Liver

Question 1

What are the 5 relevant functions of the liver?

Answer 1

1. Metabolism and storage
   - fat
   - carbohydrates
   - amino acids
   - vitamins and minerals
2. Detoxification
   - drugs and alcohol
   - conversion of ammonia to urea
3. Synthesis
   - bile (IL daily)
   - plasma proteins
   - hormones
   - haemopoeisis (RBC production)
4. Excretion
   - bilirubin in bile
   - erythrocyte breakdown
5. Immunity
   - phagocytic activity

Question 2

Describe the surface anatomy and location of the liver

Answer 2

Location:

• RUQ and most of LUQ
• Right hypochondriac region, most of epigastrium, some of Left hypochondriac region
• underneath right hemisphere of diaphragm

Anatomy:

• approx 1.5kg
• irregular hemisphere with 4 lobes (right, left, caudate, quadrate)
• each lobe has 100,000 lobules

Surfaces:

a. diaphragmatic
- smooth, dome shaped, convex
- sits within concave hemisphere of right diaphragm
- covered with peritoneum except at bare area (posterior)

b. visceral
- inferior and posterior
- covered with peritoneum except at gall bladder and porta hepatis

Border:
- inferior border sharp border separating surfaces anteriorly

Question 3

What is the porta hepatis?

Answer 3

• transverse fissure on visceral surface (between caudate and quadrate lobes)

Passage for:

• portal vein
• hepatic artery
• hepatic nerve plexus
• hepatic ducts
• lymphatic vessels

Question 4

What are the 5 structures passing through the porta hepatis?

Answer 4

Portal vein
Hepatic artery
Hepatic nerve plexus
Hepatic ducts
Lymphatic vessels

Question 5

What are the 5 peritoneal ligaments of the liver?

Answer 5

Falciform:

• connects liver to anterior abdominal wall and diaphragm
• divides right and left lobes

Round / ligamentum teres:

• within free edge of falciform lig.
• fibrous remnant of umbilical vein

Lig. Venosum:

• fibrous remnant of ductus venosus (connected left umbilical vein to IVC in foetus to allow blood to bypass liver)
• on posterior surface between caudate and left lobe

Coronary:

• on diaphragmatic surface
• connects liver to diaphragm (peritoneal reflection)
• demarcates bare area

Triangular ligaments:

• right and left extremities of coronary ligament
• demarcates bare area
• connects liver to diaphragm
• left: continuous with falciform anteriorly

Question 6

What are the peritoneal ligaments of the liver?

Answer 6

Lesser omentum
- connects liver to proximal duodenum and lesser curvature of the stomach

two components of lesser omentum:

a. hepatoduodenal lig: thickened portion of lesser omentum connecting liver to duodenum, encloses portal triad, lymph vessels and hepatic plexus
b. hepatogastric lig: remaining sheet like aspect of lesser omentum connecting liver to lesser curvature of stomach

Question 7

Which vessels supply blood to the liver?

Answer 7

1. Portal vein
   - supplies 70% of blood
   - formed by SMV and splenic vein (unite behind neck of pancreas)
   - carries nutrient rich but deoxygenated blood from stomach and intestines
2. Hepatic artery
   - supplies 30% of blood
   - branch of celiac trunk
   - conveys oxygenated blood

(vessels divide into right and left branches at porta hepatis)

Question 8

What is the nerve supply of the liver?

Answer 8

Hepatic plexus consists of:

• SNS fibres: T5-9 via celiac plexus
• PNS fibres: CNX Vagus

Question 9

Describe the histology of the liver:

Answer 9

• each lobe of the liver contains 100,000 lobules

Lobules:

• hexagonal
• functional unit of the liver
• contains plates of hepatocytes radiating outwards from a central vein

Portal tract:

• at each corner of the lobule
• contains: branch of hepatic artery, branch of hepatic portal vein, bile duct

Central vein:

• at centre of each lobule
• conveys blood that has moved from hepatic artery and portal vein through the lobule
• carries blood to hepatic vein

Question 10

Describe the direction of blood and bile flow through the lobules of the liver:

Answer 10

Blood:

• from hepatic artery and portal vein at the portal tract in the corner of each lobule
• through the lobule and to the central vein in the centre of the lobule
• central veins drain into hepatic vein

Bile:

• from central area
• via bile canaliculi
• to bile ducts in portal tracts at corners of lobules
• into hepatic ducts and into digestive system

Question 11

How does bile from the liver reach the digestive system?

Answer 11

From lobules:

• through bile caniculi
• into bile ducts at portal tracts at corners of lobules
• into right and left hepatic ducts
• unite to form common hepatic duct

Biliary tree:

• common hepatic duct unites with cystic duct to form bile duct
• bile duct unites with major pancreatic duct to form common hepatopancreatic duct
• drains into D2 via hepatopancreatic ampulla / sphincter of Oddi