Accessory Digestive Organs Flashcards
What are the major functions of the liver?
- detoxification of metabloic waste
- detoxification of drugs and toxins
- destruction of senescent RBC
- recycling of Hb via synthesis of bile
- synthesis of plasma proteins
- miscellaneous metabolic functions
Oxygenated blood supplied to liver by __________
hepatic artery (branch of celiac)
Products of digestion enter liver via _____________
hepatic portal vein (75-80% of blood to liver)
The liver is a nutrient rich but ____ poor environment?
O2
The hepatic artery carries only _______ percent of blood to the liver.
20-25%
What is the pattern of venous drainage of lobules via…
central vein -> hepatic vein -> IVC
What are the four types of cells in the liver?
- hepatocytes
- endothelial cells
- kupffer cells
- stellate cells
What is the function of the hepatocytes of the liver?
- main functional cell
- arranged in plates or cores around sinusoids
Where are the endothelial cells of the liver located?
line the sinusoids
What is the function of the kupffer cells in the liver?
liver-specific macrophages
What is the function of the stellate cells in the liver?
storage of vitamin A
What type of ploid are hepatocytes?
most are diploid but some are polyploid and binucleate
What do hepatocytes contain?
- large # of cytoplasmic granules
- rER and lysosomal products
- storage products
What do aging hepatocytes accumulate?
brown pigment; lipofuscin
What is the hepatic architecture of the hepatocyte?
- polyhedral
- round nucleus
- displaced chromatin
- prominent nucleolus
What are individual hepatocytes arranged in?
anastomosing cords (paralleled by venous sinusoids)
What are the sinusoids in the liver lined by?
sinusoidal lining cells
Hepatic cords and sinusoids are supported by what?
meshwork of reticulin fibers (type 3 collagen)
What type of cells are within sinusoids and space of Disse and are phagocytic?
kupffer cells
What cells are occasionally located between hepatocytes?
stellate or ito cells
What is the function of stellate/ito cells?
fat-storing cells containing lipid droplets, used for vitamin A and D storage
What cells have cytoplasm that becomes packed with black carbon particles?
kupffer cells
What are the characteristics of kupffer cells?
- oval nuclei
- closley associated with sinusoidal spaces
What are the functions of the kuppfer cells?
- remove foreign particles
- destroy old RBC (with the spleen)
If the liver is injured what cell becomes a transition cell and is capable of synthesising collagen type I, III, IV, and laminin?
stellate
What are hepatic sinusoids?
- thin, discontinous, highly fenestrated endothelium that does not rest on a basement membrane
What separates the hepatic sinusoids from the hepatocytes?
space of Disse or perisinusoidal space
What does the space of Disse contain?
- blood plasma
- microvilli of hepatocytes
What do the low resistant vascular channels in the hepatic sinusoids allow for?
allows blood to come into contact with hepatocytes over a large surface area
Where is bile made and secreted?
- made by hepatocytes
- secreted into bile canaliculi between cells
What is a classic lobule?
- based on blood flow
- roughly hexagonal
- central vein in the middle
What is around the classic lobule?
thin, connective tissue septum
What is a portal tract?
- located at each corner
- contains hepatic artery, portal vein, lymph, and bile duct
Blood enters from portal tracts and travels through sinusoids of lobule and then drains via ________?
central vein
What is a portal lobule?
- triangular area
- based on bile flow
What is the diamond-shaped region between two central veins?
acinus
How are the central veins and portal tracts related in liver acini?
central veins located along longitudinal axis with portal tracts at sides
What zone of the hepatic acini is closest to portal tract and recieves the most oxygenated blood?
zone 1
What zone of the hepatic acini is the intermediate zone?
zone 2
What zone of the hepatic acini is most susceptible to toxic injury?
zone 1
What zone of the hepatic acini is furthest from the portal tract and receives the least oxygenated blood?
zone 3
What zone of the hepatic acini is the most susceptible to ischemic injury?
zone 3
How does the liver function in detoxification of various drugs, toxins, and metabolites?
microsomal mixed function oxidase system of sER or peroxidases of peroxisomes (P450 system)
What are the characteristics of cirrhosis?
-hepatic degeneration and necrosis
- fibrosis and nodular regeneration
- portal hypertension
- due to repeated insults or chornic disease
What is the muscular sac located in depression along surface of lvier?
gallbladder
What is the gallbladder lined by?
simple columnar epithelium with apical microvilli
What layer does the gallbladder lack?
muscularis mucosae
What stimulates contraction of gallbladder?
CCK (cholecystokinin)
What is the volume that the gallbladder can hold?
100 mL
What is the best known bile pigment that is non-soluble?
bilirubin
What is jaundice?
accumulation of bile pigments (failure to absorb bilirubin or failure to conjugate it)
What leads to gallstones?
supersaturation of bile
What can obstruction of bile ducts (choledocolithiasis) cause?
bile stasis
jaundice (icterus)
What is cholecystitis?
chronic inflmmation of gallbladder
What are the components of bile?
water, ions, electrolytes, cholesterol+ phospholipids, bile acids, and bile pigments
Where is the ductless endocrine pancreatic tissue located?
islets of Langerhans
What type of gland is the exocrine in the pancreas?
compound, acinar, serous gland
What do acinar cells contain?
zymogen granules
What are some exocrine products from the pancreas?
trypsinogen
chymotrypsinogen
amylase
lipase
Where do exocrine products of the pancreas empty into?
intercalated ducts
What are the beginning of intercalated ducts in the center of acini called?
centro-acinar cells
Where do interacalated ducts empty?
larger intralobular ducts
Where do intralobular ducts empty?
larger interlobular(extralobular) ducts
Where do pancreatic secretions enter the duodenum?
pancreatic duct at the major duodenal papilla
What are the pancreatic regulation of polypeptide hormones?
1 secreted by stomach (gastrin)
3 secreted by duodenum (secretin, CCK, enterokinase)
What hormone stimulates secretion of pancreatic fluid?
gastrin (G cells of pyloric stomach)
What hormone stimulates secretion of bicarb by cells of intercalated discs?
secretin (S cells)
What hormone stimulates acinar cells to secrete zymogens?
CCK
What hormone converts trypsinogen to trypsin which in turn converts chymotrypsinogen to chymotripsin?
enterokinase
What is the autodigestion of pancreas brought on by alcoholism?
pancreatitis (can be fatal within hours)
What causes pancreatitis?
premature conversion of chymotrypsinogen to chymotrypsin and autolysis
Someone help me with the two blood flow in the liver slides?
I don’t know how to make them notecards and I kinda don’t get it
