15 - Liver, Biliary and Portal System Flashcards
What is the 2nd largest organ in the body?
Liver - makes up 2% of your body weight (1500-2000g)
What are some of the functions of the liver?
- detoxification
- carb and glucose regulation
- bile drainage
- blood circulation and filtration
- synthesis and storage of amino acids and proteins, fats and vitamins
What is the livers blood supply?
Dual
1/4 from the hepatic artery
3/4 from the portal vein
Where is the liver?
On the right hand side pushing up under the diaphragm at rib 5-6 (fundus of stomach is around rib 5-6 as well - liver can push a bit higher)
What is the most anterior, superior and lateral structure?
The liver - all other organs are posterior and inferior to the liver i.e. oesophagus and duodenum/pylorus of stomach, right colic/hepatic flexture of the colon behind the liver
Where does the gall bladder sit?
Behind the inferior of the right lobule - originate from same hepatic outgrowth
> sitting at 9th costal cartilage on the RIGHT hand side in the MID clavicular plane
Anterior surface of the liver?
Large right lobe, small triangular left lobe
> falciform ligament sits between the left and right lobules
Falciform ligament?
sits between the left and right lobes - reminent of verntal mesogastrium that the liver grew in
> goes from the body wall to the liver
Which lobe is bigger?
right
Where is ligamentum teres and what is it?
At the free end of the falciform ligament
Reminent of an umbilical vein
Gross morphology of the posterior inferior surface?
- IVC in middle superiorly
- 2 extra lobes;
> caudate lobe > IVC > right lobe
> quadrate lobe > gall bladder > right lobe
What is left to the IVC?
Caudate Lobe > right lobe
What is left to the gall bladder?
Quadrate Lobe > right lobe
Structures rotating and pressing round and start to press against body wall and obliterate peritoneum (large bowel becomes retro…) … how does this occur in the liver?
Liver pushing against diaphragm and obliterates peritoneum and get bare area of the liver not covered in peritoneum
What area of the liver is NOT covered in peritoneum?
The superior posterior right lobe beneath the diaphragm
Porta hepatis?
Doorway to liver - how structures get in and out (like hilum). In free edge of the lesser omentum (hepatoduodenal ligament) carries the portal triad
The portal triad are 3 structures which enter the …
porta hepatis
Porta hepatis??
Free edge of the lesser omentum attaches to the porta hepatis, carrying structures with it
What order are the structures in?
Portal vein - most posterior (with IVC) and inbetween artery and bilde duct
Hepatic Artery - left and anterior (like aorta)
Bile Duct - right towards liver/gall bladder and most anterior
How do the vessels divide?
Split as come in to liver (bile out)
- R & L hepatic ducts joint into the common hepatic duct as enters liver
- portal vein splits into L & R portal vein
- proper hepatic artery splits
What else will you find with the portal triad/porta hepatis?
ANS fibres and lymph nodes
Where are the hepatic veins?
Wound find them - are in the liver and have direct drainage into the IVC
anterior boundary of omental foramen?
portal triad - portal vein closest (most posterior)
What shape is the liver?
Wedge shaped
Where does the liver develop and why is this important?
In ventral mesogastrium - means it is completely covered in peritoneum (except bare area - attached to diaphragm - where it is reflected up onto the diaphragm)
Why is the peritoneum important at the liver?
Potential spaces and fluid migration
How are the falciform and right and left falciform ligaments formed?
the peritoneum folds back onto itself
Falciform ligament?
Runs from anterior/umbilicus to the body wall in between the right and left lobes carrying with it the ligamentum teres (reminent umbilical vein)
Where are the triangular ligaments?
Where the peritoneum reflects up onto the diaphragm on the left and right sides
Ligamentum venosum?
Runs betwen caudate lpbe and left lobe - reminent of ductus venosus - shunt vessel straight to IVC (umbilical blood from placenta doesn’t need to go to liver as is not functional as mother detoxifies)
What are the potential spaces?
Formed by the peritoneum folding around the liver
2x suprahepatic
2x subhepatic
> the right sub-hepatic space (pouch of Morrison) is most clinically important. Separates liver from right kindey and is important in finding fluid in the abdomen
What do you need to know about every organ?
Blood, nerve, lymphatics
Blood supply to liver?
25% hepatic artery proper (O2 rich)
75% portal vein (nutrient rich)
How is the blood conducted to the liver?
The hepatic artery PROPER and portal vein blood is conducted to the central vein of each liver lobule by SINUSOIDS
Sinusoids?
Bloods vessels containing the mixed blood of the hepatic artery and portal vein. Feed into the central vein
> from the left and right branches of the veins and arteries
> leaky areas of the liver where blood is filtered
Where do the central veins drain to?
The left, right and central hepatic veins and then DIRECTLY into the IVC
How many veins are there going into the liver and how many coming out?
Right and left portal veins in, right, left and central hepatic veins coming out into IVC
How many segments/physiological lobes can you divide the liver into?
8 segments
Is there communication between the left and right sides of the liver?
NO
> hepatic artery comes in and splits into R&L there is now NO COMMUNICATION between the sides supplied by each of these arteries
> each segment will have 1 bracnh of the bile duct, artery and vein and they DO NOT COMMUNICATE
How is the fact each segment does not communicate with another clinically important?
Own branch of artery, vein and bile duct. They are functionally distinct and independent. Basis of liver transplant - can remove and wont affect function of other segments (don’t interrupt blood flow)
Also contains infections and tumours
Caudate Lobe venous system?
Drains straight back into IVC NOT the hepatic veins
Where IS there some mixing between the right and left lobes?
During venous drainage - the right, left and central hepatic veins DRAIN the liver into the IVC
> the central hepatic vein drains BOTH the left and the right
ANS supply?
Follows blood supply - from the Coeliac trunk so ANS is from the Coeliac plexus
> parasympathetic from vagus and sympathetic from greater splanchnic nerves T5-T9 (ALL FOREGUT)
> pain refers to the epigastric region and small amount via diaphragm to the right shoulder/chest
Where does pain in the liver refer to?
Foregut so to the epigastric band (and small amount via diaphragm to the right shoulder/chest)
> right upper quadrant
> main gut tube centralises at the band, liver can be focused more to right as have 2 chains of sympathetic ganglia so get innervation into one side of column so registers more to one side
(still in epigastric band but more focused to right side)
Lymphatic drainage of the liver?
- lymph from the liver makes up 1/3 - 1/2 of the total body lymph
- nodes at the porta hepatis to the coaliac nodes at T12 (where artery came off - foregut)
- very little amount through diaphragm with IVC
For the liver, why can you also get pain referred to the right shoulder/chest as well as the epigastric area
Because it is pushing up against the diaphragm and irritates the phrenic nerves (C3-C5 dermatome)
Potential spaces?
ability for fluid to migrate and cause problems
Pseudo-membranes?
Fluid/pus/blood gathers in a spot > pseudo membranes > abscess > protects from outside world > can keep growing if bacteria as protected by wall of dead blood cells
Should there be a space between liver and diaphragm/kidney?
No. Have free fluid in abdomen - abscess?
Ans via
Coeliac plexus
Parasympathetic via
vagus (X)
Sympathetic
Great splanchnic T5-T9 (MAKES SENSE TO DERMATOME AND PAIN REFERRAL)
Lymph to
Celiac nodes at T12
3 parts of the gall bladder?
Fundus - hangs down below liver
body - contacts visceral surface of the liver
neck - joins the cystic duct
Is the gall bladder covered in peritoneum?
Yes - grew in ventral peritoneum and is covered in visceral peritoneum (intrap.)
Function of gall bladder?
Store and concentrate bile
Why doesn’t rat have gall bladder?
Constantly eats and releases liver into gut tube to emulsify fat. We do not usually eat regularly. Have enough bile to emulsify digest the fat in your meal
What stimulates the gall bladder to contract and release bile into the duodenum?
Fat in the duodenum stimulates cholecystokinin release which stimulates contraction
> the smooth muscle at the distal end of the bile duct at the ampulla relax allowing bile into the duodenum
can you live without a gall bladder?
yes not as efficient - just releases bile directly from liver
Where is bile made?
Liver > connected by pipes to gall bladder where it is stored and both connected to duodenum
How long is the bile duct?
8cm
How does the bile duct end?
Pierces 2nd part of duodenum where original hepatic stalk came off
How do the biliary tree and pancreatic system join?
The main pancreatic duct opens into the hepatopancreatic ampulla of Vater
> opens into the duodenum by the major doudenal papilla (sphincter of Oddi)
Where do the joint pancreatic and biliary systems enter into the duodenum?
The hepatopancreatic ampulla of vater opens into the SECOND part of the duodenum by the major duodenal papilla/sphincter of Oddi
Where does the bile duct travel?
BEHIND the duodenum
Blood/nerve/lymph to gall bladder?
CYSTIC (‘fluid filled sac’)
Arterial: Cystic artery from right hepatic artery passing through the Triangle of Calot
Venous: Cystic vein into portal vein
Nervous: ANS via Coeliac plexus pain to epigastric
Lymph: Cystic nodes > hepatic nodes > coeliac nodes at T12
Arterial supply to GB
Cystic artery from the right hepatic artery which passes through the triangle of calot
Venous GB
Cystic vein to portal vein
ANS of GB
Via coeliac plexus pain to epigastric
Lymph to GB
Cystic nodes > hepatic nodes > coeliac nodes at T12
What forms the triangle of calot and what passes through it?
Common hepatic duct, cystic duct and liver
> cystic artery passes through
What colour are cholestrol gallstones?
Creamy yellow/green
What are gallstones called?
cholelithiasis
What are gallstones?
- crystalline bodies made from bile components
- can be pigment stones i.e. bilirubin and calcium salts, usually small and dark
Bilirubin?
- pigment stones
- normal breakdown product of RBC
- abnormal liver behaviour > won’t break down > too much bilirubin > yellow in jaundice/yellow green bruising > gallstones
CholeDOCOlithiasis?
Gallstones in the common bile duct
Portal system?
IMV joins splenic v joins SMV forming portal vein
Where is the portal vein formed?
behind the neck of the pancreas at the L1 plane/L1 transpyloric plane (where pylorus of stomach, 1st part of duodenum, SMV/SMA
What plane is the transpyloric plane on and what sits on it?
L1 - SMV/SMA, pylorus of stomach, first part of duodenum, portal vein behind the neck of the pancreas
What do all of the abdominal viscera drain to (incl spleen)? Why is this important?
Portal vein
Portal system fails > backflow of blood due to pressure changes
What are the 3 main shunts of of the porto-systemic system during portal hypertension
Forces blood to find another path through the systemic system
1. Bottom half of the oeosophagus through left gastric veins > SVC
> oesophageal varices
2. Around umbilicus via ligamentum teres/umbilical vein > epigastric veins > IVC
> caput medusa
3. Anus via the inferior mesenteric and superior rectal veins back into iliacs/femoral and IVC
> anorectal varices
