Lecture 15 Flashcards
The liver is the ____ largest organ of the body
2nd
How much does the liver weigh?
1500-2000g
What are the functions of the liver?
Detox, carb and glucose regulation, bile drainage, blood circulation and filtration, synthesis and storage of amino acids, proteins, fats, and vitamins
Is the liver and endocrine or exocrine organ?
Both
Describe the dual blood supply of the liver
1/4 hepatic artery
3/4 portal vein
Where is the liver situated?
Mostly in right hypochondrium, into epigastric region
Where is the superior boundary of the liver situated?
Ribs 5/6
What is posterior to the liver?
Oes, stomach, duodenum, R. colic flexure, R. kidney, suprarenal gland, gall bladder
Are there any structures anterior to the liver?
NO
Where is the gall bladder situated?
Costal cartilage of 9th rib at the midclavicular line
What is the falciform ligament of the liver?
Remnant of ventral mesogastrium from which the liver grew. Fold of peritoneum back on itself. Can be traced down to umbilicus.
What is the ligamentum teres of the liver?
Remnant of umbilical vein. Hard, round ligament.
What is the porta hepatis?
Doorway to the liver. Where many things enter the liver.
What attaches to the porta hepatis?
Free edge of lesser omentum attaches here, carrying structures with it
What are the three structures found entering the porta hepatis?
Hepatic artery proper, portal vein, bile duct
Where are the hepatic artery proper, bile duct, and portal vein situated in the porta hepatis?
HAP: Anterior and LHS
BD: Anterior and RHS
PV: Posterior between
What is the bare area of the liver?
An area on the superior part of the right lobe. It is where the liver presses up against the diaphragm. Peritoneum obliterated.
Where is the biggest structure in the porta hepatis?
Portal vein
What happens to the common hepatic duct in the porta hepatis?
Splits into two: R and L hepatic ducts
What happens to the proper hepatic artery in the porta hepatis?
Splits in R and L hepatic arteries
Other than blood vessels and bile duct, what else is found in the porta hepatis?
ANS fibres and lymph nodes
Will hepatic veins be found in the porta hepatis? Why?
NO
Direct drainage to IVC
What do superficial and deep lymphatics follow?
Superficial lymphatics follow venous system while deep lymphatics follow arterial system
Describe the relationship between liver and peritoneum
Apart from the bare area, liver is covered in visceral peritoneum so it is mostly intraperitoneal
What do the right and left layers of the falciform ligament create?
Right layer of falciform creates coronary ligament and left layer forms left triangular ligament
Which ligament is sharper out of the left triangular and right triangular?
Left
What are the spaces in the abdominal cavity that surround the liver?
Left and right suprahepatic space
Left and right subhepatic space
What is the blood supply to the liver?
25% hepatic artery
75% portal vein
Describe the blood from the hepatic artery and portal vein
HA: oxygenated
PV: nutrient rich but oxygen poor
Where is the arterial and venous blood conducted in the liver?
To central vein of each liver lobule by sinusoids
What are sinusoids?
Leaky areas where blood and other substances can transfuse across
What do central veins drain into?
Central veins drain into right, left, and central hepatic veins. Then directly into IVC.
How many liver segments are there?
8
Is there arterial communication between the left ad right halves of the liver?
NO
Is there mixing of venous drainage between the left and right halves of the liver?
YES. Central hepatic vein drains both left and right halves
What is special about the venous drainage of the caudate lobe?
It has a separate vein draining straight to the IVC
What does each segment of the liver possess? What does this allow?
Each segment has its own portal triad supplying it so any segment can be used for transplant and it won’t affect the rest of the liver
Lymph from the liver makes up what proportion of the total lymph in the body?
1/3-1/2
Where are the nodes situated in the liver?
Nodes at porta hepatis - celiac nodes at T12
Where does a small amount of lymph from the liver pass?
Through the diaphragm to posterior mediastinum
What is the nerve supply of the liver?
Visceral supply from coeliac plexus
- Sympathetic from greater splanchnic nerves T5-9
- Parasympathetic via tha vagus [X]
Where is pain from the liver referred to?
Epigastric region
Small amount from the diaphragm to the right shoulder.
What is the consequence of pseudomembrane formation?
Contains fluid in an abscess
What is bile secreted by? What is it stored by?
Liver
Gall bladder
How long is the bile duct? How does it end?
8 cm long. Ends by piercing medial wall of 2nd part of duodenum.
What is the bile duct joint by? What do they open into?
Main pancreatic duct. Open into Hepatopancreatic Ampulla of Vater
What does the Ampulla of Vater open into?
Duodenum via major duodenal papilla (Sphincter of Oddi)
What are the regions of the gall bladder?
Fundus hangs below liver
Body contacts visceral surface of liver
Neck joins cystic duct
What is the gall bladder covered in?
Visceral peritoneum
What are the functions of the gall bladder? What aids in these functions?
Store and concentrate bile
Folds and microvilli
What causes release of bile into the duodenum?
Fat in duodenum releases cholecystokinin from the small intestine mucosa, which causes the gall bladder to contract and release bile. Smooth muscle at distal end of bile duct and ampulla relax. Bile enters duodenum to emulsify fat.
What is the arterial supply of the gall bladder?
Cystic artery from the right hepatic artery
What is the venous supply of the gall bladder?
Cystic vein into portal vein
What is the nerve supply to the gall bladder?
ANS via the coeliac plexus (same as liver)
Where does pain from the gallbladder get referred to?
Epigastric region
Describe the lymph drainage of the gall bladder
Cystic nodes to hepatic nodes to coeliac nodes at T12
What is another name for gallstones?
Cholelithiasis
What are gallstones?
Crystalline bodies made from bile components
What is size range of gallstones?
Size sand grain to golf ball
What causes green or yellow/white gallstones?
Cholesterol from fatty diet
What causes small and dark stones?
Bilirubin and calcium salts cause pigment stones
What is choledocolithiasis?
Gallstones in the common bile duct
What is bilirubin?
Product of break down of RBC’s.
Where do gastro-omental veins lead into?
Straight into portal veins
What can cause backflow of blood from the liver?
High flow of blood going to liver. If you get areas of scarring (Hep A, B, alcohol) and loss of function, all of the blood draining into the liver will have little space to flow into. This can lead to portal hypertension. High pressure in the liver starts to create a back flow into the portal system all the way back down until it finds other veins. They tend to find their way into the systemic system.
What does portal hypertension cause?
Porto-systemic shunting: Forces blood to find another path through systemic system
What are the three main shunts?
Bottom 1/3 of oesophagus - oesophageal varices
Around umbilicus - caput medusae - forces ligamentum teres patent and blood flows through umbilical vein into superficial epigastric veins
Anus - anorectal varices - superior rectal veins into inferior and middle rectal veins.
What occurs in oesophageal varices?
Extremely dilated sub-mucosal veins. Can lead to bleeding and blood in digestive tract.
