Hepatobiliary 1

Question 1

Where is the liver located and what surrounds it?

Answer 1

Upper right abdominal quadrant; tough fibroelastic capsule

Question 2

Functional unit of the liver is the:

Answer 2

lobule (all hepatocytes that drain into single central branch of the hepatic vein)

Question 3

What is at the center of each lobule? The corner?

Answer 3

Center = Hepatic vein

Corner = Triad (bile duct, hepatic artery, portal vein)

Question 4

Hepatocytes form an epithelium that separates 2 fluid spaces; one is for __________ and the other one called the ___________ which receives blood from what structures?

Answer 4

bile

sinusoid; hepatic artery and portal vein

Question 5

What do microvilli on BOTH sides of hepatocytes do?

Answer 5

Increase SA

Question 6

Where are Kuppfer cells found and what do they do?

Answer 6

found in sinusoid, macrophages that consume RBC’s, bacteria, etc.

Question 7

Where are the endothelial cells found and what do they do?

Answer 7

found in sinusoid; form porous structure that allows plasma and solutes to move through freely

Question 8

Where are stellate cells found and what do they do?

Answer 8

in the perisinusoidal space; fat-storing cells involved in storage of vitamin A.

They can transform into myofibroblasts and help regenerate liver

Question 9

Function of hepatocytes differ, it all depends on:

Answer 9

Oxygen supply

Question 10

Which hepatocytes are highly oxygenated and involved in amino acid metabolism, gluconeogenesis, ureagenesis, cholesterol synthesis, and bile formation?

Answer 10

Cells in Zone I (farthest from central vein)

Question 11

Which hepatocytes get the least amount of oxygen and are involved in glycolysis, glycogen synthesis, lipogenesis, ketogenesis, and drug metabolism?

Answer 11

Cells in Zone III (closest to central vein)

Question 12

The valveless hepatic portal vein drains the stomach, splee, pancreas, and small/large intestine and supplies the liver with how much of its OWN oxygen need?

Answer 12

60-70% (even though venous!) with fast flow

Question 13

What does the hepatic vein do?

Answer 13

Carries venous outflow from liver to inferior vena cava

Question 14

Liver can do biotransformation via phase I and phase II reactions? What is biotransformation and what are the phases?

Answer 14

Biotransformation is: substances taken from blood are either returned to circulation or excreted in bile

Phase 1: oxidation-reduction using CYP450

Phase 2: makes metabolites more polar/water soluble in blood or bile for excretion

Question 15

What are the four major functions of the liver?

Answer 15

1. ) biotransformation
2. ) filtration
3. ) hormone conversion and activation
4. ) nutrient metabolism

Question 16

What cells perform filtration within the kidney?

Answer 16

Kuppfer cells

Question 17

What two hormones does the liver deal with?

Answer 17

• hydroxylation of vitamin D (initial site)

- deiondination of T4 into T3

Question 18

Carb metabolism:

Answer 18

1. ) Liver stores glucose as glycogen which it can breakdown to maintain blood sugar (7-20% weight)
2. ) during fasting the liver can use gluconeogenesis to synthesize glucose from AA and lactic acid
3. ) converts carbs into triglycerides for storage in adipose

Question 19

Lipid metabolism:

Answer 19

1.) fat is split into glycerol and fatty acids

Question 20

Almost all synthesis of fats from carbs and protein occurs in the liver. This fat can be transported as triglycerides in lipoproteins to be stored in:

Answer 20

Adipose tissue

Question 21

What does fatty acids oxidize into and what happens to it?

Answer 21

Acetyl-CoA;

• can enter krebs cycle to generate ATP
• synthesize cholesterol
• converted to keynotes during glucose deficiency

Question 22

Dietary cholesterol is packaged into _________ which can travel to adipose tissue or muscle

Answer 22

chylomicrons

Question 23

The liver can synthesize cholesterol “de novo”, this means:

Answer 23

Does not need a direct precursor to synthesize

Question 24

Liver takes up cholesterol in the form of LDL and can export it in 2 forms to:

Answer 24

• Synthesize bile acids directly
• Enter the blood in the form of VLDL to be transported to other cells for manufacture of cellular components (steroid hormones)

Question 25

Protein metabolism produces circulating plasma proteins like albumin, which:

Answer 25

Maintains plasma oncotic pressure and binds/transports substances in blood like hormones, drugs, etc.

Question 26

Transamination:

Answer 26

Transfer of AA group to an acceptor (ketoacid), which allows the AA to participate in gluconeogenesis or lipid synthesis

Question 27

Deamination:

Answer 27

conversion of AA to ketoacids and ammonia

Question 28

Ammonia is a byproduct of deamination, what does it convert to and what happens?

Answer 28

Urea, excreted by the kidneys or some diffused into intestines

Question 29

Some of the ammonia that enters the intestines (either from unabsorbed protein or bacterial deamination) is absorbed into portal circulation then converted to urea in liver. What happens with severe liver disease?

Answer 29

Urea synthesis is impaired and ammonia can accumulate into blood

Question 30

What is bilirubin?

Answer 30

A pigment that gives bile its color, product of RBC breakdown

Question 31

List the steps of how hemoglobin becomes conjugated bilirubin:

Answer 31

1. ) hemoglobin is broken down into biliverdin
2. ) this rapidly converts to free bilirubin which binds to albumin in the blood (still “free”)
3. ) When it gets to the liver, it is converted into conjugated bilirubin and glucuronic acid is added to it
4. ) exported into bile where it is now soluble!

Question 32

Bilirubin can be converted into uribilinogen by intestinal flora. What can urobilinogen do?

Answer 32

1. ) excreted in feces

2. ) return to liver via portal circulation to be re-excreted into bile (small amount to kidneys)

Question 33

Free bilirubin is also called (direct/indirect)

Answer 33

indirect

Question 34

Conjugated bilirubin is also called (direct/indirect)

Answer 34

direct

Question 35

What causes jaundice?

Answer 35

Elevated plasma bilirubin conc. (>1.5-3mg/dl)

• excessive RBC lysis
• decreased hepatic flow
• limited conjugation of bilirubin
• obstruction of canaliculi or bile ducts

Question 36

What does bile allow that the kidney cannot do?

Answer 36

Excretion of bilirubin, cholesterol, and other substances not excreted by the kidneys

Question 37

What is bile made up of?

Answer 37

Bile salts, bile acids, bilirubin, cholesterol, and lecithin

Question 38

Bile acids and bile salts promote digestion and absorption of lipids from intestines, how do they do this?

Answer 38

Aid in formation of micelles which emulsify lipids to be absorbed

Question 39

Which are neutral and not very water soluble: (bile acids or bile salts)?

Answer 39

Bile acids (they are de-protonated from bile salts in the duodenum and absorbed PASSIVELY)

Question 40

Which is more concentrated: (hepatic bile/gallbladder bile)?

Answer 40

Gallbladder bile (water is removed)

Question 41

Many bile acids are reabsorbed in the GI tract and brought where?

Answer 41

the liver (can recirculate 5 times during meal)

Question 42

The ALT and AST are liver function tests that increase in proportion with:

Answer 42

Breakdown of hepatocytes (liver damage)

Question 43

Serum albumin (PTT) tells us the livers ability to:

Answer 43

make necessary proteins (limits of blood flow?)

Question 44

Alkaline phosphatase measures:

Answer 44

hepatic excretory function