Physiology and pharmacology of the liver

Question 1

What is the metabolic hub of the body?

Answer 1

The Liver

Question 2

What metabolism does the liver regulate?

Answer 2

Carbohydrate
Lipid
Amino Acid

Question 3

What are the 4 steps of carbohydrate metabolism?

Answer 3

Glucogenesis
Glycolysis
Glycogenesis
Glycogenolysis

Question 4

What are the steps for fat metabolism?

Answer 4

Processing of chylomicron remnants
Synthesis of lipoproteins and cholesterol
Ketogenesis

Question 5

What are the steps of protein metabolism?

Answer 5

Synthesis of plasma proteins
Transamination and deamination of amino acid
conversion of ammonia to urea

Question 6

Many important hormones are de/activated by the liver True/false?

Answer 6

True

Question 7

What is deactivated by the liver?

Answer 7

Insulin
Glucagon
Anti-diuretic hormone (ADH)
Steroid hormone

Question 8

What is activated by the liver?

Answer 8

Conversion of thyroid hormone to triiodothyronine

Conversion of vitamin D to 25-hydroxyvitamin D2

Question 9

What does the liver store?

Answer 9

Fat soluble vitamins (ADEK)
Water soluble vitamin B12
Iron
Copper
Glycogen

Question 10

Where is vitamin A stored?

Answer 10

In ito cells

Question 11

Where is vitamin K stored?

Answer 11

Hepatocytes

Question 12

What proteins does the liver synthesize?

Answer 12

Coagulation factors 2,7,9 and 10
Proteins C+S
Albumin
Complement proteins
Apolipoproteins
Carrier proteins - a protein which combine to other molecules and carry them round the body

Question 13

What are factors that protect the liver?

Answer 13

Kupffer cells

Production of immune factors: Acute phase proteins

Question 14

What are Kupffer cells and what is their role?

Answer 14

Liver Phagocytes

Digest and destroy cellular debris and invading bacteria

Question 15

What is the liver involved in the detoxification of?

Answer 15

Endogenous (Bilirubin) and exogenous substances (Drugs/alcohol)

Question 16

What is the role of bile?

Answer 16

Participation in the digestion and absorption of fatzs and the exretion of products of metabolism

Question 17

How much bile is produced each day?

Answer 17

0.6-1.2L

Question 18

What are the two types of bile?

Answer 18

Hepatic (Hepatocytes)

Secretory (Cholangiocytes)

Question 19

Between meals where does bile reside?

Answer 19

Stored in the gall bladder due to the sphincter of oddi being closed

Question 20

What does the gallbladder do to bile?

Answer 20

Removes water

Can cause solids to precipitate out (cholesterol) leading to gall stones

Question 21

What happens to bile during a meal?

Answer 21

Chyme in duodenum stimulates gall bladder smooth muscle to contract (via CCK and Vagal impulses)
Sphincter of oddi opens (Via CCK)
Bile spurts into duodenum via cystic and common bile ducts

Question 22

What is gallbladder secretion high in?

Answer 22

Bicarbonate

Question 23

What does slightly alkaline bile assist in?

Answer 23

Protection of the gastric mucosa

Question 24

What does bile contain?

Answer 24

Secretion of hepatocytes
Secretion of bile ducts (cholangiocytes)
Bile acids (cholic and chenodeoxycholic)
Water and electrocytes
Lipids and phospholipids
Cholesterol
IgA
Bilirubiin

Question 25

What is bilirubin?

Answer 25

Breakdown product of porphyrin component of haemoglobin
Pigment rendering urine yellow and faeces brown
When present in excess causes jaundice

Question 26

What is the process of bile secretion through the duodenum?

Answer 26

The hepatocytes produce two primary bile acids, these appear in the bile, during feeding they enter the duodenum with the rest of the bile, as it moves along the intestine, bacteria is encountered, bacteria then attacks the primary bile acids and converts them to the secondary bile acids. Both secondary and primary acids are reabsorbed where they return to the liver through the portal system where the process can begin again

Question 27

What does the liver do when low in salt?

Answer 27

It uses Cholesterol

Question 28

What is the most common pathology of the biliary tract?

Answer 28

Cholelithiasis

Question 29

What is the best treatment for large, hard, calcified symptomatic gall stones?

Answer 29

Laparoscopic cholecystectomy

Question 30

What is the treatment for non-calcified gall stones?

Answer 30

Ursodeoxycholic acid

Question 31

When may potent analgesia be required?

Answer 31

Biliary colic

Question 32

What drug relieves biliary spasm?

Answer 32

Atropine

GTN

Question 33

What percentage of the bile salts that enter the duodenum are lost in faeces?

Answer 33

5%

Question 34

What occurs to the majority of the bile?

Answer 34

Most is reabsorbed by active transport in the terminal ileum and undergoes enterohepatic recycling

Question 35

What are three bile acid sequestrants (resins)?

Answer 35

Colvesam
Colestipol
Colestyramine

Question 36

Are the bile acid sequestrants (resins) absorbed or digested?

Answer 36

Neither, they bind to bile acids to prevent their reabsorption

Question 37

What do the resins do?

Answer 37

Lower plasma LDL cholesterol indirectly
Treating hyperlipidemia and cholestatic jaundice
Bile acid diarrhoea

Question 38

What are the disadvantages of resins?

Answer 38

Unpalatable and inconvinient
GI side effects - frequently cause diarrhoea
Deficiency of fat soluble vitamins

Question 39

What occurs in phase I of drug metabolism in the liver?

Answer 39

Oxidation (Mediated by cytochrome P450’s)
Reduction
Hydrolysis

Adds a polar group to the compound to causes one of these reactions to occur

Question 40

What does it mean when a drug is Lipiphyllic?

Answer 40

Difficult for the kidney to excrete

Stay in the body for a long time

Question 41

What is phase 2 of drug metabolism in the liver?

Answer 41

Conjugation
Adds an endogenous compound increasing the polarity of a drug with glucaronyl, sulphate, methyl, acetyl, glycyl etc. Makes them more readily excretable for the body