Gallbladder - Hogan Flashcards
Compare and contrast the three anatomical components of the gallbladder and their compositions.
Fundus - Rounded edge, contains mostly smooth muscle.
Corpus - Main storage area, contains mostly elastic tissue.
Neck - Funnel-shaped, deep in Hartmann’s Pouch.
What signals increase (or decrease) bile secretion from the liver?
How much is made per day? How much of that is stored in the gallbladder?
Vagal stimulation and secretin increase bile production, while splanchnic stimulation decreases it.
0.5-1L. The gallbladder stores less than 100mL under normal conditions of fasting. (bear in mind bile production increases in feeding, much of the 1L is on-demand)
As bile is concentrated in the liver, what happens to the relative concentrations of bile, sodium, chloride, and bicarbonate?
Bile increases
Sodium increases
Chloride decreases
Bicarbonate decreases
(no idea how these can be reconciled with a net absorption of water, sodium and chloride)
If the gallbladder communicates with the biliary tree and not the liver directly, how is the gallbladder filled?
When and how is the gallbladder emptied?
Tonic contractions of the sphincter of oddi create positive pressure that drive bile into the gallbladder.
In feeding, CCK causes fairly rapid (30-40min) emptying by contraction of the gallbladder. This is coordinated with opening of the sphincter of Oddi by CCK and MMCs.
Where are bile acids reabsorbed?
95% in the terminal ileum, 5% in the colon.
Describe the innervation of the gallbladder.
What is the functional significance of this?
Sympathetic innervation via the celiac plexus (T8, T9).
As this is a common site of pain referral, gallbladder tract pain cannot be easily isolated.
What is the most common gastrointestinal disorder in the US?
Gallstones.
Compare the composition and formation of cholesterol and pigmented stones.
Cholesterol: Formed from cholesterol hypersecretion or inadequate bile acids, phospholipids. Needs a nucleation site and usually low gallbladder motility.
Pigmented: Unconjugated bilirubin deposition.
Describe the epidemiology of gallstones–who gets them?
The four Fs: Fat, female, forty and fertile.
Caucasian and native american prevalences.
Why do gastric bypass patients usually have cholecystectomies?
Gallstones occur often in people with rapid weight loss. May as well get it while you’re in there…
What is biliary sludge, and when does it form?
Biliary sudge is a mixture of calcium bilirubinate and cholesterol crystals in the gallbladder which is prone to stone formation.
Seen in chronic cirrhotic diseases, hemolysis, crohn’s…and with drugs like ceftriaxone/octreotide/thiazides.
Describe the clinical presentation of someone with cholecystitis.
What is it probably caused by?
RUQ pain, fever & leukocytosis. Lies still (positive Murphy’s sign). Normal LFTs.
Mostly stones, but sometimes stenosis.
How are ultrasonography and cholescintigraphy used to diagnose stones?
Ultrasonography can visualize the stones or gallbladder thickening & edema.
Cholescintigraphy uses a radiolabeled metabolite that is secreted into bile to visualize patency.
What is Charcot’s triad, and what is it classic for?
Fever + Jaundice + RUQ pain.
Featured in acute cholecystitis (probably more accurately cholangitis because of the jaundice).
What organisms are often found in cultures in cholangitis?
E. Coli, Klebsiella, Enterobacteria and Enterococci.