Anatomy of the liver Flashcards by Adele Atkins

Where is the liver located?

Located below diaphragm: mostly the right hypochondrium & epigastrium, but extends into left hypochondrium
Below diaphragm
Right wrt stomach
Above the colon
Overlies gallbladder
Top part of liver in between the 4th and 5th rib on the right hand side. Liver has ribs covering it

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State the main functions of the liver

detoxification
protein synthesis
production of bile – accessory GI organ
glycogen storage

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Describe the intensity of the blood supply of the liver

Highly vascularised

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Describe the shape and colour of the liver

Wedge shaped reddish/brown organ

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Describe the structure of the liver

Diaphragmatic upper surface blunt, dome shaped/ sharp inferior border
Ant. view – divided into two main lobes: left and right
Post. view – two other lobes: quadrate and caudate
Surface covered by peritoneum except bare area, where it connects with diaphragm
Falciform (ant) and lesser omentum (post) ligaments separate right and left lobes
Porta hepatis divides the quadrate and caudate lobes

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List the peritoneal folds

Falciform ligament
Round ligament
Coronary ligaments
Lesser omentum

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Describe the falciform ligament

Links diaphragm to upper surface liver 
Ligamentum teres (aka round ligament) at lower end

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Describe the round ligament

Obliterated left umbilical vein

Extends to umbilicus

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Describe the coronary ligaments

Links diaphragm to liver

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Describe the lesser omentum and its function

Links liver to the stomach - 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

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What do all the blood supply to the gut have in common?

All from the midline at the abdominal aorta

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Which artery is derived from the foregut?

Coeliac artery/trunk

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Which artery is derived from the midgut?

Superior mesenteric

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Which artery is derived from the hindgut?

Inferior mesenteric

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Describe the blood supply to the liver

Coeliac artery (aka trunk or axis)

Left gastric
Splenic
Hepatic

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Which vertebral level does the coeliac artery divide?

T12/L1 Level

What other structures does the coeliac artery supply?

Duodenum

Pancreas

Describe the hepatic artery variations

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 porta hepatis

At hilum of the liver- visceral surface
Deep fissure
Entry/exit point for
- hepatic portal vein
- hepatic artery proper
- common hepatic duct
- nerves and lymphatics

What reaches the liver through the hepatic artery?

Oxygenated blood

What reaches the liver through the portal vein?

Deoxygenated blood
Nutrients
Drugs
Toxins

What is the portal vein composed of?

sup mesenteric + splenic

What is a portal triad?

According to how the hepatic artery and portal vein subdivide, the liver anatomic lobes are subdivided into segments (Couinaud)

Branches of hepatic artery and portal vein carry blood into sinusoids

Branches of the bile duct accompany those of the hepatic artery and portal vein. All three structures are called portal triad and supply each segment

Why is knowledge of coinauds segments important?

Knowledge of vascular supply to segments is vital for liver transplants or surgery

Describe liver lobules

``` Each lobe of liver contains several lobules Functional units of the liver Hexagon shaped Contains hepatocytes (60% liver cells) Portal triads at corners ```

Describe the metabolic functions of 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 portal systemic anastomosis and why they are important

Communications between some branches of the portal and systemic systems aka portocaval anastomosis 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

List some portal systemic anastomosis

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

What is portal hypertension?

Common clinical condition caused by obstruction of portal vein Pressure rises – hypertension Anastomoses between portal and systemic means backflow of blood to heart then lungs Signs include: Varicoses, Caput medusa ; oesophageal varices

Describe a portacaval shunt

Procedure carried out in attempt of 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 the pathway and secretion of bile

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

How much bile is secreted in an hour?

40ml

Describe the lymphatic drainage of the liver

Liver produces vast amount of lymph Lymph nodes in porta hepatis Pass to coeliac nodes Drain to cisterna chyli

Describe the risk of liver trauma

Closely related to lower ribs Fracture ribs / penetrating wounds High vascularisation => severe haemorrhage Remove portions due to segmental nature liver and vessels / ducts supplying it liver biopsies metastatic spread cirrhosis