Liver and Gallbladder

Question 1

Major Liver Functions

Answer 1

• filtration and storage of blood
• metabolism of fats/carbs/proteins
• bile formation
• vitamin/iron storage
• coagulation factor formation

Liver buffers circulating blood glucose!

Question 2

Hydroxylation of Vitamin D

Answer 2

occurs in liver and activates!

T4 –> T3

Question 3

Liver Lobule - Circulation

Answer 3

75% portal vein

25% hepatic artery

Question 4

Hepatocyte

Answer 4

epithelial cells that line bile

Question 5

Kupffer Cells

Answer 5

phagocytes (tissue macrophage) located in liver sinusoids

Main cell system for removal of microbes (removes 99% of bacteria from gut that flows to liver through portal system)

Question 6

Carbohydrate Metabolism

Answer 6

• glycogen storage
• gluconeogenesis
• galactose/fructose to glucose
• formation of intermediate metabolites

Question 7

Liver Maintenance of Blood Glucose

Answer 7

glycogenesis: excess glucose converted to glycogen

glycogenolysis: depolymerization of glycogen to increase blood glucose

gluconeogenesis: glucose prodution from AAs and non-hexose sugars

Cori Cycle: increases glucose to make glycogen (liver does this via de novo synth)

Question 8

Protein Metabolism

Answer 8

• deamination of AAs
• removal of ammonia via kidney/liver by making urea (degrade amines, AAs, purine and urea in gut)
• formation of plasma proteins
• synthesis of non-essential AAs

Question 9

Coaggulation Factors

Answer 9

Vitamin K = cofactor in liver to make clotting factors

(liver actually makes the factor)

liver disease or vitamin K deficiencies lead to bleeding abnormalities (liver requires Vitamin K to make prothrombin and factors 7, 9, 10)

Fibrinogen and accelerator globulin!

Question 10

Fat Metabolism

Answer 10

• conversion of carbs/proteins –> fat
• Beta oxidation of fatty acids (FA move into mitochondria and then turn to acetyl CoA)
• synthesis of lipoproteins, cholesterol (to make bile salts) and phospholipids (cell membrane)

Question 11

Cirrhosis

Answer 11

chronic liver disease

normal liver cells are damaged and replaced by scar tissue

* NOT just alcoholics however alcohol intake is most common casuse as it leads to accumulation of fat within hepatocytes

Question 12

Steatohepatitis

Answer 12

Fatty liver! (fat in hepatocytes)

accompanied by inflammation which leads to scarring of liver and cirrhosis.

Question 13

Ascites Formation

Answer 13

“fluid formation”

• descreased albumin –> decreased plasma COP = ascites
• increased resistance –> increased portal pressure –> ascites

Fix? lose fluid by effective intravascular volume and increased renin!

Question 14

Bilirubin Formation

Answer 14

urobiligen = VERY soluble which means it has choices. . . can be reabsorbed, oxidized or excreted

1) Phagocyte (RBC) breaksdown to release bilirubin
2) bilirubin enters hepatocyte via albumin
3) free bilrubin is taken up by hepatocyte and is conjugated and excreted into bile

Question 15

Jaundice

Answer 15

too much unconjugated bilirubin!!! (system becomes backed up and can’t excrete)

Hemolysis - unconjugated bilirubin overproduction

Neonatal Jaundice - defective conjugation

Cirrhosis/Hepatits - defectiv excretion of all bilirubin

Cancer/Gallstones - obstruction of excretion pathway of all bilirubin

Question 16

Bile Salts

Answer 16

Most abundant solute in bile = bile salts

calcium cannot be absorbed because bile salts are amphipathic!

–> cholic acid (phobic) + glycine (philic) =

glycocholic acid (amphipathic bile salt)

Question 17

Gallbladder

Answer 17

CCK + peristalsis = emptying

emptys through cystic duct when food (especially fatty food) enters duodenum

• CCK sense fat in the duodenum - contracts gallbladder and relaxes sphincter of Oddi
• Duodenal peristaltic waves occur! MOST IMPORTANT
• vagus + enteric (minor role)

Question 18

Feces

Answer 18

1. Melena/Black - upper GI bleed
2. Maroon - middle GI bleed/Chrohns
3. Clay - no bile (blocked)
4. Yellow/Greasy - fat malabsorption/Celiacs
5. Bright Red - anal bleed