Liver Structure & Function

Question 1

In what section of the abdomen is the liver found?

Answer 1

The upper right quadrant

Question 2

Name the 4 lobes of the liver

Answer 2

Major - Right & left

Minor - Caudate & Quadrate

Question 3

Where do structures enter and leave the liver?

Answer 3

A section on the inferior surface called the porta hepatis. Basically a fissure about 5cm long.

Question 4

What structures enter/exit the liver at the porta hepatis?

Answer 4

(o) Blood - Hepatic artery + portal vein
(o) Lymphatics
(o) Left & Right Hepatic Ducts
(o) Nerves - hepatic nerve plexus

Question 5

What covers the liver.

Answer 5

Visceral Peritoneum & connective tissue capsule

Except at the bare area

Question 6

What is the bare area?

Answer 6

A small area on the liver’s diaphragmatic surface surrounded by the coronary ligament

Question 7

What happens to the connective tissue capsule at the porta hepatis?

Answer 7

it forms a branching network of septa passing into the liver to support it.

Vessels, ducts & nerves follow these septa.

These septa divide the liver into hexagonal lobules

Question 8

How does the portal triad relate to the lobules of the liver?

Answer 8

Each hexagonal lobule has a branch of the hepatic portal vein, artery and duct at its corners.

Question 9

Explain the structure of the hexagonal lobules of the liver?

Answer 9

1) Central Vein at the centre
2) Hepatic cords of hepatocytes radiating out from central vein
3) Lumen called bile canaliculus runs between the cords
4) blood channels called hepatic sinusoids also run between cords

Question 10

explain the passeage of bile

Answer 10

Bile salts secreted by hepatocytes

• -> Into bile canaliculi
• -> Into bile ductules
• -> Into Hepatic Ducts
• -> Common hepatic duct
• -> Merge with cystic Duct to become common bile duct
• -> Merge with pancreatic duct to become hepatopancreatic ampulla
• -> Passes through sphincter of Oddi and out the major duodenal papilla into duodenum

Question 11

where do the hepatic sinusoids drain from/to? and whats their purpose?

Answer 11

they drain blood from the hepatic portal vein & artery, through the sinusoids and into the central vein.

They allow all the hepatocytes to be in contact with the blood and do their stuff

Question 12

Where do the central veins run to?

Answer 12

The hepatic veins

Question 13

What is the function of hepatocytes?

Answer 13

• Bile Synthesis
• Nutrient Storage
• Nutrient Interconversion
• Detoxification
• Storage of glycogen, fat, vitamins and mineral (e.g. copper & iron)

Question 14

What are the components of bile and their sources?

Answer 14

Synthesized in Liver:

• Bile Acids
• Lecithin
• Cholesterol

Parts of broken haemoglobin:
- Bile Pigments (bilirubin)

Taken from blood during detoxification in liver:
- Toxic Metals

Produced in ductal cells:
- Bicarbonate

Question 15

Whats the purpose of bile?

Answer 15

• Solubilises fat
• Disposes of toxins
• Neutralises Acid

Question 16

What are the various bile pigments and where do they come from?

Answer 16

(o) Bilirubin - Yellow
- Comes from breakdown components of old/damaged erythrocytes
- extracted from the blood by hepatocytes & secreted into bile

(o) Bilirubin modified by bacteria - Brown
- Modification occurs in the large intestine
- Causes faeces to be brown

(o) Reabsorbed Bilirubin excreted in urine- Yellow
- Yellow Urine

Question 17

What is the Gall bladder?

Answer 17

A saclike structure about 8/4cm against inferior surface of liver

Question 18

Describe the walls of the gallbladder?

Answer 18

Mucosa - Folded into rugae like stomach
Muscularis - Smooth Muscle contracts to push out bile
Serosa (connective Tissue)

Question 19

What drains bile from the gallbladder?

Answer 19

Cystic Duct -> Common bile duct -> Hepatopancreatic Ampulla -> Major Duodenal Papilla -> Duodenum

Question 20

What controls bile release into the dudenum?

Answer 20

The sphincter of Oddi, when it contracts it forces bile into the gallbladder.
When it relaxes it allows bile and pancreatic juice into the duodenum

Question 21

What controls the sphincter of Oddi?

Answer 21

Cholecystokinin

Question 22

Explain the pathway of CCK:

Answer 22

Fats & Amino Acids in duodenum

• > CCK released from duodenal cells
• >
  • Decreased Gastric Emptying
• Increased pancreatic enzyme secretion
• Gall bladder contraction
• Sphincter of Oddi relaxation

Question 23

What is bile made from and how much is made a day

Answer 23

Synthesized from cholesterol at a rate of about 0.5g/day

Question 24

How are bile acids made soluble?

Answer 24

Prior to secretion they are conjugated with glycine or taurine to make bile salts

Question 25

How does the gall bladder concentrate bile?

Answer 25

IT draws out the Na and H2O