Liver Anatomy

Question 1

Hepatostat

Answer 1

Unique regenerative capacity
Ensures that the liver to body ratio is maintained at 100 % - described as the hepatostat
Liver important to the metabolism of the human body
Increases in size in pregnancy and decreases following severe body weight loss
The hepatostat maintains the liver in proportion to body size and needs

Question 2

Gross Liver Anatomy

Answer 2

Anatomically four lobes: left, right, caudate and quadrate
Functionally considered as two lobes - left and right
Diaphragmatic surface: superior upper surface of the liver
Visceral surface: faces adjacent abdominal organs (faces downwards); the porta hepatis and gallbladder are located on this surface.

Question 3

The Caudate lobe

Answer 3

The Caudate lobe is next to the inferior vena cava

Question 4

The Quadrate lobe

Answer 4

is next to the gall bladder

Question 5

Liver Structure

Answer 5

Falciform ligament: separates the major right and left lobes and attaches the liver to the diaphragm and anterior abdominal wall, secures the liver the anterior abdominal wall

Round Ligament: Found at the lower edge of the falciform ligament

Gall bladder – accessory organ – pear shaped sac 7-10 cm long
Rests in a recess on the inferior, visceral surface of the liver

Question 6

The liver receives blood from two sources; the heart and GI tract

Answer 6

Hepatic portal vein delivers poorly oxygenated blood from the GI tract

Hepatic artery delivers oxygenated blood from the heart
Hepatic portal vein and hepatic artery divide into two to supply the left and right side of the liver

Question 7

Blood supplied to the liver via the

Answer 7

via the hepatic portal vein and hepatic artery

Question 8

Aorta supplies the abdominal aorta to the celiac trunk into

Answer 8

the hepatic artery to supply blood to the liver
Well oxygenated blood

Question 9

Hepatic portal vein drains blood from the capillary beds

Answer 9

of the GI tract including spleen and pancreas.
Nutrient rich but poorly oxygenated blood
The sources of blood mix within the liver and then drain into the central vein which empties in to the Hepatic vein and ultimately into the inferior vena cava to return blood back to the heart

Question 10

What cells are found in the liver?

Answer 10

Diverse functions of the liver are performed by hepatocytes.

Hepatocytes are 60 % of the cells found in the liver (and 80 % of the liver mass).

Other cell found in the liver:

Endothelial cells, stellate cells, biliary epithelial cells (cholangiocytes), Kupffer cells and other immune cells

Question 11

Liver ultrastructure

Answer 11

The liver is formed of repeating anatomical units called hepatic lobules
Blood flows in the hepatic lobules from the edge via portal trials
Inward blood flow in the portal trials from the hepatic portal vein and the hepatic artery
Blood flows through the hepatic lobule via sinusoidal vessels and then drains into the central vein
The central vein empties into the hepatic veins and then to the inferior vena cava

Question 12

Liver ultrastructure- bile

Answer 12

Bile flows in the opposite direction through the liver lobule

Bile flows down bile canaliculi towards the portal triad where it flows into bile ductules

From the bile ductules it is transported towards the gastro-intestinal tract and gall bladder

Blood flows from the portal triad to the central vein

Bile flows in the opposite direction towards the portal triad

Question 13

Hepatocytes (Liver cells)

Answer 13

Hepatocytes are specialized polarized cells (one side of the cell looks different to the other side – asymmetry in structure)

Hepatocytes separate sinusoidal blood from the canalicular bile

Basolateral membrane faces the liver sinusoidal endothelial cells

Apical membrane faces the bile canaliculi jointly with the directly opposing hepatocytes

Question 14

What is bile?

Answer 14

Exocrine secretory product of the liver
Bile contains HCO3-, cholesterol, lecithin (a phospholipid), bile pigments and bile salts
Bile salts are important for the absorption of water insoluble fats
Stored and concentrated in the gall bladder
Released during meals

Question 15

Liver lobule

Answer 15

Counter current flow of blood and bile (opposite directions)
Bile ducts lined by hepatocytes
Blood sinusoid lined by single layer of fenestrated endothelial cells
Portal field (portal triad) composed of portal hepatic vein, portal artery and bile duct
Central vein drains to the vena cava

Question 16

Fenestrated sinusoidal endothelial cells

Answer 16

Filter between the lumen of the hepatic sinusoid and hepatocytes.
Minimize any barrier for the bi-directional transfer of small or soluble substrates between blood and the extracellular space of Disse

Question 17

Kupffer cells

Answer 17

80 – 90% tissue macrophages in the liver; also known as stellate macrophages
Discovered by pathologist C von Kupffer
Reside in the lumen of the sinusoids of the liver, adherent to endothelial cells
Important role in host defence

Question 18

Stellate cells

Answer 18

Stellate cells are found in the subendothelial space between the basolateral surface of hepatocytes and anti-luminal side of the sinusoidal endothelial cells
spindle-shaped cell bodies with oval or elongated nuclei
single stellate cell usually surrounds more than two nearby sinusoids
Thought to be involved in liver fibrosis

Question 19

Bile duct circulation

Answer 19

Bile is transported down bile canaliculi in the liver
The bile canaliculi empty into bile ductules and then bile ducts
Empties into the hepatic ducts
Bile then directly enters the duodenum or diverted to the cystic duct into the gall bladder
The gall bladder concentrates and stores bile ready for use

Question 20

Gall bladder

Answer 20

Pear shaped, 7 -10 cm long
Fundus: wide end of gall bladder and projects from the inferior border of the liver
Body: contacts the visceral surface of the liver
Neck: narrow and tappered; makes an S bend into the cystic duct. Internally the mucosa spirals into the spiral fold that keeps the cystic duct open.

Question 21

Bile Ducts

Answer 21

Cholangiocytes are epithelial cells that line the intra- and extra-hepatic ducts of the biliary tree
Modifies bile to generate ductal bile
Cystic Duct is approx 4 cm long
The cystic duct connects the neck of the gall bladder to the common hepatic duct