Lecture 4: Structure and function of the liver

Question 1

Name some the liver functions?

Answer 1

• Amino acid, carbohydrate and lipid metabolism
• Storage of proteins, glycogen, vitamins and metals
• Plasma protein and enzyme synthesis
• Detoxification of endogenous and exogenous products
• Production of bile
• Immune functions

Question 2

The liver is located in which region of the 9 regions of abdomen

Answer 2

Right hypochondria region and epigastric region

Question 3

What are the arteries that supply the blood to the liver

Answer 3

Hepatic artery proper (25%) – supplies the non-parenchymal structures of the liver

Hepatic portal vein (75%) – supplies the liver with partially deoxygenated blood, carrying nutrients absorbed from the small intestine. This is the dominant blood supply to the liver parenchyma, and allows the liver to perform its gut-related functions, such as detoxification.

Question 4

Describe the venous drainage of the liver?

Answer 4

• Venous drainage of the liver is achieved through hepatic veins.
• The central veins of the hepatic lobule form collecting veins which then combine to form multiple hepatic veins.
• These hepatic veins then open into the inferior vena cava.

Question 5

What are the 3 structures that make up the portal triad?

Answer 5

1. Hepatic artery proper
2. Hepatic portal vein
3. Bile ducts

Question 6

The majority of the arterial supply to the liver comes from which vessel?

Answer 6

Hepatic portal vein (75%)

Question 7

Name the cells that make up the parenchyma tissue of the liver?

Answer 7

• The liver parenchyma is the functional tissue
• Hepatocytes make up the majority of the parcenchyma tissue

Question 8

The liver secretes bile into the duodenum via which vessel

Answer 8

The common bile duct

Question 9

Name the cells that make up the non-parenchyma tissue of the liver?

Answer 9

The non parenchymal cells of the liver include populations of:

• Cholangiocytes (epithelial cells)
• Sinusoidal endothelial cells
• Stellate cells
• Kupffer cells
• Intrahepatic lymphocytes

Combined they make up 40% of the cells in the liver.

Question 10

Name the components of bile

Answer 10

• Bilirubin
• Bile acids/salts
• Mucin

Question 11

Brief description of cirrhosis?

Answer 11

• Liver cirrhosis often results from chronic alcoholism or infection with hepatitis viruses.
• In this disease, portions of the liver are repeatedly destroyed and replaced at the expense of the hepatic architecture. Scarring disrupts the sinusoids and this results in the backup of blood in the portal vein and portal hypertension.
• Hepatocytes are still present, but there is a dense connective tissue bands that have formed throughout the sinusoids. As a result, the sinusoids would function less well at exposing the hepatocytes to the blood; the hepatocytes would do less of a good job at filtering the blood.

Question 12

Name the possible causes of cirrhosis

Answer 12

• Alcohol or alcohol-like
• Hepatitis incl. viral
• Biliary disease
• Unknown
• Haemochromatosis

Question 13

List the possible complications of cirrhosis

Answer 13

• Portal hypertension
  
  • Cirrhosis ↑ resistance to blood flow through liver thus ↑ pressure in portal circulation, causing:
    
    • Portal-systemic shunts and varices
    • Ascites - increase in free fluid in the abdomen
    • Splenomegaly - enlargement of the spleen
• Liver failure
• Hepatocellular (liver) cancer

Question 14

ALP is ________ in conditions causing _______ tract obstruction, with elevations proportional to the degree of obstruction.

Answer 14

Increased

Biliary

Question 15

________ is a group of enzymes found mainly in bone, liver, intestines and placenta.

Answer 15

ALP

Question 16

In post hepatic jaundice, ALT levels rise markedly.

A) True

B) False

Answer 16

B) False

Question 17

(ALT/AST) is greater than (ALT/AST) in metatastic disease of the liver.

Answer 17

A) AST

B) ALT

Question 18

Where is conjugated bilirubin is converted to urobilinogen.

Answer 18

In the small intestine

Question 19

________ transports unconjugated bilirubin to the liver.

Answer 19

Albumin

Question 20

_________ is responsible for the yellow coloring in jaundice.

Answer 20

Bilirubin

Question 21

Which factors are we testing for in the blood test used to assess liver function?

Answer 21

• Alanine transaminase (ALT)
• Aspartate aminotransferase (AST)
• Alkaline phosphatase (ALP)
• Gamma-Glutamyltransferase (GGT)
• Bilirubin
• Albumin
• Prothrombin time (PT)

Question 22

Describe the pattern of liver function test results for obstructive causes

Answer 22

High bilirubin

High ALP

Normal ALT

Question 23

A greater than 10-fold increase in ALT and a less than 3-fold increase in ALP suggests?

Answer 23

A predominantly hepatocellular injury

Question 24

A less than 10-fold increase in ALT and a more than 3-fold increase in ALP suggests ?

Answer 24

Cholestasis- post-hepatic obstruction in the biliary tree

Question 25

A raised ALP in the absence of a raised GGT is suggestive of?

Answer 25

Non-hepatobiliary pathology- particularly bone related disorders. Alkaline phosphatase is also present in bone and therefore anything that leads to increased bone breakdown can elevate ALP.

Question 26

A markedly raised ALP with a raised GGT is highly suggestive of?

Answer 26

Cholestasis- obstructive

Question 27

\_\_\_\_\_ bilirubin is water-insoluble and therefore doesn’t affect the colour of the patient’s urine. \_\_\_\_\_ bilirubin, however, can pass into the urine as urobilinogen, causing the urine to become darker.

Answer 27

A) Unconjugated bilirubin B) Conjugated bilirubin

Question 28

If bile and pancreatic lipase’s are unable to reach the bowel because of a blockage (e.g. in obstructive post-hepatic pathology), fat is not able to be absorbed, resulting in stools appearing \_\_\_

Answer 28

Pale

Question 29

The colour of the stools can be used to differentiate the causes of jaundice. **Normal urine + normal stools** is suggestive of which kind of cause of the jaudice? A) Pre-Hepatic B) Hepatic C) Post-hepatic

Answer 29

A) Pre-hepatic Normal urine: High level of Unconjugated bilirubin but this has no effect on the urine colour. Normal stool: bile and pancreatic lipase’s are able to reach the bowel

Question 30

The colour of the stools can be used to differentiate the causes of jaundice. **Dark urine + normal stools** is suggestive of which kind of cause of the jaudice? A) Pre-Hepatic B) Hepatic C) Post-hepatic

Answer 30

B) Hepatic High level of conjugated bilirubin causing the darkening of the urine

Question 31

The colour of the stools can be used to differentiate the causes of jaundice. **Dark urine + pale stools** is suggestive of which kind of cause of the jaudice? A) Pre-Hepatic B) Hepatic C) Post-hepatic

Answer 31

C) Post-hepatic (obstructive) _Dark urine_: high level of conjugated bilirubin _Pale stool_: Bile and pancreatic lipase cannot get into the bowel so the fat is not broken down causing pale stoole

Question 32

An isolated rise in bilirubin is suggestive of

Answer 32

A pre-hepatic cause of jaundice. Either: * Gilbert’s syndrome (most common cause) * Haemolysis

Question 33

ALT \> AST is seen in which condition

Answer 33

Chronic liver disease

Question 34

AST \> ALT is seen in which condition

Answer 34

Cirrhosis and acute alcoholic hepatitis

Question 35

Which part liver function test indiciates jaundice?

Answer 35

Bilirubin

Question 36

Which parts of the liver function test actually indicates the cause e.g. prehepatic, hepatic or post-hepatic

Answer 36

* ALT * AST * ALP * GGT

Question 37

Which part of the liver function test indicates how functional the liver is?

Answer 37

* Bilirubin * Albumin * Prothrombin time (PT)

Question 38

Fill in the blanks of this image of the liver

Answer 38