GI 10 and 11: Liver and bile

Question 1

Wht are the 3 main functions of the liver

Answer 1

metabolism, detoxification, excretion

Question 2

What is the portal circulation?

Answer 2

Blood from GI organs goes to portal vein instead of straight to vena cava –> allows liver to have a first “look over” of blood from GI tract (detox!!)

Question 3

Hepatocyte

Answer 3

liver cell

Question 4

Organizing structure hepatocytes are in

Answer 4

plates

Question 5

what kinds of vessels supply hepatocytes

Answer 5

sinusoids (low resistance cavities that are supplied by portal vein and hepatic artery)

Question 6

Hepatic triad

Answer 6

Branches of hepatic artery, portal vein and bile duct

Question 7

Zone 1

Answer 7

Periportal cells - cells closest to triad, very sensitive to oxidative injury and hve largest O2 and nutrient supply. These are most active in detoxiication

Question 8

Zone 2

Answer 8

intermediate zone between zones 1 and 3

Question 9

Zone 3

Answer 9

Pericentral cells - closest to hepatic vein, mmost sensitive to ischemia and very active in bile synthesis

Question 10

where does biliary system start?

Answer 10

Hepatocytes

Question 11

Canaliculi in liver connect what?

Answer 11

apical membranes of adjacent hepatocytes

Question 12

Cholangiocytes

Answer 12

Canaliculi drain bile from liver and transport to biliary ductules - these ductules are lined by cholangiocytes which are a kind of columnar epithelial cell

Question 13

Zones 1-3 in level of oxygenation

Answer 13

Zone 1 > zone 2 > zone 3

Question 14

Biliary ductules drain into what

Answer 14

bile ducts - which coalesse into right and left hepatic ducts, and then into hepatic duct and go to either gall bladder (via cystic duct) or small intestine via common bile duct

Question 15

What metabolism do hepatocytes play a role in

Answer 15

carbohydrates
lipids
proteins

Question 16

what do heptocytes do for carb metabolism

Answer 16

gluconeogenesis
glycogenolysis

Impaired liver fxn results in hyperglycemia during and after meals, and hypoglycemia between meals

Question 17

Hepatocyte fxn in lipid metabolism

Answer 17

Rich store of enzymes for FA oxidation - contributes to generating energy
convert carbs to lipids - synthesis of lipoproteins, cholesterol, phospholipids (metabolism classes will cover this gain)
Convert cholesterol to bile acids

Question 18

Role ofl liver in protein metabolism

Answer 18

synthesize non-essential AA’s nd modifies these so they can go into biosynthetic pathways for carb synthesis
synthesizes plasma proteins (including albumin)
converts ammonia to urea

Question 19

How does liver protect body from toxins

Answer 19

Senses endogenous or exogenous toxic molecules (so anything cells produce and are in blood, but also any drugs or bacterial toxins), done in 2 phases

Question 20

phase 1 of liver detoxification

Answer 20

oxidation, hydroxylation - catalyzed by cytochrome p450 enzymes

Question 21

phase 2 of liver detoxification

Answer 21

cnjugate substances with glucuronide sulfate, AA’s, or GSH to make the m water soluble, then excrete products in feces via bile or in urine via kidney

Question 22

Wht role does liver play in excretion?

Answer 22

Large water soluble catabolites and molecules can be excreted via bile –> go to feces

Question 23

Constituents of bile

Answer 23

bile salts
phospholipids
proteins
cholesterol
bile pigments (bilirubin) 
electrolytes (isotonic to plasma)

Question 24

2 primary bile acids synthesized by hepatocytes

Answer 24

cholic acid and chenodeoxycholic acid

Question 25

Secondary bile acids and how are they synthesized

Answer 25

Colonic bacterial enzymes act on primary bile acids to form secondray ones, whch are ursodeoxycholic acid, deoxycholic acid, and lithocholic acid)

Question 26

how are bile salts made / how are bile acids made more soluble

Answer 26

in hepatocytes, primary and secondary bile cids are conugated with glycine nd taurine with exception of lithocholic cid which is sulfated instead

Question 27

Conjugated bile acids are absorbed __ by ____ | Deconjugated bile acids are absorbed ___ by ____

Answer 27

in ileum by ASBT | In colon by passive diffusion

Question 28

How are bile acids brought back to liver

Answer 28

entoerhepatic circulation

Question 29

If you have an ileal resection what happens to bile circulation

Answer 29

you lose a shit ton of bile recycling

Question 30

What can cholangiocytes do to bile

Answer 30

modify it - Glucose, AAs are reclaimed by transporters, and chloride is exchanged for HCO3- so bile is slightly alkaline

Question 31

where is bile stored

Answer 31

gallbladder

Question 32

in between meals, outflow of bile is blocked by what

Answer 32

constriction of sphincter of oddi

Question 33

How does bile concentrate

Answer 33

unknown mechanism but Na/H exchanger plays a role, sodium is absorbed which will bring water with

Question 34

What hormone is the main player in getting bile to be secreted from GB into duodenum

Answer 34

CCK Ach can also be dumped on GB to get it to squeeze from neural reflexes

Question 35

What are gallstones

Answer 35

precipitated bile constituents

Question 36

What comprises gallstones

Answer 36

cholesterol or calciu-biliruinate pigment stores

Question 37

What usually prohibits gallstone generating

Answer 37

anti nucleating proteins

Question 38

If you skip breakfast what might happen

Answer 38

gallstones

Question 39

What is bilirubin a consequence of

Answer 39

heme degeneration

Question 40

What does bilirubin bind to in blood

Answer 40

albumin

Question 41

what takes bilirubin into hepatocytes

Answer 41

organic anion transporting polypeptide transporter (OATP)

Question 42

in microsomes of hepatocytes, bilirubin is conjugated to what via what enzyme

Answer 42

Glucoronic acid by UDP glucuronyl transferase

Question 43

Why do some newborns develop jaundice

Answer 43

UDP glucunoryl transferase is not synthesized quickly after birth

Question 44

Conjugated bilirubin is water soluble or insoluble

Answer 44

soluble and part of it is xcreted in urine (remainder is secreted in bile nd travels to small intestine to do so)

Question 45

In terminal ileum, what happens to biliruben

Answer 45

deconjugated by bacterial enzymes and metabolized to urobilinogen

Question 46

Can bilirubin cross BBB?

Answer 46

yes and it can cause neurological damage and be fatal if it isn't yeeted

Question 47

Increase in unconjugated bilirubin would be a reflection of what

Answer 47

loss/absence of UGT sudden oversupply of heme liver failure

Question 48

High conjugated bilirubinemia would be do to

Answer 48

defect in OATP , blockage of bile flow

Question 49

Jaundice

Answer 49

yellow color of skin and conjunctiva due to accumulation of bilirubin due to hemolysis, hepatic dysfunction, or gallbladder duct issues

Question 50

What is a product of protein catabolism the liver must deal with to safely excrete

Answer 50

ammonia - turns to urea via urea cycle

Question 51

What are the 2 main generators of ammonia for us

Answer 51

protein catabolism and colonic bacteria

Question 52

Is urea ammonia membrane permeable

Answer 52

yes

Question 53

What happens to ammonium and urea

Answer 53

excreted in stool and urine

Question 54

Hepatic encephalopathy

Answer 54

Chronic liver disease --> declining mental fxn, caused by detox function being fucked --> this is fatal

Question 55

Liver cirrhosis

Answer 55

irreversible scarration and destrution of liver, caused by injury, fibrosis, and tissue degeneration from dugs, poisons, and hepatitis

Question 56

Portal hypertension

Answer 56

Increased BP in sinusoids reflects to portal vein --> results in splenomegaly , ascites, and other complications caused by increased vscular resistance in lier