Liver Physiology Bile and Jaundice

Question 1

What are the functions of the liver?

Answer 1

Removal and detoxification and first pass metabolism of orally administered drugs
Storage
Synthesis eg. albumin, bile, transport proteins

Question 2

What is the role of the Portal Vein?

Answer 2

Drains GIT from the lower esophagus to the rectum

Question 3

What does capillary bed 1 do?

Answer 3

Drains contents from small intestine

Question 4

Where is capillary bed two found?

Answer 4

Within the liver

Question 5

What is the structural unit of the liver called?

Answer 5

The hepatic lobule

Question 6

What three ducts make up the triad found on each apices?

Answer 6

hepatic portal vein, hepatic artery and the bile duct

Question 7

How do we know it’s the bile duct in a histology image?

Answer 7

small lumen, presence of epithelium cells line duct systems

Question 8

What are the white spaces in-between pink cells?

Answer 8

Hepatic sinusoids

Question 9

What types of cells are found in the liver?

Answer 9

Hepatocytes
Reticuloendothelial cells - structure
Endothelial cells
Hepatic stellate cells
cholangiocytes - bile secretion and motility

Question 10

What is the function of the hepatic lobule?

Answer 10

Drains blood from portal vein and hepatic artery to hepatic/central vein

Question 11

What is the function of the portal lobule?

Answer 11

Drains bile from hepatocytes to the bile duct

Question 12

What is the function of the Hepatic Acinus?

Answer 12

Supplies oxygenated blood to hepatocytes

Question 13

What Zone is the most oxygenated and what zone is the least oxygenated

Answer 13

Zone 1 = most oxygenated
Zone 3 = least oxygenated

Question 14

What are the functions of zone 1?

Answer 14

Gluconeogenesis
Oxidation of fatty acids

Question 15

What are the functions of zone 3?

Answer 15

Glycolysis
Lipogenesis
P450 enzyme mediated detoxification

Question 16

What causes portal vein oxygenation to decrease?

Answer 16

Increasing GIT activity and O2 demand

Question 17

What does zone 1 create?

Answer 17

Local microenviroments/

Question 18

What happens when we move further away from the shirt axis?

Answer 18

Nutrients start to deplete

Question 19

Where is bile produced and stored?

Answer 19

Produced in the liver
Stored in the gall bladder

Question 20

What are the functions of bile?

Answer 20

Emulsification of lipids
Hormonal action
Elimination of waste products eg. bilirubin

Question 21

What are the main components of bile?

Answer 21

Water, bile acids, HCO3-, Bilirubin

Question 22

What synthesizes bile acids?

Answer 22

Hepatocytes

Question 23

What is the aqueous component contributed by?

Answer 23

Bile duct epithelial cells (cholangeocytes)

Question 24

What stimulates duct cells?

Answer 24

Secretin but does not affect bile salt synthesis

Question 25

What are examples of primary bile acids?

Answer 25

Cholic acid Chenodeoxycholic acid Synthesized by hepatocytes from cholesterol

Question 26

What are examples of secondary bile acids?

Answer 26

Deoxycholic acid Lithocholic acid Generated by de-hydroxylation of bile acids by intestinal bacteria

Question 27

How are conjugated bile acids formed?

Answer 27

Addition of glycine or taurine groups to primary or secondary acids in the liver

Question 28

How is conjugation beneficial?

Answer 28

Helps solubility of acids for emulsifying lipids

Question 29

How are lipids emulsified by bile?

Answer 29

Hydrophobic side of bile acid binds to lipid Hydrophilic side has polar regions - lipid can't reform - allows lipases to come in and aggregate lipid Surface area for digestion increased Fat droplets coated with bile salts are suspended in water

Question 30

What is urso-deoxycholic acid?

Answer 30

Bile acid used to treat liver and neurodegenerative disease Inhibit apoptosis Abundant in bear bile - only produced in small amounts in human colon

Question 31

What bile acid can act as a signaling molecule?

Answer 31

GPBA control peristalsis, energy homeostasis and anti-inflammatory

Question 32

How does bile enter the duodenum?

Answer 32

Via the sphincter of Oddi Common exit with pancreatic secretions - allows for mixing

Question 33

How are bile acids returned to the hepatocytes?

Answer 33

Via sodium dependent organic anion transporter

Question 34

What does conjugation do to bile acids in the entero-hepatic recirculation?

Answer 34

Increases water solubility of bile salts - renders them relatively impermeable to the duodenum Accumulate in the lumen

Question 35

Where are bile acids reabsorbed?

Answer 35

In the terminal ileum

Question 36

What is the function of the gall bladder?

Answer 36

Storage and concentration of bile Contract to release bile when required

Question 37

What are the three phases of for the gall bladder?

Answer 37

Cephalic, gastric and intestinal phase

Question 38

What is the cephalic phase triggered by?

Answer 38

Thought and taste -> GB emptying

Question 39

What is the gastric phase triggered by?

Answer 39

vagus stimulated by gastric distension -> GB emptying

Question 40

What is the intestinal phase stimulated by?

Answer 40

Presence of acid in the duodenum -> secretin & ductal epithelial cells produce bicarb rich secretion Presence of fat in the duodenum -> CCK & stimulation of contraction of GB

Question 41

How are gall stones formed?

Answer 41

Disregulation or an imbalance of cholesterol, phospholipids and bile salts in bile

Question 42

What are the consequences of removing your gall bladder?

Answer 42

Bile won't be as concentrated Bile is more dilute - less effective at absorbing lipids

Question 43

How is bilirubin removed?

Answer 43

Conjugated to glucuronic acid in the liver Enters biliary system in bile Enters small intestine where bacterial proteases turn it into urobilinogen Mostly emoved as faeces or enters portal vein Goes back into the blood and is excreted in urine via kidneys

Question 44

What is bilirubin?

Answer 44

A breakdown product of heme from red blood cells

Question 45

What is jaundice?

Answer 45

Elevated unconjugated bilirubin in the blood

Question 46

How does jaundice occur?

Answer 46

High levels of Heme breakdown or incomplete conjugation