Bile physiology & Pathophysiology of Gallstones.pdf

Bile physiology & Pathophysiology of Gallstones.pdf

1. Bile physiology &
Pathophysiology of Gallstones
XENIA C. PLAZA, MD
Level 1 General Surgery Resident

2. BILE FORMATION

3. 2 primary roles of bile
●Excretion of organic compounds
●Intestinal absorption of lipids

4. BILE COMPOSITION
●WATER
○85%
●ORGANIC SOLUTES
○Bilirubin
■Hemoglobin → Bilirubin → conjugated wtih glucuronic acid → excreted into
canaliculus
○Bile salts
■primary bile salts (cholic and chenodeoxychcolic) → conugated with taurine and
glycine → bacterial alteration in the intestine → secondary bile salts (deoxycholate
and lithocholate)
■PURPOSE: solubilize lipids and facilitate absorption
○Phospholipids
■lecithin (95%)
○Cholesterol

5. BILE FLOW
●daily secretion of 750-1000ml per day
●INCREASED BILE SECRETION
○Vagal stimulation
○GI hormones: secretin, cholecystokinin, gastrin and glucagon
●DECREASED BILE SECRETION
○Splanchnic stimulation
●MOST IMPORTANT FACTOR IN REGULATING BILE FLOW: Rate of bile salt
synthesis by hepatocytes

6. BILE SALT SECRETION
●formed at a rate of 500 to 600 mg per day
●2 pathways for bile acid synthesis
○Classic - cholic cacid (60-70%)
○Alternative - chenodeoxycholic acid

7. BILIRUBIN SECRETION
●Source
○Heme 80-85%
○Hepatic hemoproteins
15-20%

8. Entero-hepatic circulation
●cycling of bile acids between
the liver and intestine
●highly efficient - 95% are
reabsorbed

9. PATHOPHYSIOLOGY OF GALLSTONES

13. THANK YOU!