Liver

Question 1

What are the functions of the liver

Answer 1

Metabolism

Storage

Detoxification

Bile production

Filtration of blood

Endocrine functions

Question 2

What is the functional unit of the liver, what is found at each corner and what is found in the centre

Answer 2

Functional unit of the liver is the liver lobule - hexagonal shape

Triad of structures at each corner - portal vein, hepatic artery, bile duct

Central vein is found in centre of lobule

Question 3

What are the lobes of the liver

Answer 3

Left lobe

Right lobe

Quadrate lobe

Cuadate lobe

Question 4

What splits the left and right lobe apart

Answer 4

The falciform ligament

Question 5

What does bile consist of

Answer 5

Bile consists of bile salts and bile pigemnts in an alkaline solution

Question 6

What are bile salts

Answer 6

Bile salts are conjugated bile acids

Bile salts are more soluble at the duodenal pH than bile acids so conjugation is important for this

Question 7

What do bile salts do

Answer 7

Bile salts emulsify large globules of lipids to aid their digestion by lipases

Te increased SA for lipases means they can work faster

Question 8

What do bile salts do with the products of lipid breakdown

Answer 8

Bile salts create micelles around the products of lipid breakdown and help to transport hydrophobic molecules to the enterocyte membrane

Once at the membrane, the hydrophobic molecules are released and they diffuse into the enterocyte’s cytosol

Lipids are re-esterified -> packed into chylomicrons -> exocytosed from basolateral membrane of enterocytes -> enter lymphatics to enter circulation

Question 9

What are gallstones

Answer 9

Gallstones are stones that form in the gallbladder

They are formed from bile contents: cholesterol, bile pigments and phospholipids

Cholesterol and bile pigements form crystals which aggregate to form stones

Question 10

What are the complications of gallstones

Answer 10

Biliary colic

Acute cholecystitis

Acute ascending cholangitis

Acute pancreatitis

Question 11

What is biliary colic

Answer 11

RUQ pain caused by temporary obstruction of gallstone in cystic duct or common bile duct

Temporary obstruction -> no inflammation

Can be seen on USS and patient may have abnormal LFTs

Question 12

What is acute cholecystitis

Answer 12

Acute cholecystitis is caused by impaction of a stone in the cystic duct causing inflammatory features

Symptoms: RUQ pain and fever

Can have Murphy’s sign

Seen on USS as thick walled gallbladder

Question 13

What is acute ascending cholangitis

Answer 13

Infection of the biliary tree caused by stasis of fluid

Stasis is commonly due to CBD stone or other obstruction

Present with Charcot’s triad: RUQ pain, features of inflammation (fever) and jaundice

Question 14

What happens in acute pancreatitis

Answer 14

Have acinar cell injury and necrosis resulting in inflammatory response

Question 15

What is the presentation of acute pancreatitis

Answer 15

Epigastric pain radiating to the back

Vomiting

Cullen’s sign - umbilical brusing

Grey Turner’s sign - flank brusing

Question 16

What are the causes of acute pancreatitis

Answer 16

Gallstones

Ethanol

Trauma

Steriods

Mumps

Autoimmune

Scorpion sting

Hyperlipidaemia

ERCP - endoscopic retrograde cholangiopancreatography

Drugs

Question 17

What do liver function tests look at and when are the substances found at abnormal levels

Answer 17

Bilirubin - in any type of jaundice

Albumin - used to assess synthetic function of liver. If low suggests decreased liver function

ALT - high when hepatocytes are damaged

AST - high when hepatocytes are damaged

ALP - high in cholestasis

Question 18

How does the ratio of raised ALT to raised AST determine the type of liver damage

Answer 18

ALT > AST is acute liver damage

AST > ALT is chronic liver damage

Question 19

What is jaundice and how does it present

Answer 19

Jaundice - clinical manifestation of hyperbilirubinaemia

Presents as yellowed skin and/or sclera

Question 20

What are the types of jaundice and briefly describe what they are

Answer 20

Prehepatic - due to too much haem

Hepatic - reduced hepatocyte function

Post-hepatic - obstructive cause

Question 21

What is pre-hepatic jaundice

Answer 21

Jaundice caused by increased degradation of haemoglobin causing there to be too much haem for the liver to conjugate -> raised bilirubin levels

Ability to conjugate is normal as is excretory pathway

Raised bilirubin tends to be unconjugated

Babies may have pre-hepatic jaundice in first few days due to liver not being able to cope to begin with

Question 22

What are some causes of pre-hepatic jaundice

Answer 22

Haemoglobinopathies - sickle cell, thalassaemia, spherocytosis

Damage to RBCs causing haemolysis - e.g. Rhesus disease, malaria

Question 23

What is hepatic jaundice

Answer 23

Jaundice caused by decreased conjugating ability of the liver

Amount of bilirubin is normal and excretatory pathway is fine

Have mixture of conjugated and unconjugated bilirubin

Question 24

Name some causes of hepatic jaundice

Answer 24

Hepatotoxic drugs

Alcoholic or non-alcoholic liver disease

HBV/HCV or other infections

Paracetamol toxicity

Question 25

What is post-hepatic jaundice

Answer 25

Jaundice caused by an obstruction to the excretion pathway -> conjugated bilirubin cannot enter GI tract

Amount and conjugation of bilirubin is fine

Tends to be conjugated bilirubin

Question 26

How does urine and faeces change in post-hepatic jaundice

Answer 26

Urine becomes darker in colour as more bilirubin is excreted in urine

Stools become pale due to less bilirubin being excreted in faeces

Question 27

Name some causes of post-hepatic jaundice

Answer 27

Gallstones

Intrahepatic pathology compressing bile ducts - PBC, PSC, malignancy

Biliary stricture or malignancy of biliary tree

Pathology of pancreatic head - compresses common bile duct