The liver is located in the upper right portion of the abdomen under the ribs. It has four lobes and performs many important functions like producing bile, filtering blood, and synthesizing proteins and clotting factors. The liver receives blood from both the hepatic artery and portal vein. It drains into the hepatic vein which empties into the inferior vena cava. The liver's main cell type is hepatocytes which are arranged in lobules and acini centered around portal triads and central veins to efficiently filter blood and perform metabolic functions.

1. The liver is found just beneath the diaphragm on the right hand side and is under the ribs so is
not normally palpable.
Horizontally the liver runs from the edge to the midline. The bottom of the liver follows the
costal margins and the top of liver is found in the fourth intercostal space.
Production and secretion of bile
Conjugates bilirubin
Synthesises the clotting factors
Synthesises albumin
Filters the blood
The liver is divided into four lobes: the left lobe, the right lobe, the caudate lobe and the
quadrate lobe.
The right and left lobes are divided by the falciform ligament. The caudate lobe is separated
by the inferior vena cava and the fissure for ligamentum venosum. The quadrate lobe is
separated by the gall bladder and the groove for ligamentum teres.
Posterior: right kidney, hepatic flexure
of the colon, duodenum, gall bladder,
inferior vena cava, oesophagus, stomach
Superior: diaphragm
Left: spleen
Inferior: gall
bladder
Right: ribs
Anterior: diaphragm,
costal margins, pleura,
lower margins of the
lungs, xiphoid process,
anterior abdominal wall

2. The caudate and quadrate lobes are anatomically part of the right lobe but functionally part of
the left lobe of the liver.
The liver has its own hilum known as the porta hepatis. It is found on the posterorinferior
surface between the caudate and quadrate lobes.
It contains:
Right hepatic duct
Left hepatic duct
Right branch of the hepatic artery
Left branch of the hepatic artery
Portal vein
Nerve fibres
Lymph nodes
The lesser omentum is attached to porta hepatis.
The liver is covered by peritoneum. All of the liver is covered by peritoneum except for the
bare area of the liver.
The liver is supplied by both the portal vein (80%) and the hepatic artery (20%). The hepatic
artery brings oxygen rich blood. The portal vein brings blood rich in the products of digestion.
The liver is drained by the hepatic vein which drains into the inferior vena cava.
Lymph produced by the liver passes into lymph node in the porta hepatis and then into the celiac
lymph nodes. The bare area of the liver drains into posterior mediastinal lymph nodes.
The liver is supplied by the hepatic branch of the anterior vagal nerve.
remnant of ductus venosum which allows blood to bypass the liver in a foetus
: remnant of the left umbilical vein

3. The liver is made up mainly of hepatocytes. They have large central prominent nuclei, abundant
mitochondria, prominent endoplasmic reticulum, active golgi apparatus and numerous
peroxisomes (features of metabolically active secreting cells). Hepatocytes are surrounded by
sinusoids.
Hepatocytes have three different types of surfaces:
Sinusoidal – permits exchange of material with the blood
Canalicular – for excretion of bile
Intercellular
The Space of Disse is the space between the sinusoidal epithelium and hepatocytes. It contains:
Kupffer cells- phagocytic cells
Ito cells- synthesise collagen
Plasma
The basement membrane of the liver is made from reticulin- type III collagen.
There are two ways of dividing up liver cells: lobules and acini. A lobule is the area drained by
one central vein. Acini are based on blood supply and are clinically more useful.
Lobules:
Portal triad
Bile duct
Portal vein
Portal artery
Central vein
Sinusoid: capillaries with fenestrated epitheilium
Caniculi: thin tubes which collect bile and drain into bile ducts

4. A portal triad consists of:
A portal artery
A portal vein
A bile duct
They are held together by loose fibrous connective tissue
Central veins drain blood into the hepatic veins.
Acini:
Zone 2
Zone 3: furthest away from the blood supply
Zone 1: closest to the blood supply