Liver Structure and Function

Question 1

What is the anatomy of the liver?

Answer 1

2 major lobes - right and left

2 minor lobes - caudate and quadrate

Question 2

What is the porta?

Answer 2

The region on the inferior surface of liver where the hepatic artery, portal vein and duct enters/exits

Question 3

How many hepatic ducts are there?

Answer 3

Right and left that both feed into the common hepatic duct

Question 4

What nerve supply does the liver have?

Answer 4

Hepatic nerve plexus

Question 5

Where does the common hepatic duct go?

Answer 5

Common hepatic duct joined by cystic duct from the gallbladder

Then feeds into common bile duct + pancreatic duct which goes into the sphincter of oddi to the duodenum

Question 6

What is the liver covered by?

Answer 6

A CT capsule
Visceral peritoneum (except for bare area)

Question 7

What is the bare area?

Answer 7

Small area on the diaphragmatic surface which is surrounded by coronary ligament

Question 8

What is the structure like at the porta?

Answer 8

A CT capsule

A branching network called septa which goes into body of liver to support it

Question 9

What does the septa do to the liver?

Answer 9

Divides it into hexagonal lobules

Question 10

What is the portal triad?

Answer 10

hepatic artery, vein and duct - these 3 are located at each corner of the hexagonal lobules

Some nerves and lymphatics also there

Question 11

What is in the middle of the hexagonal lobules?

Answer 11

Central veins that drain into the hepatic veins

Question 12

What radiates out from the central veins like spokes on a wheel?

Answer 12

Hepatic cords - made from hepatocytes, the functional cells of the liver

Question 13

What is the bile canaliculus ?

Answer 13

A cleft like lumen that lies between the cells of each hepatic cord

Question 14

What are the spaces between the hepatic cords called?

Answer 14

Hepatic sinusoids

Question 15

What is the alimentary role of the liver?

Answer 15

Production and secretion of bile

Question 16

What is bile made from?

Answer 16

Cholesterol

Question 17

What is the difference between a bile acid and a bile salt?

Answer 17

Before secretion - bile acids are conjugated with glycine or taurine making it a bile salt which increases solubility

Question 18

Where do bile pigments come from?

Answer 18

Bilirubin - extracted from blood by hepatocytes and excreted into bile making yellow bile

Question 19

Why is bilirubin brown in faeces?

Answer 19

Modified by bacterial enzymes turning pigments brown

Question 20

Why is urine yellow?

Answer 20

Reabsorbed bilirubin excreted in urine

Question 21

What is bicarbonate secreted by?

Answer 21

Duct cells

Question 22

Shape and location of gallbladder?

Answer 22

Sac like

Inferior surface of liver

Question 23

Layers of the gallbladder?

Answer 23

Mucosa - folded rugae
Muscularis - smooth muscle
Serosa - CT

Question 24

How does the gallbladder transport bile?

Answer 24

Feeds into cystic duct which feeds into the common bile duct

Question 25

What controls bile secretion?

Answer 25

Presence of fat in duodenum causes release of CCK

CCK causes sphincter of oddi to relex and the gallbladder to contract

Question 26

Summarize what secretin does.

Answer 26

Acid in the duodenum releases secretin which =

• Reduced HCL secretion
• Reduced gastric emptying
• Increased duodenal, bile duct and pancreatic bicarb secretion

Question 27

Summarise what cholecystokinin does.

Answer 27

Fat/acid in duodenum = release of cholecystokinin =

• reduced gastric emptying
• increased pancreatic enzyme secretion
• increased bile secretion
• relaxation of sphincter of oddi