W2: Liver

Question 1

hepatic portal vein role

Answer 1

to take nutrients absorbed from small intestine to liver to be processed

Question 2

what are rbcs broken down into + by what

Answer 2

heme + globin
by macrophages

Question 3

heme broken down into

Answer 3

bilirubin + iron

Question 4

how is bilirubin transported by the liver + why

Answer 4

bound to albumin - to incr its solubility

Question 5

what makes urine yellow + faeces brown

Answer 5

urine converted to urobilin
faeces converted into stercobilinogen

Question 6

7 liver functions

Answer 6

• Catabolism + excretion of bilirubin
• Mainten. of glucose homeostasis
• Metabolism of cholesterol + triacylglycerols
• Prod of some clotting factors
• Detoxification of drugs
• Catabolism of ‘amino’ (NH2) groups of AAs to urea
• Protein syn: albumin & globulins (except immunoglobulins)

Question 7

3 tests for liver damage + how its indicated

Answer 7

indicated by high levels of:

• ALT (alanine aminotransferase)
• AST (aspartate aminotransferase)
• ALP (alkaline phosphatase)

bc when damaged they leak out into blood

Question 8

3 liver function tests

Answer 8

• Total bilirubin
• Albumin
• GGT (gamma glutamyl transpeptidase)

Question 9

3 strictly liver function tests

Answer 9

• Bilirubin
• Albumin
• Prothrombin time (clotting test)

Question 10

what are ALT + AST + when are they abundant

Answer 10

Enzymes involved in the transfer of amino groups. Important in AA metabolism.
Correct name = aminotransferases
ALT & AST abundant in hepatocytes
AST also abundant in skeletal muscle cells + rbcs
Released into bloodstream when hepatocytes are damaged

Question 11

ALP: found where, function, isoenzymes found in which organs, enzyme blood levels incr when

Answer 11

• enzyme found in hepatocyte mems close to bilary ducts
• function not fully understood
• isoenzymes in; liver, bone, intestines, placenta
  -incr when pressure inside bilary ducts incr

Question 12

GGT: found where, function, enzyme blood levels inc rwhen

Answer 12

• enzyme found in hepatocyte mems close to bilary ducts
• transfers gamma-glutamyl groups btwn peptides
• when pressure inside bilary duct incr
  OR
• when enzyme syn induced by: alc/ some antiepileptic drugs

Question 13

albumin: synth where, carrier of, function,

Answer 13

• liver
• proteins, peps, drugs in blood
• maintains oncotic pressure in blood vessels

Question 14

high or low conc of serum albumin in severe liver disease

Answer 14

low

Question 15

low albumin suggests…

Answer 15

patient has disease but not specific enough to identify which
further testing needed

Question 16

bilirubin: conjugated in liver with, excreted in,

Answer 16

• glucuronic acid
• bile

Question 17

lab measures ___ bilirubin (adults)
normal values unconjugated vs conjugated

Answer 17

• total
  uncon: 98%
  con: 2%

Question 18

prothrombin time

Answer 18

• clotting test: assesses clotting factors syn by liver
• gives an international normalised ratio (INR)
• prolonged clotting time in moderate/severe liver disease

Question 19

ammonia: measured + not measured in

Answer 19

• only in neonates w severe illness, irritability, low consciousness level
  -Not measured in adults w liver disease as levels do not correlate w severity of disease

Question 20

glucose high or low in severe liver disease

Answer 20

low

Question 21

main categories of liver disease

Answer 21

• hepatitis
• cholestasis
  -mixed hep + chole
• tumours + other infiltrative diseases
• alcohol liver disease

Question 22

what does hepatitis + cholestasis mean

Answer 22

hep = inflamm of liver
cholestasis = bile flow impairment

Question 23

infectious types of hepatitis

Answer 23

A, B, C
acute or chronic

other viruses - Epstein Barr virus causing glandular fever 9mild hep)

Question 24

2 drugs/ toxins that can cause hep

Answer 24

alc
para overdose

Question 25

2 other causes of hep

Answer 25

autoimmune ischaemic - secondary to acute shock (causes rapid drop to BP)

Question 26

ALT & AST usually x 20-50 ULN indictates

Answer 26

- acute hepatitis types A, B, C, - secondary to severe ischaemia - severe paracetamol overdose/ other overdoses

Question 27

ALT & AST x 2 -10 ULN indicates

Answer 27

- glandular fever, autoimmune hepatitis & chronic hepatitis

Question 28

other abnormalities

Answer 28

incr serum ALP 2 x ULN incr serum bilirubin (depends on severity) Usually 3-4 x ULN In severe cases, jaundice appears (usually bilirubin > 4-5 x ULN) Both unconjugated and conjugated

Question 29

other abnormalities (2)

Answer 29

Bilirubin appears in urine (brown colour). Not normally present Clotting may be impaired. incr INR (depends on severity)

Question 30

effects of massive hep (fulminant)

Answer 30

- Hypoglycaemia - Hypoalbuminaemia - Severe clotting impairment - V high bilirubin - Extremely high ALT & AST - V high ammonia -> altered level of consciousness

Question 31

what is urgently given to prevent liver damage after paracetamol overdose

Answer 31

N-acetylcysteine

Question 32

where can cholestasis occur

Answer 32

anywhere from liver canaliculus to duodenum

Question 33

2 types of obstruction + examples

Answer 33

partial or complete gall stones extra-hepatic cancer causing obstruction (pancreas) which presses on bile duct so bile can’t be removed from liver (cholestasis can be caused by other diseases affecting billary tree)

Question 34

how is cholestasis detected?

Answer 34

cholestatic pattern - incr back-pressure on cells of canaliculi + then hepatocytes - big incr ALP (depends on severity) Twice ULN – 20 x ULN - ALT & AST slightly raised (but can be 3-4 x ULN) - big incr bilirubin 5 – 15 x ULN, 95% conjugated - bilirubin appears in urine (brown colour) not normally present

Question 35

how is complete obstruction cholestasis detected

Answer 35

stool is pale as bile pigments don't reach gut

Question 36

what is mixed hepatitis/ cholestasis

Answer 36

damage to both hepatocytes + cells of bile duct

Question 37

causes of mixed hep/chole

Answer 37

During sepsis Drugs - immunosuppressants Autoimmune liver disease Any hepatic/ cholestatic disorder already mentioned

Question 38

effect of mixed H+C on aminotransferases + ALP

Answer 38

mildly-moderately raised

Question 39

indicator of autoimmune hep

Answer 39

- incr antinuclear antibodies (Abs that bind to nucleus of own cells) - incr smooth muscle antibodies

Question 40

types of liver tumours

Answer 40

- Benign or malignant - Single or multiple nodules/masses. Usually infiltrative - Primary or secondary (metastases from tumour in different part of body)

Question 41

in liver function test there's big incr in which enzyme to detect advanced liver cancer

Answer 41

ALP

Question 42

what's raised in hepatocarcinoma

Answer 42

alpha-feto-protein (AFP) as this is prod by tumour in liver of foetus

Question 43

effects of chronic alc intake on GGT + red cell vol

Answer 43

- incr GGT due to incr enzyme syn - incr red cell vol (macrocytosis)

Question 44

how long for GGT to go back to normal if individual stops alc intake

Answer 44

3-4 weeks

Question 45

disadvs of GGT testing

Answer 45

- not sensitive - not specific as levels of GGT can be incr in most types of liver disease

Question 46

Other consequences of chronic alcohol intake

Answer 46

- Fatty liver: deposition of fat in liver, associated w raised serum triaylglycerols -> (not damaging but can lead to) inflamm of liver, fibrosis of liver -> liver cancer - Raised plasma urate - Acute hepatitis (acute alcohol intake) - Liver cirrhosis (fibrosis of the liver) in heavy drinkers. Can progress to malignancy.

Question 47

why does MCV take longer to normalise

Answer 47

bc rbc half life = 120days