Gall bladder disease - pathology Flashcards
Anatomy:
- Label the parts of the gall bladder
Anatomy:
- Label the ducts
Anatomy:
- Label the openings into the duodenum
Physiology
- What is bile made out of?
Micelles
- Bile acids/salts
- Phospholipids (lecithin)
- Cholesterol
Bile pigments
- Bilirubin
- Biliverdin
Water, electrolytes (Ca2+), bicarbonate (HCO3-)
Physiology: bile acids/salts
- Where are they made?
- What are they made from?
- Difference between bile acid/salt?
Made in the liver, from cholesterol.
Acid has H+, salt doesn’t.
Physiology: micelles in bile
- How do they form?
Amphipathic bile salts (or acids) and phospholipids surround cholesterol (non polar)
Physiology: fat metabolism
- Describe the role of cholecystokinin and secretin
Physiology: fat metabolism
- Describe how bile aids in fat digestion
- Bile salts and pancreatic lipase are released via the Ampulla of Vater/ Sphincter of Oddi into the duodenum
- Bile salts emulsify fat (triglycerides) into smaller particles (micelles)
- This assists pancreatic lipase to hydrolyse the triglycerides into glycerol + fa’s
Physiology: fat metabolism
- Where are bile salts reabsorbed?
In the terminal ileum
Gall stones
- 3 types?
- Cholesterol stones
- Black pigment stones
- Brown pigment stones
Gall stones: cholesterol stones
- Composition?
- Mechanisms of formation
Precipitated cholesterol, may be bound to calcium carbonate
Cholesterol is precipitated due to
- Too much cholesterol
- Not enough bile salts/acids + phospholipids
- Gall bladder stasis (can lead to cholesterol falling out)
Gall stones: cholesterol stones
- Risk factors?
- Female: high oestrogen levels
- Fertile: high estrogen levels in pregnancy, OCP
- Fat: obesity associated with increased cholesteorl
- Fair: white people
- Forty
- Rapid weight loss (eg. following bariatric surgery) increases cholesterol levels in bile
- Drugs: octreotide, ceftriaxone
Gall stones: black pigment stones
- Composition?
- Mechanism of formation?
Calcium bilirubinate (bilirubin is unconjugated)
At bile pH, unconjugated bilirubin is an anion. It can either bind to bile salts, or Ca2+
When there is too much unconjugated bilirubin levels, or not enough bile salts, this favours bilirubin binding with Ca2+ –> calcium bilirubinate
Gallstones: black pigment stones
- Risk factors?
Excess bilirubin
- Prehepatic: chronic haemolysis
- Intrahepatic: liver cirrhosis, Gilbert’s syndrome
Bile salt malabsorption
- Terminal ileal diseases eg. Crohn’s disease
-Terminal ileum resection
Gallstones: brown pigment stones
- Composition?
- Mechanism of formation?
- Where does it often form?
- Risk factor?
Calcium bilirubinate (also unconjugated bilirubin)
Occurs due to infection
Bacteria have hydrolytic enzymes which hydrolyse conjugated bilirubin (deconjugating it) and phospholipids; both combine with Ca2+ –> precipitate as the stone.
In the bile ducts, unlike the gall bladder (more common for the latter two)
Asian populations - some agents of gallbladder infections (eg. Ascaris lumbricoides) are endemic to Asian countries