Module 4 : The Biliary System Flashcards
The biliary tree path
lobules (bile canaliculi) - lobular bile ducts - right and left hepatic duct - common hepatic duct + cystic duct - common bile duct
bile canaliculi
- located between the hepatocytes
- intercommunicating network
- anastomose to form lobular bile ducts
- travel with portal vein and hepatic artery (portal triad)
right and left hepatic duct
- formed by union of multiple lobular bile ducts
- at level of porta hepatis right and left join to form common hepatic duct
common hepatic duct
- anterior to the portal vein
- anterior and lateral to right hepatic artery
- travels in free edge of lesser omentum
- 4 mm diameter
common bile duct
- length determined by insertion point
- anterior and lateral to main portal vein’
- 4mm through 40’s then add 1mm/10yrs
- 10mm normal with cholecystectomy
- ## TRAVELS THROUGH HEPATODUODENAL LIGAMENT
mickey mouse
CBD anterolateral HA anteromedial MPV posterior
4 segments of CBD
- 1st (supraduodenal)
- 2nd (retroduodenal)
- 3rd (infra duodenal)
- 4th (intraduodenal)
intraduodenal segment of CBD
- 4th part
- enters 2nd portion of duodenum and inserts into ampulla of Vater
- narrowest portion of extrahepatic biliary tree
+ where stones like to sit
sphincter of oddi
- regulates bile for into duodenum
cystic duct
- joins CHD 1-2cm above duodenum to form CBD
- arise from superior aspect of tech of GB
- s shaped
- 3mm diameter 4cm in length
- contain spiral valves of heister
spiral valves of heister
- not true valves
+ mucosal folds - prevent duct from over distending or collapsing
intrahepatic ducts
- within the liver
- no more than 2mm in diameter
- branching pattern
- portal veins are landmarks for them
- TOO MANY TUBES = INTRAHEPATIC DUCT DILATION
gallbladder location
- posterior inferior surface of right lobe of liver
- GALLBLADDER FOSSA
- posterior and caudal to distal end of MLF
- intraperitoneal
GB position
- variable with patient position
- neck of GB fixed
- body and fundus are mobile
- neck most dependent in supine fundus most dependent in LLD
landmarks for GB
- MAIN LOBAR FISSURE = most reliable
- rpv
- duodenum
- right kidney
size and shape of GB
- pear/tear drop shape
- 8-9cm in length and 2-5cm in diameter
divisions of GB
fundus, body, neck
fundus of GB
- widest portion
- MOST DEPENDENT IN LLD
body of GB
- middle portion
- aka corpus
neck of GB
- tapered portion
- fixed position
- MOST DEPENDENT IN SUPINE
gallbladder wall
- in FASTING STATE LESS THAN 3mm
- 4 layers
+ mucosa
+ muscular layer
+ subserous layer
+ serous layer
mucosa layer
- inner epithelial lining
- concentrates bladder
muscular layer
- muscle
sub serous layer
- connective tissue
serous
- outer layer = in contact with peritoneum
Rokitansky - Aschoff sinuses (RA sinuses)
- multiple folds along inner border of GB coated with epithelial cells
- not seen unless pathology
function of biliary ducts
- drain liver of bile and carry to GI system
function of GB
- reservoir for bile
+ stored until required to aid in digestion
+ holds 40-70ml
+ concentrates bile by secreting mucus and absorbing water
hormone control of bile secretion
- ingestion of fats and amino acids duodenum releases CCK (cholecystokinin)
Cholecystokinin (CCK)
- released by duodenum with ingestion of fats and amino acids
- stimulates GB to contract and sphincter of oddi to relax
GB contraction time
- contracts 30 minutes following a meal
bile
- yellowish green liquid produced and secreted by hepatocyte
- consists of water, cholesterol, bilirubin, inorganic salts, bile acid
- breaks down fat and absorb fatty acids
bile salts
- 1gram of bile salts/day in liver
- cholesterol is precursor of bile salts
+ supplied by diet or synthesized by liver
bilirubin
- end product of hemoglobin decomposition
- bile pigment
- conjugates in liver
jaundice/icterus
- yellowish tint seen in body tissue due to large quantities of bilirubin
blood supply to GB
- arterial blood supply from cystic artery
- venous drainage occurs via cystic vein drains directly into portal vein
GB variants
- junctional fold
- Hartmans pouch
- phyrgian cap
- septations
- excessively mobile
- ectopic
- low lying
- embedded in liver
junctional fold
- occurs at junction of BODY AND NECK
- similar look as septation
Hartmans pouch
- OUTPOUCHING in area of GB neck
phyrigian cap
- GB partially folded onto itself in region of FUNDUS
sonographic appearance of GB
- anechoic or nearly anechoic
- thin echogenic walls
- sagital pear shaped
- trans is circle
GB exam
- px in supine and decubitus to move stones
- size, shoe, wall thickness, and fluid
- liver as wind to minimize reverb
- LPO good for measure CBD
- measure duct INNER TO INNER
+ distal to HA
lab tests
- bilirubin
- alkaline phosphatase
- leukocytes
- HIDA scan
- ERCP
bilirubin
- indirect = increased values \+ hemolysis \+ RBC degradation \+ abnormal hepatocellural uptake - direct = increased values \+ extra hepatic obstruction \+ bile duct disease \+ intraheptaic disruption
alkaline phosphatase (alk phos)
- increased value in EXTRAHEPATIC BILIARY OBSTRUCTION
leukocytes
- MEASURES REACTION OF BODY TO INFECTION
-
HIDA scan
- nuke med test
- ASSES GB FUNCTION
ERCP
- like fluoroscopy
- asses for obstruction
