Physiology of Liver Function

Question 1

What is the general role of the liver

Answer 1

to maintain blood : fill it with plasma proteins, glucose , clear it from waste like old RBC and ammonia

Question 2

What is the largest internal organ of the body

Answer 2

Liver

Question 3

What is a portal circulation

Answer 3

• blood flowing from arterial system to capillary bed to portal vessel to capillary bed then to venous system
• portal vessel transports blood from one capillary bed to another

Question 4

Where does blood for the liver come from ( organ )

Answer 4

small intestine

Question 5

What is the function of the Hepatic portal vein ( transports blood from what to what )

Answer 5

transports blood from small intestine capillary bed to liver capillary bed

Question 6

What is the relationship between the HPV and Hepatic Artery circulation

Answer 6

inversely related : HPV increases post prandially ( after meal )

Question 7

How does the liver maintain large blood flow with low pressure difference

Answer 7

by having a low resistance

Question 8

What will happen if the resistance to flow in blood increases in liver

Answer 8

necrosis, this happens in cirrhosis

Question 9

At rest what volume of blood does the liver hold

Answer 9

about 10%

Question 10

What supplies the liver blood

Answer 10

Hepatic portal vein and Hepatic artery

Question 11

What are portal triads and how many are there per lobule

Answer 11

• branches of hepatic artery , portal vein and bile duct

- 6

Question 12

What is the difference between blood and bile circulation direction

Answer 12

Blood circulates from the rim of lobules to inside

Bile circulates from inside, extending outwards to portal area

Question 13

What is the purpose of the liver’s cell arrangement ( extensive sheets )

Answer 13

increase surface area of blood and hepatocyte interaction

Question 14

The liver is the site of glucose ……… ( 4 things )

Answer 14

1- storage as glycogen
2- conversion of fructose and galactose to glucose
3- conversion of amino acids to glucose
4- derives glucose from fat in liver

Question 15

When does the liver increase or decrease blood glucose

Answer 15

Increase: fasting state

Decrease : after meal

Question 16

Under the influence of insulin what happens to glucose in liver

Answer 16

glycogen synthase converts glucose to glycogen

Question 17

Under the influence of Glucagon and Catecholamines in immediate fasting state what happens to glucose in liver

Answer 17

• glycogen is converted to glucose by phosphorylase

- Fat stores under lipolysis will break down and through gluconeogensis that will be converted to glucose

Question 18

With prolonged starvation what does the liver do

Answer 18

Further break down fat stores for glucose and breakdown protein

Question 19

Why is the liver considered a fat buffer ( 3 reasons )

Answer 19

• Forms cholesterol, phospholipids and lipoproteins in order for cholesterol and phospholipids to be able to be transported in blood
• Glucose and amino acids after meal will be converted and stored as fat
• in fasting state will break down fat stores into fatty acids which become ketones and glycerol which will become glucose

Question 20

What is the liver’s relationship with protein synthesis

Answer 20

• the liver is the main site of synthesis for all circulating proteins except gamma globulins
• synthesize plasma proteins from amino acids

Question 21

What is the liver’s relationship with protein degradation

Answer 21

Liver will convert ammonia to urea

Question 22

What vitamins are stored in liver / activated

Answer 22

• A, D, E and K, and 80% of B12

- vitamin D is hydroxylated in liver and then further in kidney

Question 23

What do Kupffer cells do to fat-soluble drugs

Answer 23

Get detoxified to be converted to water-soluble

Question 24

What is the composition of bile

Answer 24

Bile pigments, bile acids , alkaline medium , fat , water and other substances

Question 25

What is the function of bile

Answer 25

• excreting hemoglobin degradation by products (gives brown colour)
• Digestion of fats : bile acids line hydrophilic part of fats outside ( into micelles )

Question 26

Describe Haemoglobin breakdown ( Enterohepatic circulation )

Answer 26

• protein albumin is bound to bilirubin ( can’t be excreted in kidneys )
• bilirubin + glucuronic acid by glucuronyl transferase will make bilirubin diglucuronide which will be released to small intestine from hepatocyte through bile canaliculi
• bile will break it down to urobillinogens

Question 27

What happens when there is an excess of conjugated bile ( bile ducts backed up )

Answer 27

• bilirubin diglucuronide backs up into hepatocytes and gets into blood stream
• gets dissolved in water , appears in kidney and will appear in urine

Question 28

What happens when there is excess haemoglobin breakdown

Answer 28

• excess albumin bilirubin which can’t be filtered by kidneys or be broken down in blood won’t appear in urine

Question 29

What does it mean when there is bile in urine

Answer 29

• problem with excretion of bile

Question 30

What happens to urobilinogens and unconjugated bilirubin

Answer 30

• gets absorbed by small intestine and is sent back to liver to be made into bile

Question 31

What is cholelithiasis

Answer 31

• gallstones
• made of cholesterol crystals mostly or calcium bilirubinate
• role of gallbladder to concentrate bile doesn’t allow cholesterol to precipitate through

Question 32

What is jaundice

Answer 32

• yellow skin , sclera or mucous membrane
• excess bilirubin in blood ( prehepatic jaundice )
• decreased bilirubin uptake, binding or transport Ito canaliculie ( called hepatic jaundice )
• bile duct or gallbladder obstruction ( post hepatic jaundice )

Question 33

How to tell which type of jaundice it is

Answer 33

• looking if bilirubin is in urine and faeces

- look for dark urine and white faeces