1. The Liver
Anatomy
Right (middle hepatic vein) Left lobe
Right – caudate & quadrate lobes
Overall, 8 subdivisions separated by R, middle & L hepatic veins
Each section has portal pedicle – individual resection
Blood flow:
Hepatic/Portal Vein
Portal Tracts
Sinusoids
Branches of Hepatic Veins (finally form 3)
IVC
Lymph – formed in the perisinusoidal space collected in lymphatics in portal
tracts eventually draining into hepatic ducts
Acinus – functional liver unit. Made of parenchyma supplied by portal tracts
containing portal vein radicles, hepatic arterioles and bile ductules.
Sinusoids – a small blood vessel without a continuous endothelium
(fenestrated) or basement membrane and has Kupffer cells (phagocytic).
They are separated by hepatocytes.
Kupffer cells – secrete Ils, TNF, collagenase & lysosomal hydrolases
Space of Disse – the subendothelial space between sinusoids and
hepatocytes. It contains a basement membrane matrix and stellate cells.
Stellate cells – contain desmin. Are activated to myofibroblasts which
contract and regulate sinusoidal blood flow. Involved in fibrosis.
Blood Supply:
Hepatic Artery – from celiac axis (25% blood flow
Portal Vein – drains most of GI tract and spleen (75%
of blood flow)
Enter via porta hepatis
Caudate Lobe blood:
Receives an independent supply
via the portal vein and hepatic
artery and drains directly into the
IVC
2. Liver Function:
Protein Metabolism
Synthesis & Storage:
Makes all circulating proteins (except y-globulins) by receiving
amino acids from GI and muscles
Plasma – 60-80g/L of protein – mainly in albumin, globulin and
fibrinogen
Albumin – ½ life of 16-24 days and 10-12g produced per day.
Function is to 1. Maintain colloid osmotic pressure and 2. To
transport water-insoluble substances e.g. bilirubin, hormones, fatty
acids and drugs. Hypoalbuminaemia is seen in chronic liver
disease, malnutrition, hypercatabolic states (trauma & sepsis) &
where there is excessive loss (nephritic syndrome)
Transport/carrier proteins are also formed : transferring,
caeruloplasmin
Also synthesises fibrinogen, factors 5,7,9,10 and 13, proteins C & S
and antithrombin.
Stores vitamin A, D & B12, and iron, haemosiderin and copper.
Nitrogen Excretion:
Amino acids ammonia urea
Carbohydrate Metabolism
Glucose homeostasis, by storing approx 80g of glycogen.
Lipid Metabolism
Fats are insoluble in water so transported as lipoproteins.
3. Formation of bile and bilirubin metabolism.
Hormone and Drug Inactivation – catabolises insulin, glucagon, oestrogens,
growth hormone, glucocorticoids and parathyroid hormones
Immunological Function – bacteria and other antigens are phagocytosed and
degraded by Kupffer cells.
Investigations
LFTS –
serum albumin & bilirubin
prothrombin time
Liver Biochemistry –
serum aspartate and alanine aminotransferases –show hepatocellular damage
serum alkaline phosphatise, y-glutamyl transpeptidase - cholestasis
total protein