Liver, Pancreas, and Intestine Flashcards
How does the liver contribute to digestion?
it creates bile salts vital to fat digestion and absorption and eliminates toxins
How does the pancreas contribute to digestion?
it secretes enzymes involved in fat, CHO, and protein digestions and has secretions that neutralize stomach acid
What are the functions of the liver?
metabolism, secretion, storage, and innate immune defense
How does the liver metabolize lipids?
it oxidizes them for energy, and packages lipids/cholesterol for transport to other organs for energy
How does the liver use carbohydrates?
it uses them for a small amount of energy and stores some as glycogen
what does the liver secrete?
bile
What does the liver store?
lipids, vitamins A, D, and E, and glycogen
How does the liver participate in the innate immune defense?
it has kupfer cells that do phagocytosis
What does blood enter the liver through?
the hepatic artery and portal vein
How does blood exit the liver?
lobule central veins to hepatic veins to posterior vena cava
What is the portal triad made up of?
portal venule, hepatic arteriole, and bile ductule
What do the fenestrated capillaries of the liver allow for?
AA to flow into the bile duct and theb albumin to flow back out
What do quiescent cells do?
deposit fibrin
How does the liver utilize amino acids?
it uses them to make proteins such as albumin, fibrinogen, and clotting factors
How does the liver utilize carbohydrates?
it removes a small amount of glucose for its energy needs- insulin independent
How is the ruminant liver different in its uptake of carbohydrates?
it does not take up glucose, it takes up bulk of volatile fatty acids
How are fats brought to the liver?
they are absorbed into lacteals then go to the thoracic duct and then the left jugular and reach the liver by the hepatic artery
What is choleresis?
the secretion of bile
Where is the bile stored in most species?
in the gall bladder
When is bile released?
when high fat chyme reaches the duodenum
What does bile do?
provides bile salts necessary for fat absorption and an excretory pathway for water insoluble materials
What are bile salts made up of?
they are a conjugation of cholesterol acids with taurine or other amino acids
What stimulates bile secretion, gall bladder contraction, and relaxation of sphincter of oddi?
CCK-PKZ
What is phase 1 of the excretory/detoxification pathway in the liver?
oxidation of the compound
What is phase 2 of the excretory/detoxification pathway?
glucuronidation or sulfation to improve water solubility
What causes the brown color in feces?
stercobilin
What causes the yellow color of urine?
uurobilinogen
What is cholesteral excreted into?
bile canaliculus
What can cause the formation of gallstones?
excessive cholesterol secretion can exceed carrying capacity of bile causes cholesterol to precipitate and form gallstones especially if ungonjugated bilirubin combines with the cholesterol
What can cause the formation of bilirubin stones?
bacteria break glucuronide off of the bilirubin
Through what does the bile duct empty into that then empties into the pancreatic duct?
the major duodenal papilla
What do the acini of the exocrine pancreas do?
they make enzymes
What do the ducts of the exocrine pancreas do?
they add base
What do alpha cells in the pancreas make?
glucagon
What do beta cells of the pancreas make?
insulin
What do delta cells of the pancreas make?
somatostatin
What is the function of the exocrin pancreatic secretions?
the alkaline secretions neutralize acidity of chyme leaving the stomach and are a source of digestive enzymes
How does secretin affect the pancreas?
it stimulates the secretion of more alkaline fluid
What is the function of the pancreatic ducts?
they add Na, K, and HCO3 and remove Cl to create an alkaline secretion
The pancreas secreats many inactive forms of enzymes, what activates most of them?
trypsin
What stimulates the release of enteropeptidase from the duodenum?
CCK
What does enteropeptidase do?
it activates trypsin
What enzyme that the pancreas digests is fully active when secreted?
pancreatic amylase
What does pancreatic amylase do?
breaks down starch, some glucose and dextrins
What are the pancreatic fat/lipid digestion enzymes?
pancreatic lipase, pro-colipase, cholesterol esterase, pro-phospholipase A
What does the pancreatic trypsin inhibitor do?
it is to keep any trypsinogen that might spontaneously cleave from digesting the gland
What can cause pancreatitis?
activation of trypsinogen within acinar cells or ducts or activation of pro-phospholipase A within ducts
How can activating trypsinogen within the acinar cells or ducts lead to pancreatitis?
it leads to the digestion of the pancreas, leakage of enzymes, and peritonitis
What can cause extraluminal pancreatic duct obstruction?
neoplasia or scarring, fibrosis secondary to acute pancreatitis
What can cause intraluminal blockage of the pancreatic duct?
blockage of the papilla or bile duct by call stones, scarring, liver flukes and other parasites
What are symptoms of pancreatic insufficiency?
diarrhea and weight loss
What are the cell types found in crypts?
regeneratibe stem cells, secretory crypt cells, paneth cells, goblet cells, enteroendocrine cells, and M-cells
What do most regenerative stem cells in crypts become?
secretory crypt cells
What do secretory crypt cells secrete?
Na and Cl necessary for absorption of surgas/AA
What happens to secretory crypt cells after 3-5 days?
they migrate up into the villus area and become a villus absorptive cells
What are paneth cells?
highly secretory cells that contain lysozymes
Where are paneth cells located?
at the base of the crypt next to regenerative stem cells
What do goblet cells do?
secrete mucous - also move up the villi
What do enteroendocrine cells do?
they stay in crypts, and secrete secretin, CCK-PKZ, enteroglucagon, VIP, GIP, somatomedins, and others (some gastrin)
What do M cells do?
they capture particales, antigens, pathogens and pas sthem to dendritic cells and lymphocytes within lymphoid follicles in the sub-mucosa
What cells are found in the villus region?
villus absorptive cells, goblet cells, M or dome cells
What do villis absorptive cells do?
actively secrete digestive enzymes and absorption
Where are brunner’sglands located?
below the musclularis mucosa within the submucosa
What do the ducts of the brunner’s glands empty into?
crypts of lieberkuhn
What do brinner’s glands secrete?
mucoid and alkaline solution as protection against stomach acid
What is the secretion from Brunner’s glands stimulated by?
secretin
