intro to liver and cirrhosis W5

Question 1

what defines segments of the liver?

Answer 1

venous drainage - branches of the hepatic vein

Question 2

parenchymal cells of the liver?

Answer 2

hepatocytes
bile duct epithelia (cholangiocytes)

Question 3

function of hepatocytes?

Answer 3

synthetic and metabolic activity

Question 4

function of bile duct epithelia (cholangiocytes)

Answer 4

contribute to bile secretion

Question 5

sinusoidal cells of the liver?

Answer 5

endothelial cells
Kupffer cells

Question 6

function of endothelial cells? (liver)

Answer 6

allow transfer of substances to hepatocytes

Question 7

function of Kupffer cells?

Answer 7

specialised tissue macrophages

Question 8

perisinusoidal cells of the liver?

Answer 8

stellate cells
pit cells

Question 9

function of stellate cells?

Answer 9

maintain homeostasis in sinusoids
involved in development of fibrosis

Question 10

function of pit cells?

Answer 10

NK cells of the liver

Question 11

features of protein metabolism in the liver?

Answer 11

catabolism of circulating protein/peptides
interconversion of amino acids
deamination of amino-acids allowing gluconeogenesis
synthesis of amino acids
catabolism of hepatic (stored) proteins in fasted state
protein synthesis

Question 12

what proteins are synthesised in the liver?

Answer 12

albumin
transport proteins
ferritin
protease inhibitors
CRP
AFP
complement
coagulation factors

Question 13

ammonia/ium metabolism in the liver?

Answer 13

absorbed from the gut
synthesised in the liver
detoxified in liver by conversion to urea in the urea cycle

Question 14

3 phases of drug metabolism?

Answer 14

1 - oxidation, reduction, hydrolysis. CYP450 in liver
2 - conjugation in cytoplasm of hepatocytes
3 - secreted into the bile

Question 15

constituents of bile?

Answer 15

bile acids
phospholipids
cholesterol
conjugated drugs
electrolytes
bilirubin

Question 16

what causes jaundice?

Answer 16

bilirubin

Question 17

where does bilirubin come from

Answer 17

breakdown product of haemoglobin

Question 18

which vitamins are stored in the liver in large amounts?

Answer 18

vitamin A, D, B12

Question 19

which vitamins are stored in the liver in small amounts? when are these rapidly depleted?

Answer 19

vitamin K, folate
depleted with decreased dietary intake

Question 20

what minerals are stored in the liver?

Answer 20

iron (stored in ferritin and haemosiderin)
copper

Question 21

immune regulation in the liver?

Answer 21

filters all blood from the gut
Kupffer cells phagocytose pathogens
supply of important chemokines/cytokines
priming T cell responses

Question 22

what is the precursor to cirrhosis? how does this occur?

Answer 22

fibrosis
chronic injury causes:
-inflammatory damage
-parenchymal cell death
-angiogenesis

Question 23

what types of chronic injury cause early fibrosis?

Answer 23

viral infection
alcohol
NASH
autoimmune disorders
cholestatic disorders
metabolic diseases

Question 24

what causes early fibrosis to develop into cirrhosis?

Answer 24

disrupted architecture
loss of function
aberrant hepatocyte regeneration

Question 25

how does hepatocyte injury lead to fibrosis?

Answer 25

hepatocytes injured, release substances, communicates to stellate cells, stellate cells activate macrophages leading to inflammation and fibrosis

Question 26

what can cirrhosis lead to

Answer 26

portal hypertension
ESLD

Question 27

what is cirrhosis?

Answer 27

development of regenerative nodules surrounded by fibrous bands in response to chronic liver injury

Question 28

causes of cirrhosis?

Answer 28

toxin/drugs - alcohol
metabolic (non alcohol related) fatty liver disease
viral hepatitis (B, C)
immune-mediated disorders
inherited diseases

Question 29

physical signs of cirrhosis? (maybe?)

Answer 29

jaundice
fever
loss of body hair
neuro - disorientation, drowsy, coma
ascites

Question 30

how to diagnose fibrosis/cirrhosis?

Answer 30

liver biopsy
serum markers
transient elastography

Question 31

liver biopsy features

Answer 31

gold standard
prone to sampling error, morbidity

Question 32

serum markers features

Answer 32

cheap widely available
non-specific, grey zone for intermediate fibrosis

Question 33

transient elastography features?

Answer 33

non-invasive, quick
machine costs, user experience, patient factors

Question 34

serum markers of liver function?

Answer 34

albumin
prothrombin time
bilirubin
platelets

Question 35

albumin features?

Answer 35

decreases in end stage liver disease due to decreased synthesis

Question 36

prothrombin time features

Answer 36

decreased synthesis of clotting factors leads to increased prothrombin time

Question 37

bilirubin features

Answer 37

increased in cirrhosis due to decreased clearance

Question 38

platelets features

Answer 38

decreased in cirrhosis
increased consumption due to splenomegaly
decreased thrombopoietin production