Liver Function

Question 1

What are the three basic functions of the liver?

Answer 1

Storage and filtration of blood
Secretion of bile
Various metabolic functions

Question 2

What is the functional unit of the liver?

Answer 2

Lobule

Question 3

How many lobules in the liver?

Answer 3

About 100,000

Question 4

Briefly describe the structure of a lobule

Answer 4

Central vein surrounded by:

• hepatic cellular plates containing hepatocytes
• bile canaliculi
• sinusoids
• portal triad (duct, artery, portal vein)

Question 5

What two types of cells line sinusoids?

Answer 5

• Endothelial cells

- Kupffer cells

Question 6

What are Kupffer cells?

Answer 6

Large phagocytic cells

Remove 99% of bacteria from portal blood stream

Question 7

What is the name given to the space between the sinosoids and the hepatocytes?

Answer 7

Space of Disse

Question 8

What which two vessels does blood enter the liver?

Answer 8

Portal vein

Hepatic artery

Question 9

What role does the liver play in hemorrhage?

Answer 9

Releases stored blood from sinusoids

Question 10

What happens to blood flow in cirrhosis?

Answer 10

Increase in hepatic vascular resistance

Question 11

From where does portal blood come?

Answer 11

Intestines, so contains intestinal bacteria

Question 12

What is the pathway of bile flow?

Answer 12

Hepatocytes
Bile canaliculi
Terminal bile ducts
Common bile duct
Intestine

Question 13

How much bile is secreted per day?

Answer 13

800-1000ml

Question 14

What is the function of the gallbladder?

Answer 14

Concentrate bile (up to 12 fold)

Question 15

What hormone acts on the gallbladder to release bile?

Answer 15

Cholecystokinin (stimulated by fat in food)

Question 16

What are the four main components of bile?

Answer 16

Bile salts
Bilirubin
Cholesterol
Electrolytes

Question 17

What are bile salts made of?

Answer 17

Metabolites of cholesterol and amino acids (usually glycine)

Question 18

What are the two main functions of the bile salts?

Answer 18

Break down fat globules (emulsifying)

Absorb lipids from the intestine

Question 19

What is the name of the complex that bile salts form with lipids, and what is their purpose?

Answer 19

Micelles

Make lipids soluble

Question 20

What happens when lipids are not properly absorbed?

Answer 20

ADEK vitamins not properly absorbed

Vitamin K deficiency leads to blood coagulation factor (e.g. prothrombin, fibrinogen) deficiency

Question 21

What is enterohepatic circulation?

Answer 21

Recirculation of bile salts - reabsorbed from intestine into portal vein

Question 22

How does bilirubin reach the liver?

Answer 22

Old red blood cells release haemoglobin and are phagocytosed
Heme rings open to give 4 pyrrole compound –> bile pigments
Biliverdin –> bilirubin released into plasma where it combines with albumin
Bilirubin-albumin complex combines with Y-protein in liver cells

Question 23

To what compound is bilirubin-albumin metabolised?

Answer 23

Bilirubin glucoronide - excreted into bile ducts

Question 24

What is jaundice?

Answer 24

High free and conjugated bilirubin

Question 25

What causes jaundice?

Answer 25

Haemolytic - increased destruction of red blood cells | Obstructive - Obstruction of bile ducts or damage to liver cells

Question 26

What are gallstones?

Answer 26

Precipitation of insoluble cholesterol in bile system

Question 27

What are the causes of gallstones?

Answer 27

Too much water absorbed from bile Too much bile salt absorption Too much cholesterol secreted into bile Inflammation of gallbladder epithelium

Question 28

What are the carbohydrate metabolic functions of the liver?

Answer 28

- Storage of glycogen - Conversion of galactose to glucose - Conversion of amino acids to glucose - Formation of intermediates for metabolism - Control of blood glucose concentration

Question 29

What are the fat metabolic actions of the liver?

Answer 29

- B-oxidation of fatty acids to supply energy - Formation of lipoproteins - Formation of cholesterol and phospholipids - Conversion of carbohydrates and proteins to fats

Question 30

What does the liver do to amino acids?

Answer 30

De-amination before conversion to fat/carb/energy | Synthesis of non-essential amino acids

Question 31

What is the function of urea?

Answer 31

Removal of ammonia from gut bacteia

Question 32

What results from ammonia build up?

Answer 32

Hepatic coma

Question 33

What is the relationship between plasma proteins and the liver?

Answer 33

The liver makes 85% of them

Question 34

How is iron stored in the liver?

Answer 34

As ferritin bound to apoferritin