Normal Liver Function Flashcards

(49 cards)

1
Q

What is the liver made up of?

A

Lobules

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2
Q

What does a liver lobule look like and what does it contain?

A
Hexagon made by Hepatocytes
Central vein in the middle.
Portal triads on each side
Each triad contains:
Bile duct 
Hepatic artery
Hepatic portal vein

Sinusoids meet in the middle

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3
Q

What are the functions of the liver?

A

Metabolism
Synthetic Function
Biliary circulation
Storage

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4
Q

What does the liver do?

Carbohydrate metabolism

A

Liver is an ‘altruistic’ organ — releases glucose into the bloodstream (compare with skeletal muscle) Glycogen storage and breakdown
Gluconeogenesis

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5
Q

What does the liver do?

Protein metabolism

A

Transamination

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6
Q

What is Transamination

Step by step

A

Amino groups are removed from amino acids and transferred to acceptor keto-acids to generate the amino acid version of the keto-acid and the keto-acid version of the original amino acid. They swap groups
Then oxidative deamination occurs.

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7
Q

How is ammonia removed from the liver?

A

In the urea cycle to make urea which is removed in the urine

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8
Q

What does the liver synthesise

A

Albumin
Clotting factors
Acute phase proteins - CRP

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9
Q

What is albumim?

A

Makes up 50% of plasma proteins
Main factor in maintaining ONCOTIC PRESSURE
Also acts as a carrier protein for calcium, bilirubin

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10
Q

What does Low albumin cause?

A

PERIPHERAL OEDEMA

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11
Q

What causes hypoalbuminaemia

A

iver disease, nephrotic syndrome, malnutrition, burns

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12
Q

What is the Ampulla of Vater

A

Where the biliary system goes into the second part of the duodenum

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13
Q

How are red blood cells broken down

A

Into-
_Haem which is broken into-
Biliverdin Bilibrubin
Iron

_Globin which is broken into-
Amino acids

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14
Q

What splits haem into its organic material

A

Haemoxygenase

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15
Q

What breaks down biliverdin?

A

Biliverdin reductase

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16
Q

What is the difference between biliverdin and bilirubin in terms of solubility

A

Biliverdin is soluble in water

bilirubin is insoluble

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17
Q

How is bilirubin transported to the liver?

A

Bound to albumin (carrier protein)but it is unconjugated
when it reaches the liver albumin leaves
bilirubin enters liver by facilitated diffusion
bilirubin conjugates with glucuronic acid by an enzyme where then it can be used.

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18
Q

Where are red blood cells broken down?

A

In reticuloendothelial system

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19
Q

What enzyme conjugates bilirubin with glucuronic acid

A

UDP glucuronyl transferase

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20
Q

What happens to bilirubin after it has been conjugated

A

Metabolised to form urobilinogen
Some is absorbed into the portal blood and then to the kidneys
In kidneys it is further metabolised into urobilin
Some is further metabolised into stercobilin

21
Q

What is stercobilin used for?

A

Colouring faeces

22
Q

What happens if too much bilirubin is produced?

A

Increase in unconjugated bilirubin as liver cant handle amount and so can’t conjugate all of it

23
Q

What can cause too much bilirubin being produced

A

Haemolysis

Enzyme isn’t functioning properly

24
Q

What problems can happen in the liver and what results from it?

A

Too much bilirubin- excess unconjugated bilirubin
Dysfunctional/No/Less Enzyme-excess unconjugated bilirubin
Obstruction in the biliary system- excess conjugated bilirubin/ No urobilinogen in faeces

25
What is cholestasis and what is it caused by?
Pale faeces | Obstruction of the biliary system
26
What are isoenzymes
Catalyse the same reactions but in different places
27
What can cause rise in alkaline phosphate levels?
Liver problems Bone problems In pregnancy problems
28
What does it mean if the aminotransferase levels are up?
Damage to liver cells
29
What does it mean if the alkaline phosphate levels are up?
Problems in the biliary system
30
What are bile salts synthesised from
Cholesterol
31
What do bile salts do?
Emulsify lipids prior to intestinal absorption
32
What are bile acids synthesised by?
Hepatocytes
33
What are the primary bile acids?
Cholic acid | Chenodeoxycholic acid
34
What are primary bile acids metabolised by?
intestinal bacteria
35
What are primary bile acids metabolised into?
secondary bile acids
36
What are the secondary bile acids?
deoxycholic and lithocholic acid
37
Where are secondary bile acids used? And what do they form?
In intestine | negatively charged bile salts
38
Where are bile salts recirculated?
In the Enterohepatic circulation
39
What are bile salts reabsorbed as?
Urobilinogen | Stercobilin
40
What are keto acids?
Like amino acids but instead of an amino group a ketone group sits there
41
What enzyme is used to perform transamination?
Transaminase
42
What is transaminase also known as?
aminotransferase
43
What does the oxidative deamination do and why is it done?
This changes the amino acid back into a keto acid. NAD+ into NADH + NH3 is applied and so NADH is used in respiration
44
How are aminotransferases used clinically
These enzymes should be in the hepatocytes, not the bloodstream. If we test for aminotransferases in the blood and it is positive there is a problem
45
What is used as a marker when clinically testing the blood to check liver damage
Use alanine aminotransferase (ALT)
46
What does a rise in ALT be a sign of
hepatocellular damage
47
How can aminotransferases be in the blood?
Hepatic portal system is very close to the lobules of the liver and can be anastomosed
48
What was previously used as a marker when clinically testing the blood for liver damage
AST- aspartate aminotransferase
49
What was the problem with aspartate aminotransferase and why is alanine transferase good?
ALT- Sensistive AND specific AST- Sensitive NOT specific Found in cardiac cells also