2. Liver Flashcards by Kieron Young

Where is the liver located?

URQ, extends across to the ULQ

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How many lobes is the liver divided into?

Left, caudate, quadrate and right

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What is the Falciform ligament?

Divides the liver into two lobes and connects it to the diaphragm

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What are the blood vessels of the liver?

Hepatic portal vein, Hepatic artery and Hepatic vein

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What is the couinaud classification?

This is where the liver is able to be divided into 8 functionally independent segments. Each segment can be resected without damaging those remaining.

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What is found centrally in the segment of each couinaud segment?

Portal vein, hepatic artery and bile duct

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What is found peripherally in the segment of each couinaud segment?

Hepatic vein

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Number the 8 segments of the liver.

See diagram

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What kind of blood supply does the liver have?

Dual blood supply: 20% hepatic artery, 80% hepatic portal vein
Blood from the liver drains onto the IVC via the hepatic vein

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What is the purpose of the hepatic portal vein?

The vein which drains the intestines. Nutrients absorbed from the intestines go straight to the liver - nutrient rich

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What is the purpose of the hepatic artery?

Supplies oxygenated blood and nutrient to the liver

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What makes up a liver lobule

Hexagonal structure where each corner has a branch of the hepatic portal vein, branch of the hepatic artery and branch of the bile duct. Bile leaves the liver with the flow being opposite to the branches of the hepatic portal vein and artery which drain towards the central vein.

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What is the name for the collection of the hepatic portal vein, hepatic artery and bile duct?

Portal tract/triad

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Describe the blood flow of the hepatic portal vein and artery

They join together and flow towards the central vein through sinusoids

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What makes up 80% of the weight of the liver?

Hepatocytes

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List the cell types in the liver

Hepatocytes, Endothelial cells, cholangiocytes, Kupffer cells, Hepatic stellate cells

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Where do the kupffer cells lie?

They lie within the sinusoids

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What are kupffer cells?

They are immune cells, like macrophages (phagocytosis). Protects the liver from anything pathogenic that may be carried in the sinusoids originating from the intestinal veins.

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What lines the sinusoids?

Endothelial cells

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Where do the stellate cells lie?

In the space between the hepatocytes and the endothelial cells

Describe the structure of a hepatocyte

A large round cell with pale and rounded nuclei. Hepatocytes form cords (sheets) radiating from a central vein.

What are acinus?

A functional unit which essentially connects two central veins together. This unit of hepatocytes is divided into zones dependent on proximity to arterial blood supply. Zone 1 is closest and Zone 3 is furtherest from the portal triad.

Which zone is most susceptible to ischaemia?

Zone 3 because it is furthest away from the blood supply

Which zone is most susceptible to viral hepatitis?

Zone 1 because it more exposed to viral infections, closer to blood supply

What cell produces Bile?

Heptaocytes

What are the sinusoidal endothelial cells?

Fenestrated - allows lipid and other large molecule movement to and from hepatocytes

What are hepatic stellate cells?

Vitamin A storage. At times of stress the kupffer cells secrete cytokines which activate stellate cells. The stellate cells increase production in extracellular matrix leading to fibrogenesis.

What does the liver store?

Any glucose taken up is stored as glycogen and break down of these stores will occur when there is a low glucose concentration.

The liver can supply the body with glucose from glycogen stores for how long?

24 hours

What is the Cori Cycle?

When the muscle cell undergoes anaerobic respiration pyruvate is converted to lactate. The liver will then convert this lactate back into pyruvate which can be used to produce glucose via gluconeogenesis. The glucose produced can then be fed back into glycolysis in the muscle cell.

What type of amino acids does the liver produce?

non-essential amino acids

What does the liver use amino acids for?

plasma proteins, clotting factors and lipoproteins

How does the liver produce non-essential amino acids?

Transamination e.g Alanine + a-ketoglutarate --> Pyruvate + Glutamate

Which three amino acids can be used to make all the non-essential amino acids?

a-ketoglutarate, pyruvate, oxaloacetate

What is deamination?

Removal of an amino group

Describe the process of deamination with the liver

The alanine is moved across into the liver and transaminated to produce glutamate. The glutamate is broken down producing urea, which is then passed to the blood. The pyruvate is converted to glucose which can enter the muscle for glycolysis.

How much energy is required for the deamination of glutamate?

+4 ATP

How much energy is required for the conversion of pyruvate to glucose?

+6 ATP

Describe triglyceride metabolism

Triglycerides are broken down into fatty acids. The fatty acids are moved to the liver. B-oxidation converts the fatty acids into acetyl CoA which can enter the TCA cycle in the liver. The acetyl CoA can also be taken and converted to ketone bodies; acetoacetate. This ketone body can then enter the blood the travel to other cells where i can be converted back into acetyl CoA.

How does the liver synthesis lipoproteins?

Glucose can be converted to glycerol, fatty acids and cholesterol. The gylcerol and fatty acids can be used to produce Tri-acyl glycerol, which when combined with apoproteins, phospholipids and cholesterol produces lipoproteins.

What are VLDLs?

Very low density lipoprotein - used to transport fatty acids to tissues

What are HDLs?

Empty lipoproteins - used to pick up excess cholesterol

What are LDLs?

Transports cholesterol to tissues

What vitamins does the liver store?

Stores the fat soluble vitamins A, D, E, K, B12. Vitamin K store is small because it is essential for blood clotting.

What metals are stored in the liver?

Iron and Copper

How does the liver detoxify substances?

P450 enzymes Phase 1 - make it more hydrophilic Phase 2 - attach water soluble side to chain to make it less reactive

What are cholangiocytes?

They line biliary structures - essentially bile duct epithelial cells

What are VLDLs converted to?

LDL

What do VLDLs have a high component of?

Triacylglycerol