16 - GI: Liver & Pancreas Flashcards
skip 36-40 time GI lecture 16
Liver and pancreas general and relational anatomy
quiz with GN
- diaphragm
- falciform ligament
- round ligament (teres)
- liver: right and left lobes
- gallbladder: neck, body, fundus
- pancreas: head, body, tail
- hepatopancreatic ampulla
- duodenum
Liver external anatomy
more specific
Lobes:
- left
- right (largest)
- caudate
- quadrate
Porta hepatis:
- hepatic arteries (in, oxy blood)
- hepatic veins (out, processed, deoxy blood)
- hepatic portal vein (in, nutrient-rich deoxy blood)
- hepatic ducts (out, bile)
Ducts of the liver
draw quiz
- left and right hepatic ducts
- commmon hepatic duct
- cystic duct (from gallbladder)
- common bile duct
- pancreatic duct (from pancreas)
- hepatopancreatic ampulla
Blood supply to the liver
quiz with GN
!!simplified diagram
Cells of the liver
GN
hepatocytes (predominant): synthesis, storage, detoxification, metabolism
kupffer cell: macrophages within blood vessels- hepatic sinusoids
- kill pathogens, promote proinflammatory cytokines
- make up 80% of body’s macrophages
- very leaky membrane in sinusoids
Portal/Hepatic triad
GN
portal venule: blood from hepatic portal v. to hepatic v.
portal arteriole: blood from hepatic a. to liver cells
bile duct: bile from bile canaliculi to hepatic ducts
Roles of the liver
basic list
- process/store nutrients
- synthesis of serum proteins
- process drugs and hormones
- storage of iron and excretion of bilirubin
- aid in digestion (bile)
Carbohydrate processing
- store glucose as glycogen
- can convert glucose into fatty acids or triglycerides
- convert galactose and fructose to glucose
- create glucose
- glycogenolysis: glycogen to glucose
- other (lactic acid, pyruvate…) to glucose
Amino acids processing
- allows essential AA’s to be used for protein processing
- converts toxic ammonia to urea, to be excreted by kidneys
Lipid processing
packages fats for transport using lipoproteins
- VLDL fats to adipocytes
- LDL cholesterol to tissues
- HDL return excess cholesterol to liver, secreted in bile
Fat soluble vitamin processing
vitamins transported via lacteals to liver
A: vision
D: bone metabolism
E: antioxidant (free radical scavenger)
K: form functional coagulation factors (eg: prothrombin)
Serum protein synthesis
liver synthesizes most plasma proteins
- albumin: transports through blood (hormones, cations, bilirubin…)
- coagulation factors
- complement proteins
- alpha (eg: angiotensin) and beta globulins (eg: transferrin)
Drug and hormone processing
- most drugs pass through liver
- can alter/excrete (remove) excess thyroid and steroid hormones
Iron storage & bilirubin excretion
- stores iron using ferritin (~10% of all iron in body)
- iron binds to transferrin for transport
- heme from RBC’s discarded as bilirubin
role of liver in fat digestion
- bile salts from bile emulsify fats
Gallbladder
location, structure, basic function
cholesterol in bile can precipitate to form gallstones- can get lodged in ducts
can be removed, will lead to insufficient bile storage- poor digestion of fatty meals
gallbladder function control
PNS: weak contractions of gallbladder
CCK: intense contractions
Secretin: increases bile production in liver
gallstones can lead to what pathology involving the pancreas and why?
pancreatitis (inflammation of pancreas)
- increased pressure caused by gallstone blockage injures pancreas
- inflammation can lead to autodigestion
Pancreatic exocrine function
mechanism, regulation
exocrine products: pancreatic enzymes + juices
(bicarb-rich mucous, amylase, lipase…)
controlled by:
secretin: more bicarb-rich mucous
CCK: secretion and production of enzymes
Pancreatic endocrine function
mechanism, regulation
insulin: produced in beta cells (decrease BG)
glucagon: produced in alpha cells (increase BG)
