Lecture 6 Flashcards
What are the main functions of the liver?
detoxification
protein synthesis
production of bile – accessory GI organ
glycogen storage
Where is the liver positioned in relation to other organs
below diaphragm
right wrt stomach
above the colon
overlies gallbladder
What are the four main lobes of the liver?
Left, right-Ant
Quadrate and caudate-Post
What are the ligaments related to the liver and what do they separate
Falciform (ant) and lesser omentum (post) ligaments separate right and left lobes
What does the porta hepatic divide?
quadrate and caudate lobes
Name the four peritoneal folds and its relevant linkage
Falciform ligament- Links diaphragm to upper surface liver ligamentum teres (aka round ligament) at lower end
Round ligament
obliterated left umbilical vein
extends to umbilicus
Coronary ligaments
links diaphragm to live
Lesser omentum
links liver to stomach
Describe the lesser omentum
From lesser curvature stomach to porta hepatis
Has a free margin (ventral mesentery)
Encloses hepatic artery portal vein bile duct lymph vessels
Close to the stomach it also encloses the gastric arteries and veins
what is the blood supply for each region of the gut?
Foregut – coeliac artery / trunk
Midgut – superior mesenteric artery
Hindgut – inferior mesenteric artery
Describe the blood supply to the liver
Coeliac artery (aka trunk or axis)
left gastric
splenic
hepatic
T12/L1 Level
Also supplies
duodenum
pancreas
No similarly named
vein
What are the most common variations in the hepatic artery?
Most common cases:
right hepatic artery replaced to the SMA
left hepatic artery replaced to the left gastric artery
trifurcation of the common hepatic artery:
right hepatic artery
left hepatic artery
gastroduodenal artery (GDA)
Describe the ports hepatis
Entry / exit point for hepatic portal vein hepatic artery proper common hepatic duct nerves and lymphatics
Once in: branching of vessels (and ducts) and leads to Division of liver into lobes and segments
What does the septic artery carry?
Oxygenated blood
What does the portal vein carry and what two vessels form it?
Portal vein (sup mesenteric + splenic) deoxygenated blood nutrients drugs toxins
What does shelver anatomic lobes subdivide into?
Segments (Couinaud)
What does the hepatic artery and portal vein branch into?
Sinusoids
What is the term used to the collective of the bile duct, hepatic artery and portal vein
Portal triad
Describe the functional anatomy of the liver lobules
Each lobe of liver contains several lobules
Lobules: the functional units of the liver
Contain hepatocytes (60% liver cells)
Hepatocytes also secrete bile
Portal triads at corners
What is the metabolic function of the hepatocytes?
Synthesis and release plasma proteins into blood
albumin
clotting factors complement cascade components
Deaminates amino acids – urea into blood
Bilirubin to bile pigment
Bile salts – emulsification of fats
Describe the venous drainage of the liver
The ‘mixed’ blood from the two sources (portal and hepatic) in the sinusoids passes through the hepatocytes and into the central vein
The central vein is found at
the center of a hepatic lobule
Central veins then drain into
the sublobular vein
Sublobular vein then drain
into hepatic veins
Describe the portocaval anastomosis
Communications between some branches of the portal and systemic systems
Very important if portal vein blocked or passage via liver meets resistance – portal hypertension
Allow collateral return of blood to heart without which subject would die
Abdominal part of oesophagus – left gastric tributaries with oesophageal branches azygos
Anal canal – superior rectal anastomoses with middle and inferior rectal
Umbilicus – paraumbilical veins with epigastric veins
Veins of colon, duodenum, pancreas, liver with renal, lumbar and phrenic
Describe portal hypertension
Obstruction of portal vein
Pressure rises – hypertension
Anastomoses between portal and systemic means backflow of blood to heart then lungs
Signs:
Varicoses
Caput medusa ; oesophageal varices
Describe the portocaval shunt
Reduction of hypertension
Divert blood from portal to systemic
Blood diverted from portal to IVC
Portal vein conveys 70% blood to liver
Largely been abandoned since the advent of TIPS (transjugular intrahepatic portosystemic shunting)
Describe bile and its flow
Secreted by hepatocytes into bile canaliculi
Closed sphincter Oddi to duodenum => bile flows to gall bladder to be stored and concentrated
Right and left hepatic ducts – relevant lobes
Emerge from porta – unite to form common hepatic duct
(more in next lecture)
describe the lymphatic drainage
Liver produces vast amount of lymph
Lymph nodes in porta hepatis
Pass to coeliac nodes
Drain to cisterna chyli
