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Facts about bile
• Bile is produced in the liver
• Bile is stored in the gallbladder.
• Bile is secreted into the small
intestine.
• Bile salts are absorbed in the small
intestine and recycled.
Biliary tract
Biliary tract has 4 components
Function of CCK on biliary secretion
Neurohormonal control of gallbladder contraction and biliary
secretion
Liver
**Largest organ in the body
**High blood flow - 1350 ml/min to liver sinusoids (1050 ml from the portal vein,
300 ml from hepatic artery)
Physiologically – low vascular resistance (small difference between pressures in
the portal vein and hepatic vein). 9 mm Hg in portal vein and about zero!! in
hepatic vein
Functions of the amazing liver
1. Formation and secretion of bile
2. Excretion of bilirubin
3. Detoxication of various substances
• Metabolic products of intestine microbes:
• Exogenous toxins (drugs, alcohol, poisons)
• Hormones (thyroxine, estrogen, cortisol, aldosterone)
4. Synthesis of plasma proteins:
1. Albumin
2. Clotting factors (synthesis of most of the coagulating factors)
3. Hormone-binding proteins
Functions of the liver (cont.)
5. Blood reservoir – filtration and storage of blood (450 ml =
almost 10 % of the body’s total blood volume). This increases in cardiac
failure.
6. Immunity (Kupffer cells = macrophages). Kupffer cells remove
aged RBCs, bacteria, viruses, antigen-antibody complexes and endotoxin.
They produce inflammatory mediators for local and systemic use.
Functions of the liver (cont.)
7. Vitamins - metabolism and storage of vitamins A, D
and B12
8. Relation to blood formation
• storage of vitamin B12
• metabolism of iron and its storage as ferritin (hepatic
cell contains apoferritin and when excess of iron in the
blood it forms ferritin) = blood iron buffer
• participation (to small extent) on production of
erythropoietin
Liver and protein metabolism
***Deamination of amino acids
***Formation of urea for removal of ammonia from the
body fluids
*** Formation of plasma proteins (90% of all plasma
proteins, up to 50 g of plasma proteins daily) –gamma
globulins are not formed by liver.
***Interconversions of the various amino acids and
synthesis of other compound from amino acids
Liver and carbohydrate metabolism
***Maintaining a normal blood glucose concentration
***Storage of glycogen – removing excess of
glucose from blood, storage, fast return when the blood
concentration decreases = Glucose buffer function
***Conversion of galactose and fructose to glucose
***Gluconeogenesis
***Formation of many chemical compounds from
intermediate products of carbohydrate metabolism
Liver and fat metabolism
***Oxidation of fatty acids to supply energy for other body
function
***Synthesis of large quantities of cholesterol (80% of
cholesterol synthesized in the liver is converted
into bile salts), phospholipids, and most lipoproteins
***Inactivation of steroids and their excretion of the body
***Synthesis of fat from proteins and carbohydrates