blood consists of a pale yellow fluid called plasma in which are suspended white blood cells,...

Blood consists of a pale yellow fluid called plasma in which are suspended white blood cells, platelets and red cells.

If blood is centrifuged the cells precipitate leaving the plasma as a supernatant.

Microscope drawing of blood smear

Centrifuged whole blood

plasma

white cells

red cells

Here is a photograph of a blood smear taken down a microscope

red cellswhite cells

II.7 ANIMAL TRANSPORTBlood composition

CIRCULATORY SYSTEM

THE IMMUNE SYSTEMTHE HEART

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THE LYMPHATIC SYSTEM

BLOOD AND BLOOD CELLS


Plasma transports:

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.


plasma

red blood cell

whiteblood cell

platelet

Can you label the arrows?

CIRCULATORY SYSTEM


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White cells:Have a nucleus

Form part of the body’s defence system against microbes

white cells

II.7 ANIMAL TRANSPORTIGCSE BIOLOGY – 11.7 TRANSPORT

Blood composition

CIRCULATORY SYSTEM


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Red cellsHave no nucleus

Are packed with a red pigment called haemoglobin

In the lungs oxygen combines with haemoglobin to form oxyhaemoglobin red cells

In other organ oxyhaemoglobin splits into haemoglobin +O2


CIRCULATORY SYSTEM


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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

red cells


CIRCULATORY SYSTEM


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Light microscope photograph of a stained blood sample (X3000) Platelets are stained blue

PlateletsPlatelets are small fragments of cells

Platelets have no nucleus

Platelets help blood to clot at the site of a wound

platelets


CIRCULATORY SYSTEM


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White blood cellsIf pathogens gain entry to the body 2 types of white cells attack them:

phagocyte

lymphocyte Makes antibodies which attach to the pathogen and help disable or destroy it

Produces antitoxins which neutralise any toxins produced by the pathogen

Phagocytic - engulfs the pathogen and digests it.

Microscope photo of a human blood smear

II.7 ANIMAL TRANSPORTThe immune system

CIRCULATORY SYSTEM


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White blood cells

Lymphoctye

Pathogen or toxins produced by the pathogen

Invading pathogens usually a bacteria or viruses Phagocyte.

engulfs and digests pathogens by phagocytosis

produces antibodies to attack the pathogens or

their toxins

antibody

Pathogen toxin

Pathogen engulfed by white cell

– phagocytosis and antibody action


CIRCULATORY SYSTEM


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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

Re-infection

Level of antibody

in the blood

Time

initial infection

infection over

new infection

The pathogen is eliminated but the damaging symptoms of disease will have already occurred

The pathogen is eliminated before disease symptoms and dangers occur

Memory cells: rapid and massive

antibody production


CIRCULATORY SYSTEM


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Introducing a mild or dead form of the disease into a person causes the production of antibodies without the symptoms of disease

Vaccination

Level of antibody

in the blood

Time

Vaccination with mild or dead pathogen

Infection with the real virulent pathogen

Antibodies produced but no disease symptoms

The pathogen is eliminated before disease symptoms and dangers occur

Memory cells: rapid and massive

antibody production

HOW VACCINATION WORKS


CIRCULATORY SYSTEM


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Blood clotting

CIRCULATORY SYSTEM


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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

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

How clotting happens:

There is a protein called ___________ which circulated in the blood. At points of damage in blood vessels this protein is converted to _______, a net like protein which catches red blood cells and forms a tangle, or clot.

fibrinogen

fibrin


Blood clotting

CIRCULATORY SYSTEM


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white blood cell

fibrin

trapped red blood cell

‘puss’ a mixture of fibrin and dead white blood cells

White blood cells move to the clot to kill bacteria of viruses entering through the point of damage

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.


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Types of immunity

• Natural active immunity

• Artificial active immunity (vaccination)

• Artificial passive immunity

• Natural passive immunity

Immune system activation due to infection

Immune system activation by vaccination

Injection with antibodies. Used against potentially fatal and fast acting diseases e.g. tetanus antitoxin

Mother’s antibodies crossing the placenta e.g. measles. Also IgA in colostrum prevents bacterial / viral growth

blood consists of a pale yellow fluid called plasma in which are suspended white blood cells,...

Documents

lymphatic system blood

human blood smear

oxyhaemoglobin red cells

microbes white cells

types of white cells

gas exchange red cells

bodys defence system

heart round