Gall-bladder and Liver physiology Flashcards
Which lobe of the liver is the gall bladder associated with?
The gall bladder is found on the visceral surface of the liver, and is associated with the Quadrate lobe.
Explain the surface anatomy/ positioning of the gall bladder in relation to the MCL.
The fundus of the gall bladder is found in the Right- MCL inferior to the 9th costal cartilage.
Note that the fundus of the gall bladder is found lower than the anteroinferior border of the liver.
What is the function of the gall bladder?
The gall bladder is a 50ml reservoir of bile
What is the innervation of the gall bladder
Autonomic nervous system
What is the blood supply of gall bladder?
Coeliac trunk Common hepatic artery Hepatic artery proper Right hepatic artery Cystic artery
What is the venous drainage of the gall bladder?
Cystic vein
Portal vein
True or false:
- Conjugated bilirubin is normally found in urine.
False
True or false
- Bile contains digestive enzymes.
False
What are substances stimulating bile secretion called?
Choloretics
What are the contents of bile?
Bile salts
Bile pigment
Cholesterol
Steroid hormone
What are the 2 main components in bile salt formation?
Cholesterol
Amino acids.
Name 4 functions of bile acids:
- Involved in digestion and absorption of fat.
- Regulate their own synthesis from cholesterol, by hepatocytes
- Function as choleretics (Substances stimulating bile secretion)
- May increase colon motility/ laxative.
Name the 2 primary bile acids (sterols synthesized from cholesterol):
- Cholic Acid
2. Chenodeoxycholic acid.
Name 2 secondary bile acids (conjugated amino acids):
Glycine
Taurine
Primary bile acids are conjugated into secondary bile acids.
Use this to describe the formation of bile salts
Cholic acid and chenodeoxycholic acid are sterols synthesized by hepatocytes from cholesterol.
They are then conjugated into amino acids Glycine and Taurine to form soluble glycocholic acid and taurocholic acid.
Glycocholic acid and taurocholic acid are secreted and react with Na+ or K+ to produce bile salts.
Name the 3 intermediates that bile salts must consist of:
Primary bile acids: cholic acid and Chenodeoxycholic acid
Secondary bile acids: Glycine and taurine
Na+ or K+
Name 4 functions of bile acids
- Increase colon motility/ laxative
- Fat metabolism (Absorption and digestion of fat)
- Regulate their own synthesis from cholesterol by hepatocytes
- Function as choleretics.
What portion of primary acids are converted into secondary bile acids but intestinal bacteria?
25%
Name the 2 primary bile pigments and mention, what compound are they derivatives of?
Bilirubin
Billiverden
Both of which are a derivatives of haemoglobin
What plasma protein is bilirubin bound to, in blood?
Albumin
Name 2 other compounds that bile pigments are derived from:
Myoglobin
Cytochromes
Name the carrier of bile pigments in the liver:
Glucuronic acid
What is jaundice?
Jaundice is medical condition in which there is excessive bile production, ineffective bile excretion or obstruction of the bile duct leading to a build up bilirubin the body.
As a result, the skin, sclera and mucous membranes develop a yellow appearance
What enzyme catalyzes conjugation within hepatocytes
Glucuronyl transferase
What is the cause for neonatal jaundice?
There’s is impaired glucuronide formation due to transferase deficiency
Which drug increases bile duct pressure?
Morphine
Which drug stimulates glucuronyl transferase activity?
Phenobarb
What is bilirubin broken down into in the intestines causing brown discoloration of faeces?
Stercobilin
What is urobilin?
This is the remainder of the pigment that is reabsorbed and excreted by the kidneys
What happens to bilirubin excretion in the case of hepatitis.
With hepatitis, excretion fails and jaundice results.
Which duct connects the gall bladder to the common hepatic duct
The cystic duct.
What epithelium in found lining the internal mucous membranes?
Simple columnar epithelium
What is the main function of the gall bladder?
Store bile
During inter digestive periods, the sphincter of Odi closes.
Bile flows into a relaxed gall bladder
Mucosa reabsorbs water and electrolytes rapidly
What hormone stimulates gall bladder contraction?
Cholescystokinin
What are the 2 mechanisms that control gall bladder contraction?
Neurological
Chemical
Name the 2 mechanisms that control gall bladder contraction?
Neurological:
- Stimulation of the vagus nerve causing the contraction of the gall bladder and relaxation of the sphincter
Chemical:
- when chyme reaches the upper small intestines, fatty acids and protein products stimulate the release of cholecystokinin
Cholecystokinin is a hormone that stimulates the contraction of the gall bladder
What are the main components of gallstones ?
Calcium.
Bilirubinate.
How do gallstones form?
If Billirubin glucuronide is deconjugated, the free billirubin combines with calcium to form calcium bilirubinate which is highly insoluble.
What is hepatic regeneration?
Ability of the liver to regenerate is highly effective.
True or False:
- Conjugated bilirubin is normally found in urine.
False.
True or False:
- Intrahepatic cholestasis is an indication for surgery.
True
True or False:
- Gall-stones can cause extra-hepatic cholestasis.
True.
True or False:
- Gilbert syndrome produces ↑ed conjugated bilirubin.
True
True or False:
- Obstructive jaundice produces dark stools.
False.
True or False
- Obstructive jaundice is always extra-hepatic.
False.
True or False
- Obstructive jaundice may result in cholangitis.
True
True or False
- Hemolysis results in ↑ed unconjugated bilirubin.
True.
True or False
- Hemolysis results in light stools
• intra-hepatic cholestasis may be related to hepatitis T
False
True or False
- Intra-hepatic cholestasis may be related to hepatitis.
True.
True or False:
- Intra-hepatic cholestasis may be related to hepatitis.
True.
What is the embryological derivative of the falciform ligament?
Remnants of the ventral mesogastrium
What is the embryological derivative of the ligamentum teres hepatis/ round ligament?
Obliterated umbilical vein
What is the embryological derivative of the ligamentum venosum
Ductus venosus
Name, in order, the structures needle will pierce in a liver biopsy:
Skin. Fascia. Intercostal space. Diaphragm. Parietal peritoneum. Visceral peritoneum. Liver.
Explain bile pigment formation:
In the macrophage: RBC death produces heme + globin+ iron Heme converted to biliverdin and Heme reduced to bilirubin Bilirubin is water insoluble Bilirubin binds to albumin which transports it to the liver
In the liver:
Bilirubin + glucuronic acid is conjugated to bile salts by glucoronyl transferase to mono- or diglucuronide
Which is transported via the biliary duct system through the duodenum
Into the small intestines deconjugated by β glucuronidase
And large intestines where bacterial oxidation occurs and it is excreted as stercobilinogen (in faeces)
The rest of the 2-5% urobilinogen is re-absorbed via the blood stream into the kidney
And then excreted as urobilin
20% into enterohepatic circulation
What causes unconjugated bilirubinaemia?
Haemolysis
Gilbert’s syndrome
Criggler Najar Syndrome
