Liver Structure and Function

Question 1

What are the lobes of the liver?

Answer 1

• 2 Major lobes: Right > Left
• 2 Minor lobes: Caudate, Quadrate

Question 2

What blood vessels exit/enter the liver?

Answer 2

hepatic portal vein, hepatic artery

Question 3

What else other than blood vessels exit/enter the liver?

Answer 3

•, lymphatic vessels, ducts (right/left hepatic ducts Þ common hepatic duct), nerves (hepatic nerve plexus) via Porta on inferior surface

Question 4

What is the common bile duct composed of?

Answer 4

Common hepatic duct + cycstic duct of gall bladder

Question 5

What joins onto the common bile duct?

Answer 5

Pancreatic duct - forming the major duodenal papilla (sphincter of oddi)

Question 6

What is the liver covered in?

Answer 6

Connective tissue capsule and visceral peritoneum except for bare area.

The bare area is surrounded by coronary ligament and is found on the diaphragmatic surface

Question 7

Define porta hepatis

Answer 7

The porta hepatis or transverse fissure of the liver is a short but deep fissure, about 5 cm long

Question 8

What structure provides support in the liver?

Answer 8

The connective tissue capsule provides a branching network of septa into the body of the liver

(·Vessels, ducts and nerves follow septa throughout liver)

Question 9

How are hexagonal lobules formed?

Answer 9

Septa divide

Question 10

What is the portal triad?

Answer 10

Hepatic portal vein

Hepatic artery

Hepatic duct

Question 11

Where are portal triads located?

Answer 11

At the corner of each hexagonal lobule

Question 12

How does the blood from a lobule enter the IVC?

Answer 12

Travels to the central vein of the lobule - hepatic vein - IVC

Question 13

Define Hepatic chords, Bile canaliculus and hepatic sinusoids

Answer 13

Hepatic chords are chains of hepatocytes that radiate out from the central vein like spokes on a wheel.

Cannaliculi ie between cells within each chord

Hepatic sinusoids are blood chanels that fill the space between hepatic chords

Question 14

What do the bile cannaliculi eventually form?

Answer 14

The bile duct

Question 15

What feeds into hepatic sinusoids?

Answer 15

The hepatic portal vein, the hepatic artery and some of the products of hepatocytes (basically everything that needs to go to the central vein)

Question 16

What is the direction of transport of materials from the hepatic sinusoids?

Answer 16

Some travel to the central veins

Others travel to the hepatocytes (probably excess nutrients and toxins)

Question 17

What is the transport from the central vein?

Answer 17

Travels to hepatic veins

Question 18

What is contained within the blood coming from the hepatic portal vein?

Answer 18

Question 19

What is contained in the blood coming from the hepatic artery?

Answer 19

O2 - rich nutrient depleted blood

Question 20

What substances are found within the hepatocytes?

Answer 20

Bile

Nutrient storage

Glycogen

Fat

Vitamins (B12,A,D,E,K)

Copper

Iron

Nutrient interconversion

Detoxification

Question 21

What is the movement of bile that has been synthesised by hepatocytes?

Answer 21

Travels to cannaliculi to hepatic ducts

Question 22

What is the alimentary role of the liver?

Answer 22

Production and secretion of bile

Question 23

What are the components of bile?

Answer 23

Question 24

What is responsible for the formation of Bile acid, Lethicin, Cholesterol, Bile pigments, toxic metals?

Answer 24

Secreted by hepatocytes

Question 25

What is responsible for the formation of bicarbonate?

Answer 25

Duct cells

Question 26

What are bile pigments?

Answer 26

Breakdown products of haemoglobin from old/damaged erythrocytes

Question 27

Where does bilirubin come from?

Which is the predominent bile pigment

Answer 27

Extracted from blood by hepatocytes and secreted into bile (forms yellow bile)

Question 28

What causes faeces to become brown?

Answer 28

Bacterial enzymes modify bilirubin to produce brown pigments

Question 29

What causes urine to be yellow?

Answer 29

Billirubin is reabsorbed

Question 30

What are bile acids synthesised from?

Answer 30

Cholesterol (0.5 g/day)

Question 31

How is bile modified before secretion?

Answer 31

Bile acids are conjugated with glycine or taurine

(increases solubility)

Question 32

How are bile salts recycled?

Answer 32

Via enterohepatic circulation (95 % is recycled, 5% is lost in faeces)

Question 33

What happens to the bile produced when the sphincter of Oddi closes?

Answer 33

Prevents bile entering the second part of the duodenum.

Bile now backs up into the gall bladder where it Is stored and concentrated

Question 34

What is the pathway from the liver back to the liver?

Answer 34

Liver - bile duct - duodenum - ileum - hepatic portal vein - liver

Question 35

Where is the gallbladder located?

Answer 35

On the inferior surface of the liver

Question 36

Describe the mucosa in the gallbladder

Answer 36

Folded - rugae - for expansion

Question 37

What is inbetween the gallbladder and the common bile duct?

Answer 37

The cystic duct

Question 38

What happens to the gallbladder when CCK is released in the duodenum?

Answer 38

Sphincter of Oddi relaxes and the gallbladder contracts

Bile now solubilises fat

CCk also promotes pancreatic enzyme secretion (lipase)

Question 39

What type of diet will result in less concentrated bile?

Answer 39

A fatty diet because the gallbladder is always emptying so will never get a chance to concentrate

Question 40

Summary of secretin and cholecystokinin

Answer 40