1. Anatomy & physiology of
gall bladder and biliary tree
Dr.Prashanth.S
1stYear PG
Dept.of General Surgery
2. Introduction
• Component of extrahepatic biliary system
along with
• Rt. and Lt.hepatic ducts
• Common hepatic duct
• Cystic duct
• Common bile duct
3. Embryology
• Liver primordium begins to form in third week
of IUL from caudal end of foregut.
• It elongates cranially and gives a small bud
on right side-”pars cystica” and the main part
gives rise to “pars hepatica”.
• From pars cystica gall bladder and cystic duct
are formed.
• Initially extra hepatic biliary apparatus is
occluded with endodermal cells which gets
canalized in later period.
4. Gall bladder
• Pear shaped
• 7-10cm long,
3cm broad.
• 30-50 ml
capacity.
• When
Obstructed
300ml.
7. Cystic duct
• 3-4 cm long
• Runs downwards,backwards and to the
left
• Ends by joining CHD at an acute angle to
become CBD.
• Mucous membrane of the cystic duct
forms a series of crescentic folds arranged
spirally-spiral valve of Heister.
10. Biliary tree
• Right and left hepatic ducts
• Common hepatic duct-3 cm, runs
downwards and is joined by cystic duct to
form common bile duct.
• Accessory hepatic ducts present in about
5% of subjects.
• Usually come from right lobe of liver.and
terminate either in gall bladder or CHD.
13. Common bile duct
• 7-11 cm long,6-8mm in diameter.
• 4 parts- Supraduodenal, Retroduodenal,
infraduodenal and intraduodenal.
• Within the wall of duodenum
hepatopancreatic ampulla/ampulla of vater
is formed by union of two ducts.
• Distal constricted end of ampulla opens at
the summit of major duodenal papilla (8-
10cm distal to pylorus.)
17. Blood supply
• Cystic artery-gall bladder,cystic
duct,hepatic ducts,and upper part of bile
duct.
• Posterior superior pancreaticoduodenal
artery-lower part of bile duct.
• Right hepatic artery –minor source of
middle part of bile duct.
20. Venous drainage
• Superior surface of GB drains into hepatic
veins.
• Rest of GB is drained by one or two cystic
veins which enter into right branch of
portal vein.
• Lower part of bile duct drains into portal
vein.
21. Lymphatic drainage
• Cystic lymph node of Lund and node of
anterior border of epiploic foramen
• Upper pancreaticosplenic nodes.
22. Nerve supply
• Cystic plexus of nerves
• Right and left vagus nerves
• Right phrenic nerve
• Pain from GB may be referred to stomach,
inferior angle of right scapula, right
shoulder.
29. • Normal adult 500-1000ml/day.
• Secretion of bile is responsive to
neurogenic,hormonal,chemical stimuli.
• Stimulators:
Hcl
Partially digested proteins, fatty acids(via;
secretin)
Vagus stimulation
• Inhibitors:
• Splanchnic nerve stimulation
30. Bile composition
• Bile is mainly composed of water,
electrolytes, bile salts, proteins, lipids, and
bile pigments. Sodium, potassium, calcium,
and chlorine have the same concentration in
bile as in plasma or extracellular fluid.
• pH of bile is neutral/slightly alkaline and it
varies with diet.(proteins shifts it towards
acidic).
• Ratio of bile acids: phosphatidyl choline:
cholesterol is approx;10:3:1.
32. • Almost 95% of bile acid is reabsorbed and
returned to liver via portal circulation-
Enterohepatic circulation.
• Remaining 5% is excreted through stool and
urine.
• FUNCTION: concentrate, store and regulate
the flow of bile in response to meal.
• Function of bile is digestion and absorption of
fats. Also it is the major excretory route for
lipid soluble waste products.
33.
34. Absorption and Secretion
• In fasting state 80% of the bile secreted by the
liver is stored in the gall bladder.
• It rapidly absorbs sodium, chloride, and water,
concentrating the bile as much as 10-fold.
• The epithelial cells of the gallbladder secrete two
important products into the gallbladder lumen:
glycoproteins and hydrogen ions.
• The acidification promotes calcium solubility,
thereby preventing its precipitation as calcium
salts
35. Motor activity
• During fasting the gallbladder repeatedly empties
small volumes of bile into the duodenum which is
mediated by motilin.
• In response to a meal, the gallbladder empties by
a coordinated motor response of gallbladder
contraction and sphincter of Oddi relaxation.
• One of the main stimuli to gallbladder emptying is
the hormone cholecystokinin.
• When stimulated by eating, the gallbladder
empties 50 to 70% of its contents within 30 to 40
minutes. Over the following 60 to 90 minutes, the
gallbladder gradually refills.
36. Neurohormonal regulation
• The vagus nerve stimulates contraction of the
gallbladder, and splanchnic sympathetic
stimulation is inhibitory to its motor activity.
• Antral distention of the stomach causes both
gallbladder contraction and relaxation of the
sphincter of Oddi.
• Hormonal receptors are located on the smooth
muscles, vessels, nerves, and epithelium of the
gallbladder.
• CCK is released into the bloodstream by acid, fat,
and amino acids in the duodenum.
• CCK has a plasma half-life of 2 to 3 minutes and is
metabolized by both the liver and the kidneys.
37. Contd…
• CCK acts directly on
smooth muscle receptors
of the gallbladder and
stimulates gallbladder
contraction.
• CCK stimulation of the
gallbladder and the biliary
tree also is mediated by
cholinergic vagal neurons.
• In patients who have had a vagotomy, the
response to CCK stimulation is diminished and the
size and the volume of the gallbladder are
increased.
38. Sphincter of oddi
• It is a complex structure that is functionally
independent from the duodenal musculature and
creates a high-pressure zone between the bile
duct and the duodenum.
• The sphincter of Oddi is about 4 to 6 mm in length
and has a basal resting pressure of about 13
mmHg above the duodenal pressure.
• On manometry, the sphincter shows phasic
contractions with a frequency of about four per
minute and an amplitude of 12 to 140 mmHg.
• The spontaneous motility of the sphincter of Oddi
is regulated by the interstitial cells of Cajal through
intrinsic and extrinsic inputs from hormones and
neurons acting on the smooth muscle cells.
39. Contd..
• Relaxation occurs with a rise in CCK,
leading to diminished amplitude of phasic
contractions and reduced basal pressure,
allowing increased flow of bile into the
duodenum.
