Assessment Statements
 H.4.1 Outline the circulation of blood through liver tissue,
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including the hepatic artery, hepatic portal vein, sinusoids and
hepatic vein.
H.4.2 Explain the role of the liver in regulating levels of
nutrients in the blood.
H.4.3 Outline the role of the liver in the storage of nutrients,
including carbohydrate, iron, vitamin A and vitamin D.
H.4.4 State that the liver synthesizes plasma proteins and
cholesterol.
H.4.5 State that the liver has a role in detoxification.
H.4.6 Describe the process of erythrocyte and hemoglobin
breakdown in the liver, including phagocytosis, digestion of
globin and bile pigment formation.
H.4.7 Explain the liver damage caused by excessive alcohol
consumption.
The circulation of blood through
liver tissue
 the liver is a large, lobed organ
located immediately below the
diaphragm, and above and
around the stomach
 liver is supplied with blood by
the hepatic artery & hepatic
portal vein
 hepatic artery delivers
oxygenated blood from the
heart
 hepatic portal vein brings
deoxygenated blood to the liver
from the small intestine which
also contains nutrients
 liver is drained by the hepatic
vein which carries blood back
to the heart
Circulation of blood through liver tissue
 hepatic artery carries oxygenated blood to the liver
 hepatic portal vein carries deoxygenated blood to the liver from blood
from the gut (small intestine)
 blood from hepatic portal vein and hepatic artery mix & flows through
sinusoids (i.e. blood-filled channels), past lines of liver cells
 from the sinusoid, the blood then flow on to a branch of the hepatic
vein
 hepatic vein carries blood away from liver to the heart
The roles of the liver
 The liver performs more
than 500 functions, which
includes:
 regulation of nutrient
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levels in the blood;
site of syntheses of plasma
proteins & cholesterol;
detoxification of poisons;
breakdown of
hemoglobin;
storage of nutrients;
production of bile
pigments
Role of the liver in regulating
levels of nutrients in the blood
Role of the liver in the storage of
nutrients
 liver stores excess
glucose as glycogen, it
releases glucose from
glycogen as levels drop
 liver breaks down red
blood cells
(haemoglobin) and
stores iron
 liver stores fat soluble
vitamins such as vitamin
A, vitamin D, vitamin E,
vitamin K & vitamin B12
(folic acid)
 stored nutrients are
released from the liver
when needed elsewhere
in the body
Role of liver in synthesis of plasma
proteins & cholesterol
 liver is the site of synthesis of
all the blood proteins,
including globulins, albumin,
prothrombin & fibrinogen
 most of the cholesterol
required by the body on a
daily basis is manufactured in
the liver, the remainder is
taken in as part of the diet
 cholesterol synthesized in the
liver has a variety of functions
including being a component
of cell membranes
Role of liver in detoxification
 liver detoxifies harmful
substances such as: alcohol,
drugs & toxins that have
entered the blood stream by
breaking them into harmless
forms for excretion
 drugs such as the antibiotics
penicillin & erythromycin and
sulphonamides are also broken
down into harmless wastes
which are then excreted
 hormones such as thyroid
hormone, and steroid
hormones such as oestrogen,
testosterone, & aldosterone are
similarly inactivated, ready for
removal from the blood
through the kidney
Animation: Hemoglobin Breakdown in the
Liver
Process of erythrocyte & hemoglobin
breakdown in the liver
Process of erythrocyte & hemoglobin
break down in the liver
 erythrocytes (red blood cells) have a
life span of about 120 days after which
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they rupture
worn-out red blood cells are destroyed
by Kupffer cells through phagocytosis
in the reticular endothelial system
hemoglobin is split into haem groups
and globins proteins
globins proteins are hydrolyzed to
amino acids
iron is removed from haem & stored in
the liver or spleen
haem is converted to bilirubin (bile
pigments)
bilirubin (bile pigment) transferred to
bile
amino acid are deaminated into
ammonia & hydrocarbon
ammonia is converted to urea while the
hydrocarbon (carbohydrate) is respired
Liver damage caused by excessive
alcohol consumption
 fatty liver causes cirrhosis
(inflammation of the liver) from
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alcohol abuse
i.e. usually from prolonged & excessive
drinking of alcohol
products of alcohol metabolism are
toxic to cells as alcohol consumption
reduces antioxidant activity
leads to replacement of healthy liver
cells with fibrous scar tissue
this blocks blood flow through liver ,
thus loss of functional liver cells,
blocks normal metabolism of
carbohydrates, fats & proteins
may lead to decreased ability to
remove toxins (through bile) &
production of bile and blood proteins
nutritional deprivation / susceptible to
infection/hepatic viruses;
 Outline the circulation
of blood through liver
tissue.
[3]
 Explain the liver damage
caused by excessive
alcohol consumption. [5]