibit?
intercalated ducts - columnar epithelium
What two ducts join at the ampulla of vater?
common bile duct and main pancreatic duct
What is the sphincter of oddi
the major duodenal papilla - controls secretion to duodenum
What is the duct of santorini
the minor duodenal papilla - controls secretion of accessory pancreatic duct
amylase digests
carbohydrates
trypsin digests
protein and peptides
deoxyribonuclease digests
DNA
ribonuclease digests
RNA
lipase digests
Lipids
cholesterol esterase digests
cholesterol
trypsin inhibitor is produced by what cells?
acinar cells
What four mechanisms are used to prevent autodigestion of the pancreas?
- digestive enzymes are packaged in vesicles
- digestive enzymes are inactivated by low pH in vesicles (H+ pump)
- Digestive enzymes begin are proenzymes
- inhibitory molecules keep enzymes inactive
hepatocytes mainly secrete what?
bile
What is the CT sheath that covers the liver called?
Glisson’s capsule
What is the percentage break down of the blood supply of the liver?
Receives 35% of its blood from the systemic circulation, but the other 65 % of its blood from hepatic portal system
What is the relation of blood flow direction and bile flow?
they are opposite
What is the portal triad?
hepatic artery, hepatic vein, bile duct
Where is the portal triad located?
the portal space of kiernan
Where can you find the space of disse
between the sinusoids and hepatocye
where are kupffer cells found and what is their function?
in the space of disse, they destroy bacteria that enters the liver via portal circulation
What three cells are found in the space of disse?
Kupffer cells, Pit (natural killer) cells, hepatic stellate (ito) cells
What is the function of a pit cell?
it is activated by interleukins to kill tumor cells
What is the function of a hepatic stellate cell?
it stores vitamin A, it can transform into collagen secreting cells when injured –> cirrhosis of liver (excessive collagen)
What are the three ways to view the liver
- Classic hepatic lobule
- portal lobule
- portal acinus
Describe the classic hepatic lobule
drains blood from portal veins and hepatic ateries to hepatic/central v.
has central vein in middle
Describe portal lobule
drains bile from hepatocytes to bile duct duct
triangular, with bile duct in the middle
Describe portal acinus
supplies oxygenated blood to hepatocytes has three zones, zone I is the most oxygenated, it is the first exposed to the blood
What is the function of the gall bladder?
it stores and concentrates bile
What controls SM contraction in gall bladder?
CCK and ACh
Describe the two different types of cholelithiasis
- Cholesterol - yellow soft, 70-100% cholesterol
2. Pigmented- hard stones, brown or black,
Describe jaundice and the causes (3):
Increased levels of bilirubin- yellowing of skin, sclera, and mucous membranes
- liver cant remove excessive bilirubin
- defect in liver prevents unconjugated bilirubin from converting into conjugated bilirubin
- blockage of bile ducts impedes flow of bile to SI to digest bilirubin (cancer pancreas head)