Liver

Question 1

Liver overview

Answer 1

• Largest gland in the body
• 20% of oxygen consumption
• Receives 1.5L/min
• Intraperitoneal
• Protected by ribs 7-11
• Extends from Right hypochondriac to epigastrium

Question 2

Functions

Answer 2

1) Storage, metabolism and release of nutrients and some vitamins
2) Detoxification and elimination of drugs, toxins and metabolites
3) Removal of RBCs by Kupffer cells
4) Synthesis of proteins (clotting factors, albumin, lipoproteins)
5) Synthesis and secretion of bile
6) Role in immune function and clearance of intestinally absorbed bacteria

Question 3

Anatomical lobes

Answer 3

1) Right lobe
2) Left lobe
3) Quadrate lobe (functionally part of left lobe)
4) Caudate lobe (functionally an independent lobe)

Question 4

Functional lobes

Answer 4

• 8 functional lobes

- Based on distributions of branches of portal vein

Question 5

Porta hepatis

Answer 5

-Entrance/Exit point for portal triad in transverse fissure

Question 6

Ligaments of liver

Answer 6

1) Falciform ligament
- Derived from ventral mesogastrium
- Connects liver to anterior abdominal wall

2) Ligamentum teres (Round ligament of liver)
- Remnant of umbilical vein (carry oxygenated blood from placenta to liver)
- Thickening of free edge of falciform ligament
- Small para-umbilical veins may remain
- Quadrate lobe lies between ligamentum teres and gallbladder

3) Ligamentum venosum
- Remnant of ductus venosus (shunt blood directly from placenta to IVC – bypass underdeveloped liver)
- Caudate lobe lies between ligamentum venosum and IVC

4) Coronary ligament (anterior and posterior)
- Attaches the superior surface of liver to inferior surface of diaphragm
- Demarcates the bare area of liver

5) Triangular ligament (left and right)
- Formed from the union of anterior and posterior coronary ligaments at apex of liver
- Attaches right/left lobes of liver to diaphragm

Question 7

Bare Area of liver

Answer 7

• Resulted from massive growth of liver within ventral mesogastrium
• Fenced by anterior and posterior coronary ligament
• No peritoneum covering
• IVC passes through this area before piercing diaphragm (T8)

Question 8

Pringles Manouvre

Answer 8

Haemostat used to clamp the HEPATODUODENAL LIGAMENT (portal triad present) to ligate blood flow from hepatic proper artery and hepatic portal vein

Question 9

Blood supply of liver

Answer 9

1) Hepatic proper artery (25%)

2) Hepatic portal vein (75%)

Question 10

Hepatic portal vein

Answer 10

Tributaries:

1) Superior mesenteric vein
2) Splenic vein
3) Inferior mesenteric veins usually drains into splenic drain (1/3 population IMA drains directly into hepatic portal vein)

Question 11

Portal hypertension

Answer 11

• Obstruction (e.g. liver cirrhosis) causes pressure to rise in hepatic portal vein
• Can lead to:
  1) Splenomegaly – impeded blood flow in hepatic portal vein cause backup of blood into splenic vein and into spleen
  2) Caput medusae – impeded blood flow in para-umbilical veins cause blood to flow via epigastric veins (portosystemic anastomoses)

Question 12

Portosystemic anastomoses

Answer 12

Oesophageal veins

1) Portal –> Left gastric vein
2) Systemic –> Azygous vein

Peri-umbilical region

1) Portal –> Para-umbilical vein
2) Systemic –> Epigastric vein

Anal canal

1) Portal –> Inferior mesenteric vein
2) Systemic –> Middle and inferior rectal veins