Download White blood cells

II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
Blood composition
Blood consists of a pale yellow fluid called plasma in which are suspended
white blood cells, platelets and red cells.
Centrifuged
whole blood
Microscope drawing
of blood smear
white cells
plasma
red cells
white
cells
red cells
If blood is centrifuged the cells precipitate leaving the plasma as a supernatant.
Here is a photograph of a blood smear taken down a microscope
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
Blood composition
Can you label the arrows?
Plasma transports:
plasma
Microscope drawing
of blood smear
Carbon dioxide from the organs
to the lungs
Soluble products of digestion
from the small intestine to other
organs
Urea from the liver to the kidneys
Plasma contains a variety of dissolved solutes
such as urea, glucose, hormones.
It also contains plasma proteins that remain
in the blood all the time.
platelet
red
blood
cell
white
blood
cell
IGCSE BIOLOGY – 11.7 TRANSPORT
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
Blood composition
Microscope drawing
of blood smear
White cells:
Have a nucleus
Form part of the
body’s defence
system against
microbes
white
cells
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
Blood composition
Red cells
Have no nucleus
Microscope drawing
of blood smear
Are packed with a
red pigment called
haemoglobin
In the lungs oxygen
combines with
haemoglobin to form
oxyhaemoglobin
In other organ
oxyhaemoglobin splits
into haemoglobin +O2
red cells
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
Blood composition
Design features of red blood cells for oxygen carriage
No nucleus making
more room for
haemoglobin
Doughnut shaped
giving greater
surface area for gas
exchange
Microscope drawing
of blood smear
red cells
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
Blood composition
Platelets
Platelets are small fragments of cells
Platelets have no
nucleus
Platelets help
blood to clot at the
site of a wound
platelets
Light microscope photograph of a stained blood
sample (X3000) Platelets are stained blue
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
The immune system
White blood cells
If pathogens gain entry to the body 2 types of white cells attack them:
lymphocyte
Makes antibodies which attach to the
pathogen and help disable or destroy it
Produces antitoxins which neutralise
any toxins produced by the pathogen
phagocyte
Phagocytic - engulfs the pathogen and
digests it.
Microscope photo of a human blood smear
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
The immune system
White blood cells
– phagocytosis and antibody action
Pathogen engulfed
by white cell
Invading pathogens usually a
bacteria or viruses
engulfs and digests
pathogens by
phagocytosis
Phagocyte.
Pathogen toxin
Pathogen or toxins produced
by the pathogen
produces antibodies to
attack the pathogens or
their toxins
antibody
Lymphoctye
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
The immune system
Re-infection
Once they have produced antibodies against a particular bacterium or virus,
white memory cells can produce them quicker, and in greater quantity if
the pathogen returns, giving the person immunity against that disease
Level of
antibody
in the
blood
Memory cells: rapid
and massive
antibody production
The pathogen is
eliminated but the
damaging symptoms
of disease will have
already occurred
The pathogen is
eliminated before
disease symptoms
and dangers occur
Time
initial
infection
infection
over
new
infection
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
The immune system
Vaccination
Introducing a mild or dead form of the disease into a person causes the
production of antibodies without the symptoms of disease
Level of
antibody
in the
blood
HOW
VACCINATION
WORKS
Memory cells: rapid
and massive
antibody production
Antibodies produced
but no disease
symptoms
The pathogen is
eliminated before
disease symptoms
and dangers occur
Time
Vaccination
with mild or
dead pathogen
Infection with the real
virulent pathogen
IGCSE BIOLOGY – 11.7 TRANSPORT
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
Blood clotting
When a blood vessel is damaged,
either by a cut or other means, the
blood clots for 2 reasons:
To prevent leakage of blood
To prevent the entry of pathogens
How clotting happens:
A blood clot forming – the blood protein
fibrin (white) acts like a net at the point of
damage. It catches red blood cells and
they form a clump which blocks the
opening in the blood vessel
fibrinogen which
There is a protein called ___________
circulated in the blood. At points of damage in
blood vessels this protein is converted to
fibrin a net like protein which catches red
_______,
blood cells and forms a tangle, or clot.
IGCSE BIOLOGY – 11.7 TRANSPORT
II.7 ANIMAL TRANSPORT
THE HEART
THE IMMUNE SYSTEM
CIRCULATORY SYSTEM
THE LYMPHATIC SYSTEM
BLOOD AND BLOOD CELLS
ROUND UP
Blood clotting
White blood cells move to the clot to
kill bacteria of viruses entering through
the point of damage
white blood cell
‘puss’ a mixture of fibrin and
dead white blood cells
fibrin
trapped red blood cell
IGCSE BIOLOGY – 11.7 TRANSPORT
II.7 ANIMAL TRANSPORT
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William Harvey was born in England in 1578.
In 1628 Harvey published An Anatomical
Study of the Motion of the Heart and of the
Blood in Animals which explained how blood
was pumped from the heart throughout the
body, then returned to the heart and
recirculated. The views this book expressed
were very controversial and lost Harvey many
patients, but it became the basis for all modern
research on the heart and blood vessels.
Types of immunity
•
Natural active immunity
Immune system activation due to infection
•
Artificial active immunity (vaccination)
Immune system activation by vaccination
•
Artificial passive immunity
Injection with antibodies.
Used against potentially fatal and fast
acting diseases e.g. tetanus antitoxin
•
Natural passive immunity
Mother’s antibodies crossing the placenta e.g. measles.
Also IgA in colostrum prevents bacterial / viral growth