Final Exam GI Physiology: Liver

Question 1

Most of the hepatic blood supply is ____________ and delivered by the hepatic portal vein.

Answer 1

hypoxygenated

Question 2

The hepatic artery delivers ________ blood to the liver.

Answer 2

oxygenated

Question 3

How does the liver metabolize carbohydrates?

Answer 3

Uses carbs for glycogenesis, glycogenolysis, and GLUconeogenesis

Question 4

How does the liver metabolize lipids?

Answer 4

Beta-oxidation of fatty acids
FA and TAG synthesis
Synthesis and export of: ketones, cholesterol, and lipoproteins

Converts carbs and AAs into triacylglycerol

Question 5

How does the liver metabolize proteins?

Answer 5

Deamination and transamination

Plasma protein synthesis of:
Albumin, a & B globulins, coagulation factors, complement proteins, plasma antiproteases

NH3 uptake, urea and glutamine synthesis

Question 6

What does the liver do with vitamins?

Answer 6

Stores them! A, D, and B12

Question 7

What does the liver do with iron?

Answer 7

Stores it!

Question 8

What is a Phase I Transformation reaction?

Answer 8

A biotransformation that provides polar groups for reactions.

Question 9

What is a Phase II Transformation reaction?

Answer 9

A reaction that conjugates the products of Phase I reactions to produce a strong acid.

Question 10

What do Phase I reactions do to the toxicity of a compound?

Answer 10

Increases OR decreases the toxicity

Question 11

Bile is produced by which organ?

Answer 11

The liver

Question 12

What are the 4 functions of bile?

Answer 12

1. Emulsification of lipids
2. Excretion of wastes (bilirubin, drugs, hormones)
3. Protection (IgA)
4. Protection (bile acids kill bacteria)

Question 13

What are the 6 components of bile?

Answer 13

1. Electrolytes (with water)
2. Phospholipids (mostly lecithans)
3. Cholesterol
4. Bile acids
5. IgA
6. Biotransformation waste products

Question 14

How does the liver make primary bile acids?

Answer 14

It conjugates cholesterol and amino acids to make bile acids

Question 15

Where are primary bile acids converted into secondary bile acids?

Answer 15

In the small intestine

Question 16

What does high plasma [bile acids] indicate?

Answer 16

Liver disease, compromised bile flow, accumulation of bile, and backflux of bile into circulation

Question 17

Where are bile acids reabsorbed?

Answer 17

Ileum (99% absorbed here)

Question 18

How do bile acids get to the liver?

Answer 18

Through the portal vein

Question 19

Describe the route of bile acids

Answer 19

Liver–> Bile duct –> Intestine –> Portal vein –> Liver

Question 20

What is enterohepatic circulation?

Answer 20

The route that bile acids take starting and ending at the liver

Question 21

What cells are majorly responsible for the degradation of red blood cells and where are they found?

Answer 21

Macrophages found in the spleen degrade RBCs

Question 22

After an RBC is degraded, what happens to the hemoglobin?

Answer 22

It is reduced to biliverdin and reduced further by macrophages, then released as unconjugated bilirubin

Question 23

Is unconjugated bilirubin toxic?

Answer 23

YES!

Question 24

Can unconjugated bilirubin diffuse through cell membranes?

Answer 24

YES!

Question 25

What plasma protein has a high affinity for unconjugated bilirubin?

Answer 25

Albumin

Question 26

Why is it advantageous that albumin has a high affinity for unconjugated bilirubin?

Answer 26

Because unconjugated bilirubin is toxic and can pass through cell membranes. When albumin binds to it, a complex is formed. This complex CANNOT pass through cell membranes.

Question 27

Hepatocytes have albumin receptors which allows for rapid uptake of _________ ________.

Answer 27

unconjugated bilirubin

Question 28

How does unconjugated bilirubin become conjugated bilirubin?

Answer 28

It is acted on by glucuronyl transferase (a conjugating enzyme that performs a Phase II rxn). This produces conjugated bilirubin.

Question 29

Is conjugated bilirubin able to diffuse across cell membranes?

Answer 29

NO, it's water soluble and not bound by albumin

Question 30

Conjugated bilirubin is also known as ________ bilirubin.

Answer 30

DIRECT

Question 31

Unconjugated bilirubin is also known as _____ bilirubin.

Answer 31

INdirect

Question 32

Both forms of bilirubin are colorful _________.

Answer 32

pigments

Question 33

What happens when plasma [bilirubin] rises?

Answer 33

A yellow color is imparted and Jaundice or Icterus occurs

Question 34

What substance is secreted into the bile canaliculi and becomes a component of bile?

Answer 34

Conjugated bilirubin

Question 35

How does conjugated bilirubin get into the small intestine?

Answer 35

Through the bile duct

Question 36

What happend to conjugated bilirubin when it is in the lumen of the small intestine?

Answer 36

Acted on by bacteria that cleave off the glucuronide residue to make free bilirubin.

Question 37

What is free bilirubin reduced to?

Answer 37

Urobilinogen and Stercobilinogen (these terms refer to the ultimate route of excretion- urinary or fecal)

Question 38

How does yellow bile pigment end up in the urine?

Answer 38

Intestinal bacteria removes the gluconuride conjugate residue making the molecule MORE lipid soluble. This allows urobilinogen to be absorbed by the terminal ileum and large intestine. During transfer to the liver via the hepatic portal vein, some urobilinogen escapes and is excreted by the urinary route.

Question 39

How do bile acids enter the bile canuliculi?

Answer 39

By using membrane pumps that use ATP

Question 40

The presence of bile acids in the canuliculi draws water by __________ and electrolytes by _________.

Answer 40

Osmosis; solvent drag

Question 41

What are cholangiocytes?

Answer 41

bile ductular cells

Question 42

How are bile ductular cells like pancreatic ductular cells? What is the result?

Answer 42

They both exchange HCO3- for Cl- which increases the pH of bile (makes it more basic)

Question 43

What stimulates bile and pancreatic ductular cells?

Answer 43

Secretin

Question 44

What are choleliths?

Answer 44

Gall stones