Liver And Gsll Bladder Function

Question 1

Major constituents of bile

Answer 1

250-1500mls of bile per day 
Bile salts
Phospholipids (lectilnin)
Bile pigment (bilirubin)
Cholesterol 
Inorganic ions

Question 2

Bile salts

Answer 2

Derivatives of cholesterol
Important for lipid digestion and absorption
Enterohepatic recycling

Question 3

Enterohepatic recycling

Answer 3

Bile salts produced by liver, drain in to gall bladder
Enter small intestines via common bile duct
95% of bile salts reabsorbed into hepatic portal vein
5% lost in faeces
Bile salts returned to liver

Question 4

Excretion of bile pigments

Answer 4

Major breakdown product of Haemoglobin
Conjugated with glucuronic acid-> increases polarity and solubility
Transported to liver bound to plasma albumin
Bilirubin glucuranide is broken down by bacteria to form bilirubin
Combined with H2 to form urobilinogen
Recycled from intestine in portal system or excreted in systemic
Cholesterol is the major excretion site of bile
Inorganic ions accompany osmotic effect of bile acid secretion

Question 5

Role of the gall bladder in storing and secreting bile

Answer 5

Rate of production is dependent on hepatocyte secretions
Resting-> flow in to duodenum prevented by closer of sphincter of oddi-> in to gall bladder
Bile becomes concentrated due to reabsorption of salts and water in the gall bladder
Neural and CCK release stimulated by fat in duodenum-> relax sphincter of oddi, contracts gall bladder-> bile into duodenum

Question 6

Functions of the liver

Answer 6

Detoxification
Metabolism:
Plasma glucose/amino acid concentrations-> absorbed nutrients pass through portal circulation
Fructose and galactose to glucose
Glucose taken up by liver-> glycogen-> stored or triacylglycerol
Fats+protein-> lipoproteins released
Remainder of glucose is taken up by adipose
Synthesis of albumin and clotting factors
Storage of fat soluble vitamins, iron, copper

Question 7

Detoxification

Answer 7

Multiple enzyme systems allow modification of chemical structures
Generally aim to increase water solubility
Endogenous-> insulin, glucagon, aldosterone, female sex hormones
Exogenous-> drugs
Phase 1-> oxidation/reduction
Phase 2-> methylation, conjugation
Produce-> acetic acid, amino acid, sulphate, glucuronic acid

Question 8

Jaundice

Answer 8

Bilirubin accumulation in plasma
Greater than 59mM
Yellowing of skin, sclera and mucous membranes
Hernicterus-> deposits in the brain-> nerve degeneration
Treat with light

Question 9

Haemolytic jaundice

Answer 9

Excessive haemolysis of RBC’s-> overwhelms liver capacity

Question 10

Intra hepatic jaundice

Answer 10

defect in uptake or conjugation or secretion of bilirubin by hepatic cells

Question 11

Obstructive jaundice

Answer 11

Blockage of bile ducts

Question 12

Physiological jaundice

Answer 12

New borne

Poor bilirubin conjugating

Question 13

Hepatitis

Answer 13

Infection/inflammation of the liver
Acute-> viral, drugs
Chronic-> 6 months viral B and C

Question 14

Cirrhosis

Answer 14

Necrosis of the liver cells
Replaced by fibroblasts
Alcohol and hep B and C
Irreversible

Question 15

Liver functions

Answer 15

Bile production
Metabolism
Detoxification