Liver

• Liver

  • Largest internal gland in body
  • 1,5kg
  • 20-25cm in greatest dimension
  • Occupies whole right hypochondrium, greater part of epigastrium and extend into left hypochondrium.
• Liver function

  • Secretes bile
  • endocrine like function: modify substances into active form ( vit a,d,e,k)
  • Synthetic function: produce plasma proteins (albumin, lipoprotein, clotting factors, binding and transport proteins)
  • detofixication
  • Thermoregulation
  • Storage
  • Protein, carbohydrate and lipid metabolism

  
• External features of liver

  • Wedge shape
  • Red-brown color
  • divided into 2 main lobes: right + left
  • 2 surfaces: viceral and diaphragmatic
  • Viceral suf: superior, anterior, right and posterior
  • Diaphragmatic surface: inferior surface
  • 1 prominent border: inferior border

  
• Anatomical lobes of liver

  • Diaphragmatic surface: right and left lobes
  • Viceral surface: right, left, caudate and quadrate lobes
  • These are demarcated by attachment of: falciform ligament, fissure for ligamentum teres and fissure for ligamentum venosum

  
• Features of inferior border of liver

  • Separates anterior and inferior surfaces
  • It is rounded laterally where it separates right lateral and inferior surfaces
  • has 2 notches: notch for ligamentum ters and cystic notch (for fundus of gallbladder)

  
• Right lobe of liver

  • Much larger: 5/6 of liber
  • Contributes to all 5 suf ( sup, ant, right, post)
  • Has 2 lobes: caudate + quadrate lobes
• Caudate lobe of liver

  • Situated on posterior surface

  Boundaries:

  1. RIGHT: groove of inf vena cava
  2. Left: fissure for lig. venosum
  3. Inf: porta hepatis

  • Continuous above with superior suf
  • Connected to right lobe by caudate process
  • Bellow to the left it present small round elevation: papillary process

  
• Quadrate lobe

  • Situated on inferior sug
  • Rectangular in shape

  Boundaries:

  1. Anterior: inferior border
  2. Posteriorly: porta hepatis
  3. Right: fossa of gallbladder
  4. Left: fissure for lig. Teres

  
• Porta hepatis

  • Deep transverse fissure on inferior surface of right lobe
  • Lies btw caudate lobe above and quadrate lobe bellow

  Contains:

  1. Hepatic artery
  2. Portal vein
  3. Hepatic plexus of nerves
  4. Right and left hepatic ducts

  From behind onwards: portal vein, hepatic artery,duct

  Lips of portal vein provide attachment for lesser omentum

  
• Left lobe of liver

  • Much smaller
  • 1/6 of lives
  • Near fissure of lig venosum and its inferior surface presents a rounded evevation called omental tuberosity or tuber omentale

  
• Peritoneal relations of lives

  • Most of liver is covered by peritoneum
  • Except: Triangular bare area : on posterior surf of right lobe; limited sup snd inf by layers of coronary lig and triangular ligament.
  • Groove for inf vena cava
  • Fossa for gallbladder
• Viceral relations of liver on anterior suf

  • Extends from right costal margin to left hypochrondrium
  • Related to xiphoid process and ant abdominal wall
  • diaphragm separates and suf from pleura and lungs
  • Falciform ligament: attached to anterior suf a little right to medial plane

  
• Viceral relations of liver on superior surface

  • Shows concavity in middle: cardiac impression
  • Oj each side of impression: dome of diaphragm
  • diaphragm separates suf surface from pericardium and heart in middle and from plerua and lungs on each side.
• Viceral relations of liver on right surface

  • Related to diaphragm
  • upper 1/3: diaphragm, pleura, lungs
  • Middle 1/3: diaphragm, costodiaphragmatic recess
  • Lower 1/3: diaphragm
• Viceral relations of liver on posterior surface

  • Bare area: diaphragm, right suprarenal gland
  • Groove for inf vena cava: lodges upper part of vessels
  • Caudate lobe: crura of diaphragm above aortic opening, right and left phrenic vein
  • Fissure for lig. Venosum: lig venosum: remnant of ductus venosum in fetal life
  • left lobe: esophageal impression
• viceral relations of liver on inferior surface

  • Left lobe: gastric impression
  • Fissure for ligamentum teres: represents obliterated umbilical vein
  • Quadrate lobe: related to lesser omentum, pylorus, 1 part of duodenum
  • Fossa for gallbladder:
  • Colic impression: right to fossa of gallbladder; for hepatic flexure of colon
• Ligaments of liver

  • False ligaments: folds of viceral peritoneum: coronary lig ( attach liver to diaphragm), right and left triangular ligaments (extends from diaphragm to liver); falciform ligament (attach liver to anterior abdominal wall)
  • True ligaments: remnants of fetal structure: round ligament and ligament venosum

  
• Blood supply of liver

  • Receives blood from 2 sources: hepatic artery (oxygenated blood) + portal vein (deoxygenated)
  • Hepatic artery (20%) branch of celiac trunk
  • Portal vein (80%) branch of sup mesenteric and spleenic
  • Before entering liver both hepatic and portal vein divide into right and left branches
  • Within the liver they redivided into segmental vessels them into intralobular which then open into hepatic sinusoids. Blood from hepatic and portal vein mix and enters sinusoids, hepatocytes detoxify
• Venous drainage of liver

  Right + middle + left hepatic veins

  Drains into inferior vena cava
• Ligament of liver

  
• • functional units of liver: hepatic lobules
  • each hepatic lobule consists of
  • central vein
  • hepatocytes
  • sinusoids: porous blood vessels, drain blood from lobules into central vein
  • portal triad (hepatic vein, artery, bile duct )
• • Hepatocytes help maintain blood glucose levels: stores glycogen
  • stores a, d, e, k vitamin
  • remove amino group from AA so they can be metabolised to produce Atp
  • synthesis albumin, coagulation factors.
  • synthesises VLDL and HDL
  • regulate lipid metabolism: break down fatty acids (beta-oxidation)
• hepatic lobule can have different possible structures:

  • Classic lobule: From the hepatic arteriole and portal venule to central vein
  • Portal lobule: (direction of bile flow). Considering a triangle between 3 central veins of 3 different lobules → at the center of this triangle there will be a triad, with a bile duct. Bile flows from each pole of triangle (central vein) towards the bile duct at

  center → centrifugal direction

  
• Acinus lobule : considers the flow of oxygen rich

  blood. From portal triad to central vein: it creates zones

  • Zone 1: periportal, next to the triad. Receives the blood richest in oxygen → most resistant to circulatory problems
  • Zone 2
  • Zone 3: perivenular. Receives the blood with lowest partial pressure of O2 → will undergo necrosis and ischemia first in case of circulatory problems

  
• Lobules of liver

  
• From each pole, the hepatic artery and the portal

  vein both open into sinusoidal capillaries

  • They are fenestrated capillaries, found in the

  liver, spleen and bone marrow

  o They also contain Kupffer cells

   The sinusoidal capillaries eventually drain inside

  the central vein

  • Found at the center of the hepatic lobule

  • The blood flow is centripetal

   Many central veins from different lobules can meet

  and fuse, forming interlobular veins

   Many interlobular veins together will form the

  hepatic veins, that eventually leave the liver and

  drain inside the Inferior vena cava
• Liver ligaments