Lecture 15 Flashcards
Size and Proportion of Liver
2nd largest organ (largest is skin)
1500-2000g (2% of body weight)
-Dual blood supply 1/4 Hepatic artery, 3/4 Portal Vein
Function of Liver
- Detoxification
- Carb and Glucose regulation
- Bile drainage
- Blood circulation and filtration
- Synthesis and storage of a/acids, proteins, fats and vitamins
- Endocrine (releasing substances into body to float around blood stream) and Exocrine(bile through ducts to other organs) function
Liver Surface Anatomy
Right Hypochondrium (most/ as Right lobe has more mass than left lobe and medial right lobe) into epigastric region. - slightly rotated around Nothing Anterior Superior boundary = Rib 5/6 Posterior surface = Oesophagus, stomach, duodenum, R. Colic flexure, R. kidney, Supra-renal gland, gall bladder Gall bladder= 9th costal cartilage level
What is the level of the Gall bladder?
Right Mid clavicular line
9th Costal cartilage (2nd to last rib)
-also makes up posterior surface of liver
Falciform ligament
Remnant of the ventral mesogastrium which liver grew, separated itself off from stomach
- connection to body wall
- runs all the way down to umbilicus
- within is Ligamentum teres (remnant of umbilical vein)
Ligamentum Teres
Remnant of umbillical vein
Hard round ligament
running within Falciform ligament
Porta Hepatis
“doorway to liver” (essentially hilum of liver)
-where major structures enter and exit
Free edge of lesser omentum attaches here (carrying structures with it)- Foreamen of Winslow. HeptoDuodenal
Artery= Most Anterior & LHS (aorta is on left side). Pinky/red
Bile Duct (technically common hepatic)= Anterior & RHS (gallbladder on right side). Green
Portal Vein= Posterior (between). Largest structure of three. Blue.
Common Hepatic Duct- splits in two when enter Porta Hepatis: Right and Left Hepatic Ducts
Proper Hepatic artery also splits
Also on arteries will have ANS fibres and lymph nodes (superficial lymphatics follow venous system, Deep hepatics follow arterial system)
-Will not find hepatic veins-direct drainage into IVC
Lobes of Liver
Left
Right
Quadrate lobe = Anteriorly between Gall bladder and Left lobe
Caudate lobe = Posteriorly and superiorly between IVC and left love
Bare area
where liver is pressed up against diaphragm
Obliterates the peritoneal coverings (now has no peritoneum)
+ ligaments
Correlations between Arteries and Lymphatics
Deep lymphatic - Arteries
Superficial lymphatics - Veins
Liver movement with breath
displaces lung on right side. On exhaled breath, liver invades into lung fields severly
When diaphragm flattens pushed liver down into abdominal cavity
-Increases abdominal pressure.
Allows lung to inflate
Liver Peritoneum
Liver grew in ventral mesogastrium as hepatic bud-
Intraperitoneal - Apart from area attaches to diaphragm/Bare area, liver covered in visceral peritoneum (as is gall bladder)
Peritoneum folds back on itself to make falciform and R&L triangular ligaments
Falciform ligament passes to the umbilicus and contains the remnants of the umbilical vein (ligamentum teres)
Right layer of the falciform creates coronary ligament and left layer forms left triangular ligament
Ductus venosis - oxygenated blood –> to IVC
Peritoneal Ligaments
Right lobe:
Coronary ligament (crown/wreath)
Right triangular ligament (folding back of the coronary ligament - onto diaphragm and body wall as parietal peritoneum. Forms right triangular ligemnt)
Falciform ligament (fold of peritoneum back on itself) + Ligamentum Teres
Left lobe:
Ligamentum venosum (remnant of Ductus venosus - embryological remnant: shunt going straight into IVC - as umbilical vein goes straight into liver
-Peritineal folds between Left lobe and Caudate lobe
Left triangular/coronary ligament
Ductus Venosus
Oxygenated blood –> IVC
- Ligamentum venosum is a remnant of Ductus venosus - embryological remnant: shunt going straight into IVC - as umbilical vein goes straight into liver
- Still Peritineal folds between Left lobe and Caudate lobe
Peritoneal cavities around Liver
Pertinoneum reflects back on itself and against body wall
-where
Right Suprahepatic space
Right Subhepatic space
-shows Gallbladder bound to liver, under same peritoneal covering, due to growing in same mesentery
Left Suprahepatic space (really comes over liver as thinner/less mass)
Left Subhepatic space
- all important for pain referal
Blood supply to Liver
2% Hepatic Artery -Oxygenated
75% Portal Vein -Nutrient rich (from digestive tract) - to be processed and detoxified
Arterial and Venous blood are conducted to central vein of each liver lobule by sinusoids
Sinusoids: Leaky areas, blood can transfuse across, other substances can diffuse across. Where terminal ends are meeting venous drainage. –>
Central veins (from sinusoids system)/Sinusoids drain to –> R, L & Central hepatic veins (important for physiological segmentation. Varies-sometimes get 2x hepatic arteries)
-then directly to IVC (to heart for processing)
Sinusoids
Leaky areas, blood can transfuse across, other substances can diffuse across. Where terminal ends are meeting venous drainage.
-Arterial and Venous blood are conducted to central vein of each liver lobule by sinusoids
Liver Segments
Within anatomical lobes, there are separate subunits which are functionally and physiologically distinct - important for cancer etc
Couinaud Classification -radiologically important
Right and left physiological lobes:
-not morphological lobes
-part of Right lobe forms left physiological lobe
-1 is part of Left physiological lobe
- arterial supply splits into Left and Right branch of Hepatic artery
-Right Posterior and Anterior section + Left Medial and Lateral
-No arterial communication between Left(supplied by left branch) and Right (supplied by right branch) halves of liver
Venous drainage = Hepatic Veins (draining into IVC)
-Left, Right & Central Hepatic veins
-some mixing between the halves at this point as central drains both left and right
-Caudate Lobe has separate vein draining straight into IVC
-Posterior region 6-7 in right hypochondrium- sit behind 8 and 5
-Between each lobe- each lobe has own portal triad supplying it- Branch of Portal vein, Hepatic duct, Artery
-therefore you can take out a lobe, w/o effecting function of liver
-Central hepatic vein will drain both left and right physiological lobes
How do you differentiate lobes in radiology
position of portal and hepatic veins
Left Portal vein higher than right
Lymphatic drainage of the Liver
Lymph from liver = ~1/3-1/2 of total body lymph (generating so many lymphatics as so many nutrients and processes occurring)
Nodes of porta hepatis –> Pre-aortic Coeliac nodes T12
Small amount passes through diaphragm to Posterior Mediastinum (in thorax)
ANS of the Liver
Visceral supply from coeliac plexus
- Parasympathetic via the Vagus {x}
- Sympathetic from the Greater Splanchnic nerves T5-9
Pain = referred to epigastric region
-small amount via diaphragm to Right shoulder and neck- due to relationship with diaphragm - which gets C3-5. Some C5 fibres are autonomic - can breath without thinking
Areas of Abcess surrounding liver
paracolic gutters. fluid moves around abdominal cavity as you stand up and down, resulting in abscesses in site far distant from cause
- Suprahepatic spaces are great spaces for fluid to gather and build
1. Right subhepatic
2. Right suprahepatic
3. Anterior to liver
4. Left subhepatic
5. Left suprahepatic
6. Posterior to liver - Fluid sitting somewhere long enough, results in pseudomembranes binding the abcesses - now contained- therefore can no longer move around
- Think where pain will present- re where it is contacting (body wall or diaphragm, liver etc)/ Autonomic System
Liver Supply overview
Blood:
Arterial Supply: 25% Hepatic Artery Proper
Venous Supply: 75% Portal Vein
Venous Drainage: Hepatic Veins into IVC
Nerve: ANS via Celiac Plexus
- Parasympathetic= Vagus CX
- Sympathetic= Greater Splanchnic T5-9
Lymph= Coeliac Nodes T12
Biliary Tree
Bile secreted by liver (continuously) and stored by gall bladder
-rats dont have gall bladder, eat all time so bile always secreted into SI to emulsify fats. Humans not eating all time, so need to store and concentrate bile, so when we eat fatty food- get really strong concentrated burst of bile
Bile duct 8cm long and ends by piercing medial wall of 2nd Descending part of duodenum
Common Bile Duct = Common Hepatic Duct + Cystic Duct
-descends posterior to duodenum and posterioly pierces into pancreas
Joined by main pancreatic duct and open into Hepatopancreatic Ampulla of Vater
Ampulla of Vater = Common Bile Duct + Pancreatic Duct
Ampulla opens into duodenum via major duodenal papilla (Sphincter of Oddi)
-Sphincter=muscle. Ampulla=swelling. Papilla=process inside duodenum
