Liver Function & Disease

Question 1

Portal vein

Answer 1

brings nutrients & 75% of blood supply

Question 2

Hepatic artery

Answer 2

brings 02 & supplies 25% of blood to liver

Question 3

Hepatocytes

Answer 3

80% of liver space, do liver jobs & also facilitate regeneration

Question 4

Kupffer cells

Answer 4

macrophages that line sinusoids, phagocytic cells engulf bacteria, toxins, debris etc

Question 5

Stellate cells

Answer 5

contain lipid droplets, when they are activated the lipids begin to deposit in the sinusoid & fibrotic tissues -> cirrhosis

Question 6

Liver functions (4)

Answer 6

excretory & secretory
synthesis
detoxification & drug metabolism
storage

Question 7

waste products & where they go

Answer 7

bilirubin, bile acids, cholesterol, bile pigments & other wastes get excreted in the bile that goes to the gall bladder & then small intestine

Question 8

Heme degradation

Answer 8

heme from hemoglobin is degraded to biliverdin & then to bilirubin
this is insoluble & cannot be removed by kidneys

Question 9

unconjugated bilirubin transporter

Answer 9

albumin to the liver sinusoidal spaces

Question 10

location of bilirubin conjucation & carrier

Answer 10

bilirubin is carried by ligandin in hepatocytes to ER where bilirubin is conjugated

Question 11

conjugation enzyme for bilirubin

Answer 11

UPD-glucuronyl transferase

Question 12

conjugated bilirubin path

Answer 12

water soluble & most leaves the hepatocyte via bile ducts to go to gall bladder -> common bile duct -> small intestine
help in the emulsification of fats & broken down by gut bacteria to form urobilinogen then urobilin

Question 13

reabsorbed urobilinogen goes where?

Answer 13

reabsorbed urobilinogen from the small intestine can go from the plasma to the urine through the kidneys

Question 14

major exit route for bilirubin

Answer 14

mostly out via feces

Question 15

Malloy-Evelyn

Answer 15

uses diazo reaction & 50% methanol accelerator to measure serum/plasma bilirubin
cannot use plasma specimen bc alcohol will precipitate proteins

Question 16

Jendrassik-Grof

Answer 16

uses diazo reaction & caffeine-benzoate-acetate accelerator to measure serum/plasma bilirubin

Question 17

total bilirubin

Answer 17

includes conjugated bilirubin & unconjugated bilirubin

Question 18

conjugated bilirubin methods

Answer 18

does not use caffeine or alcohol (only measures what is already soluble)

Question 19

reasons why J-G method is preferred

Answer 19

not affected by pH
insensitive to 50x change in protein
maintains optical sensitivity even @ low [bilirubin]
minimal turbidity & relatively constant serum blank
not affected by hemoglobin up to 759mg/dl

Question 20

specimen for bilirubin

Answer 20

free of hemolysis & lipemia

KEEP AWAY FROM LIGHT

Question 21

how does the liver stabilize glucose concentrations

Answer 21

absorbs glucose for own use
circulates glucose for peripheral tissues
stores glucose as glycogen
can make glucose from non-CHO sources

Question 22

lipid synthesis by liver

Answer 22

makes VLDL, cholesterol

removes lipids from circulation= chylomicrons & HDL

Question 23

protein synthesis by liver

Answer 23

synthesizes proteins other than immunoglobulins
makes coag proteins, albumin, globulins etc
stores amino acids for use or degradation

Question 24

Liver detoxification

Answer 24

liver 1st pass effect allows liver to remove toxic/foreign compounds before they enter blood & circulate
removes bilirubin & ammonia
uses oxidation, reduction, hydrolysis, hydroxylation, carboxylation, demethylation via CYTOCHROME p-450 isoenzymes

Question 25

jaundice

Answer 25

observable when bilirubin >3.0 mg/dl prehepatic : increased RBC breakdown; major increase in unconjugated hepatic- usually increase in conjugated post hepatic- usually obstruction of bile duct (both elevated)

Question 26

Gilbert's disease

Answer 26

not pathologic, elevation in unonjugated bilirubin intermittent increase in unonjugated bili in ABSENCE OF HEMOLYSIS reduction of UDP-glucuronyl transferase activity ~30%

Question 27

Crigler-Najjar syndrome

Answer 27

2 types of UDP defect type1: no UDP enzyme: fatal type2: partial absence of enzymes

Question 28

Dubin-Johnson syndrome

Answer 28

increased conjugated bilirubin | defect in MDR2/cMOAT or liver ability to remove & excrete conjugated bilirubin & cannot leave the liver

Question 29

Rotor syndrome

Answer 29

unknown defect increase in conjugated bilirubin hepatic jaundice

Question 30

post hepatic jaundice

Answer 30

often due to biliary obstruction: gallstones/tumors | labs: increase total bili & increased unconjugated bili

Question 31

cirrhosis

Answer 31

scarring of liver tissues so that blood flow & liver function are blocked

Question 32

causes of cirrhosis

Answer 32

``` alocholism, chronic hep C, other chronic hep autoimmune hep drugs toxins Wilson's disease hemochromatosis galactosemia ```

Question 33

Lab results for Reye's syndrome

Answer 33

increased total bili, 3x increase in ammonia 3x increase in AST & ALT

Question 34

Enzyme used to detoxify alcohol

Answer 34

alcohol dehydrogenase (ADH) & Acetaldehyde dehydrogenase

Question 35

lab results for alcoholic fatty liver

Answer 35

increased AST, ALT GGT

Question 36

lab results for alcoholic hepatitis

Answer 36

increased AST, ALT, GGT, Bilirubin, decreased albumin prolonged prothrombin time

Question 37

Drugs of concern for liver damage

Answer 37

acetaminophen (Tylenol), tranquilizers, some antibiotics, anti-neoplastic drugs, lipid lowering meds, anti-inflammatory drugs

Question 38

liver function labs

Answer 38

``` bilirubin AST, ALT, ALP, GGT, LD >3 ALP is extrahepatic Albumin, alpha-globulins, gamma globulins, coag proteins, IgG & IgM ammonia levels hepatitis antigens & antibodies ```

Question 39

AST & ALT

Answer 39

increase a lot in liver disease, use serial measurements | less increase in liver obstruction

Question 40

ALP

Answer 40

located in bile canaliculi | intrahepatic <3x separate increases from bone ALP

Question 41

5'NT

Answer 41

increase in liver not bone