Liver structure and function

Question 1

What surface areas of the abdomen is the liver in?

Answer 1

Right hypochondriac & epigastric region

Question 2

What is the anatomical relationship between the liver and the diaphragm?

Answer 2

Liver is tucked against the inferior surface of the diaphragm

Question 3

The liver is made up of lobes

What are these called?

Answer 3

2 major lobes –> Left & right

2 minor lobes –> Caudate & quadrate

Question 4

Which major lobe of the liver is bigger?

Answer 4

Right

Question 5

What is the Porta of the liver?

Answer 5

Site of entry/exit of Blood vessels, lymph vessels, ducts and nerves

Located on the inferior surface of the liver

(btec version of the hilum of a lung)

Question 6

What blood vessels enter the porta of the liver?

Answer 6

Hepatic portal vein

Hepatic artery

Question 7

What ducts leave the porta of the liver?

Answer 7

right/left hepatic ducts

these fuse to form the common hepatic duct

Question 8

What nerve(s) would you expect to see in the porta of the liver?

Answer 8

The hepatic nerve plexus

Question 9

What is the fate of the ducts that leave the porta of the liver?

Answer 9

right/left hepatic ducts join and form the common hepatic duct

common hepatic duct is joined by the cystic duct (from gallbladder) to form the common Bile duct

Question 10

When looking at the liver from the front, what separates the right and left major lobes?

Answer 10

The Falciform ligament

Question 11

What small organ would you find to the immediate left of the quadrate lobe?

Answer 11

Gallbladder

Question 12

How are the 2 minor lobes of the liver related anatomically?

Answer 12

The caudate lobe is superior to the quadrate lobe

They are located above and below the porta respectively

Question 13

What covers the liver?

Answer 13

Liver covered by connective tissue capsule and visceral peritoneum

Except for bare area on the right lobe (small area on diaphragmatic surface surrounded by coronary ligament)

Question 14

At the porta of the liver, some freaky shit happens with the connective tissue capsule

What is it and why does it do this?

Answer 14

CT capsule branches into a network of septa within the body of the liver

(imagine the roots of a tree going into the ground)

It does this for structural support

Question 15

The septa within the liver are ‘followed about’ by 3 things.

What are they?

Answer 15

Vessels, ducts and nerves

These follow about the septa

Question 16

The network of septa in the liver end up dividing it into ‘Hexagonal lobules’

What is found in these?

Answer 16

Portal triad at each corner of the lobule:

• hepatic portal vein
• hepatic artery
• hepatic duct

Also nerves and lymph vessels

Question 17

What is the fate of the veins that originate in hexagonal lobules in the liver?

Answer 17

Central veins at each lobule –> Hepatic veins

The hepatic veins eventually feed into the IVC

Question 18

What are hepatic cords?

Answer 18

Small chains of Hepatocytes (functional cells of the liver) located in hexagonal lobules

They radiate out from the central vein of the lobule, to the edge (like spokes on a bike wheel)

Question 19

What are the spaces between hepatic cords called?

Answer 19

Hepatic sinusoids (blood vessels supplying hepatocytes)

Question 20

What is the ‘Bile canaliculus’?

Answer 20

Cleft-like lumen that lies between cells within each hepatic cord

pre-cursors to the ducts

Note they are different from sinusoids - ie they are not outside of the hepatocyte bits (look up diagram)

Question 21

What is the liver’s role in digestion?

Answer 21

production & secretion of bile

Question 22

What are the 6 components of bile?

Answer 22

Bile acids 
Lecithin 
Cholesterol 
Bile pigments 
Toxic metals 
Bicarbonate (HCO3-)

Question 23

Do hepatocytes secrete all the components of bile?

Answer 23

Nah

Bile acids, Lecithin, Cholesterol, Bile pigments and toxic metals are all secreted by hepatocytes

Bicarbonate is produced by Duct cells

Question 24

What is the key ingredient in bile pigment?

Answer 24

Bilirubin (from haemoglobin)

from old/damaged erythrocytes

Question 25

Describe the production/secretion process for bile acids

Answer 25

Synthesised in liver from cholesterol (0.5g/day)

Before secretion, bile acids conjugated with glycine or taurine to make Bile Salts (more soluble)

Secreted bile salts recycled via enterohepatic circulation

Question 26

Where is the gallbladder located in relation to the liver?

Answer 26

Located on the inferior surface of the liver

Question 27

What are the 3 layers of the wall of the gallbladder?

Answer 27

mucosa (folded rugae expansion)

muscularis (smooth muscle) contraction

serosa (connective tissue)

Question 28

What duct comes from the gallbladder?

Answer 28

Cystic duct

Question 29

What is the sphincter of Oddi?

Answer 29

the smooth muscle that surrounds the end portion of the common bile duct and pancreatic duct

Used to control the flow of bile, enzymes etc into the duodenum

Question 30

What happens to bile inside the gallbladder and how?

Answer 30

Gets mad concentrated (5-20x) due to extraction of Na+ and H2O from the bile

Question 31

What causes relaxation of the Sphincter of Oddi?

Answer 31

Fat/amino acids in duodenum causes CCK release

CCK causes relaxation (as well as other things)