Liver anatomy, physiology and diseases
affecting liver
Tejaswini Arcot
Sep 16, 2022
Anatomy
• The liver is the second largest (after the skin) organ in the
human body and the largest gland (weighing an average of
1500 g).
• It lies under the diaphragm in the right upper abdomen and
midabdomen and extends to the left upper abdomen.
• The liver has the general shape of a prism or wedge, with its
base to the right and its apex to the left (see the image
below).
• It is pinkish brown in color, with a soft consistency, and is
highly vascular and easily friable.
Liver anatomy
Anatomy
• The liver is grossly divided into two parts when viewed from
above – a right and a left lobe
• The falciform ligament makes a superficial division of the liver
into a left and right lobe.
• In Couinaud system, the functional lobes are further divided
into a total of eight subsegments based on a transverse plane
through the bifurcation of the main portal vein.
Anatomy
• The caudate lobe is a separate structure that receives blood
flow from both the right- and left-sided vascular branches.
• The Couinaud classification divides the liver into eight
functionally independent liver segments.
• Each segment has its own vascular inflow, outflow and biliary
drainage.
Physiology
• Carbohydrate and protein metabolism
• The liver is thought to be responsible for up to 500 separate
functions, usually in combination with other systems and
organs. Currently, no artificial organ or device is capable of
reproducing all the functions of the liver.
• The liver stores a multitude of substances, including vitamin A
(1–2 years’ supply), vitamin D (1–4 months’ supply), vitamin
B12 (3–5 years’ supply), vitamin K, vitamin E, iron, copper,
zinc, cobalt, molybdenum, etc.
Physiology
• Haemopoiesis - The formation of blood cells is called
haemopoiesis. In embryonic stage RBC and WBC are formed
by liver. In the first trimester fetus, the liver is the main site of
red blood cell production. By the 32nd week of gestation, the
bone marrow has almost completely taken over that task.
• Liver helps in purification of blood. The Kupffer cells of liver
are phagocytic cells, helps in phagocytosis of dead blood cells
and bacteria from the blood.
• The liver is responsible for immunological effects – the
mononuclear phagocyte system of the liver contains many
immunologically active cells, acting as a ‘sieve’ for antigens
carried to it via the portal system.
Physiology
• The liver produces albumin, the most abundant protein in
blood serum. It is essential in the maintenance of oncotic
pressure, and acts as a transport for fatty acids and steroid
hormones.
• The liver synthesizes angiotensinogen, a hormone that is
responsible for raising the blood pressure when activated by
renin, an enzyme that is released when the kidney senses low
blood pressure.
• The liver produces the enzyme catalase to break down
hydrogen peroxide, a toxic oxidising agent, into water and
LFTs
• Liver function tests (LFTs or LFs), also referred to as a hepatic
panel, are groups of blood tests that provide information
about the state of a patient’s liver.
• These tests include prothrombin time (PT/INR), activated
Partial Thromboplastin Time (aPTT), albumin, bilirubin (direct
and indirect), and others. The liver transaminases aspartate
transaminase (AST or SGOT) and alanine transaminase (ALT or
SGPT) are useful biomarkers of liver injury in a patient with
some degree of intact liver function.
LFTs
• Most liver diseases cause only mild symptoms initially, but
these diseases must be detected early. Some tests are
associated with functionality (e.g., albumin), some with
cellular integrity (e.g., transaminase), and some with
conditions linked to the biliary tract (gamma-glutamyl
transferase and alkaline phosphatase).
Normal range
Hydatid cyst
• Hydatid cyst is a parasitic disease of tapeworms of the
Echinococcus type. The two main types of the disease are
cystic echinococcosis and alveolar echinococcosis.
• The disease often starts without symptoms and this may last
for years. The symptoms and signs that occur depend on the
cyst’s location and size. Alveolar disease usually begins in the
liver, but can spread to other parts of the body, such as the
lungs or brain
• The eggs are released in the stool of meat-eating animals that
are infected by the parasite. Commonly infected animals
include dogs, foxes, and wolves.
• The type of disease that occurs in human patients depends on
the type of Echinococcus causing the infection. Diagnosis is
usually by ultrasound though computer tomography (CT) or
magnetic resonance imaging (MRI) may also be used. Blood
tests looking for antibodies against the parasite may be
helpful as may biopsy.
Hydatid cyst
• Prevention of cystic disease is by treating dogs that may carry
the disease and vaccination of sheep.
• Treatment is often difficult.
• The cystic disease may be drained through the skin, followed
by medication.
• Sometimes this type of disease is just watched.
• The alveolar form often requires surgical intervention,
followed by medications. The medication used is albendazole,
which may be needed for years. The alveolar disease may
result in death.
cyst appearance
End stage liver disease
• end-stage liver disease, is the impaired liver function caused
by the formation of scar tissue known as fibrosis due to
damage caused by liver disease.
• damage causes tissue repair and subsequent formation of
scar tissue, which over time can replace normal functioning
tissue, leading to the impaired liver function of cirrhosis.
• the disease typically develops slowly over months or years.
• early symptoms may include tiredness, weakness, loss of
appetite, unexplained weight loss, nausea and vomiting, and
discomfort in the right upper quadrant of the abdomen.
cirrhosis
End stage liver disease
• as the disease worsens, symptoms may include itchiness,
swelling in the lower legs, fluid build-up in the abdomen,
jaundice, bruising easily, and the development of spider-like
blood vessels in the skin.
• the fluid build-up in the abdomen may become spontaneously
infected.
• more serious complications include hepatic encephalopathy,
bleeding from dilated veins in the esophagus, stomach, or
intestines, and liver cancer.
End stage liver disease
• Cirrhosis is most commonly caused by alcoholic liver disease,
non-alcoholic steatohepatitis (NASH – the progressive form of
non-alcoholic fatty liver disease), heroin abuse, chronic
hepatitis B, and chronic hepatitis C.
• Heavy drinking over a number of years can cause alcoholic
liver disease.
• Liver damage has also been attributed to heroin usage over an
extended period of time as well.
End stage liver disease
• NASH has a number of causes, including obesity, high blood
pressure, abnormal levels of cholesterol, type 2 diabetes, and
metabolic syndrome.
• Less common causes of cirrhosis include autoimmune
hepatitis, primary biliary cholangitis, and primary sclerosing
cholangitis that disrupts bile duct function, genetic disorders
such as Wilson’s disease and hereditary hemochromatosis,
and chronic heart failure with liver congestion.
• Diagnosis is based on blood tests, medical imaging, and liver
biopsy.