Transcript The Immune System Chapter 10 (10-2)

The Immune System
“Infection Protection”
How the body protects itself from disease
Chapter 10 (10-2)
Blood
Blood is a liquid tissue
with 3 functions:
1.
Transportation
2.
Regulation
3.
Protection
We have between 4-6
L of blood
Purpose of Blood
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Transport
Regulation
Protection
Purpose of Blood
Transport:
 To carry nutrients to all cells
 To carry wastes away from cells to
removal organs
 To carry hormones (chemical
messengers)
Purpose of Blood
Regulation
 To absorb heat from one part of the
body and release it in a cooler part.
 To maintain pH and water levels.
Purpose of Blood
Protection
 To defend the body against diseasecausing agents.
 To stop the body from bleeding by
clotting.
Components of Blood
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Plasma
Erythrocytes or Red Blood Cells
Leukocytes or White Blood Cells
Platelets
Components of Blood
Plasma
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Water – 90%
Dissolved Material such as: salts, glucose, amino
acids, fatty acids, vitamins, hormones, wastes
Proteins
• Albumin – regulates movement of water out of blood
• Fibrinogen – involved in clotting
• Globulins – many functions such as:
• Transport Proteins – to move substances
• Antibodies – to destroy foreign substances and fight
disease.
Red Blood Cells
Erythrocytes
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Carry oxygen and carbon dioxide
Made in the bone marrow
30 trillion in the body
Does not contain a nucleus
Contains hemoglobin – an ironcontaining protein that causes it to be
red and to carry oxygen
Red Blood Cells
Erythrocytes
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Fun Facts:
• You have 30 trillion RBCs
• They live 120 days – then get destroyed.
• New cells are formed at the rate of 2
million per second (same rate they die)
• The liver and spleen removed dead cells
and the iron is recycled.
Anemia
When you have too few RBCs or not
enough hemoglobin (low iron in diet).
• Symptoms: not enough oxygen in blood,
you get very tired.
• Treatment: Eat more iron, get shots of
vitamin B-12 for pernicious anemia.
Sickle Cell Anemia
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Genetic Disorder – when RBCs are not
formed correctly because hemoglobin is
made wrong:
• Symptoms: RBCs are sickle
in shape and get stuck in
blood vessels causing pain.
• Treatment: Transfusions help.
Sickle Cell Anemia
White Blood Cells
Leukocytes
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Colorless blood cells
Defend the body from bacteria
and viruses
Made in the bone marrow
Have a nucleus.
They can move on their own or
carried by the blood stream.
There are five different kinds of
WBCs.
Five types of
White Blood Cells
• Neutrophils – phagocytosis of small particles
• Monocytes – phagocytosis of large particles
• Eosinophils – release clot-digesting agent, combat
allergy-causing substances
• Basophils – release heparin – anti-clotting agent,
and histamine – that causes inflammation
• Lymphocytes – produce antibodies that are
involved in the immune response
White Blood Cells
Leukocytes
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Fun Facts:
• You have 60 billion white blood cells.
• They are made at a rate of 1 million per
second.
• When you have an infection they multiply
and congregate in the area of the infection
to attack the invader.
• Pus that forms contains WBCs and
bacteria.
Leukemia
A type of cancer that produces
white blood cells.
 Symptoms include very high
WBC count.
 Treatment: includes bone
marrow transplants and
medications.
Platelets
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Cell fragments involved in
blood clotting.
Form by pinching off bits
of cytoplasm from large
cells in the bone marrow.
Do not contain a nucleus.
Surrounded by a
membrane.
Platelets
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Fun Facts
• You have 1.5 trillion platelets
• They live for 7 days
• They are produced at a rate of 200 billion a
day.
Blood Clotting
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Good Clotting - helps you to stop
bleeding when you have an injury.
Bad Clotting – when you get a clot
within a blood vessel that clogs the
vessel. You can have a stroke or heart
attack from this.
The process is basically the same…
Blood Clotting
Blood Clotting Video
Blood Clotting
1.
2.
3.
4.
5.
Platelets stick to the damaged vessel and
break.
Broken platelets release thromboplastin.
Thromboplastin converts prothrombin to
thrombin.
Thrombin converts soluble fibrinogen to
insoluble fibrin.
Fibrin forms a web to stop the bleeding.
Blood Clotting
To remove clot
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The body activates the enzyme plasmin
to dissolve the clot after the skin heals.
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The body prevents internal clots by:
• Having smooth vessels – platelets don’t
get stuck and break.
• Anticoagulants (heparin) in blood prevent
clotting.
Clotting Problems
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Internal clots form when the vessels
are not smooth – caused by build-up of
material in veins and arteries.
• Symptoms: Can cause death, strokes,
heart attacks if it blocks blood flow.
• Treatment: Heparin can be injected to
dissolve the clot if done quickly.
Hemophilia
Genetic disease where a person is
missing one or more clotting factors.
• Symptoms – internal or external bleeding
without ability to clot.
• Treatment – injections of missing factors,
blood transfusions.
Blood Clotting
http://www.youtube.com/watch?v=HFNWG
Cx_Eu4&feature=player_embedded
What Causes Disease?
Viruses
and bacteria are pathogens.
Pathogens
are microorganisms that
cause disease.
Pathogens
are everywhere; in food, in
air, in water, inside your body.
How Can We Protect
Ourselves From Pathogens?
Our Immune System has
three lines of defense.
First Line of Defense
Physical Barriers
prevent entrance of
pathogens or trap them
and washes them away.
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Skin
membranes
mucus
sweat
urine
Chemical Barriers
kill or inhibit pathogen
activity.
•Stomach acid
•tears
•saliva
Second Line of Defense
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If a pathogen gets past first line of
defense, it starts an infection.
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This activates the second line of
defense to have an inflammatory
response.
Inflammatory Response
Symptoms:
Swelling, pain, warmth, redness
Cause of Symptoms:
 Cells that got damaged by infection release
chemicals.
 These chemicals cause more blood to flow to area
,which causes symptoms.
 Macrophages (large white blood cells) come to the
area to ingest bacteria.
As Inflammatory
response continues...
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Pus forms from mixture of dead cells,
white blood cells, bacteria and body
fluid.
If pathogen is a virus, damaged cells
produce interferon that protects other
cells from damage.
Third Line of Defense
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If inflammatory response is insufficient, the
immune system takes over.
The immune system creates antibodies
and other specialized cells to stop
pathogens.
Each antibody or specialized cell is made
for a specific pathogen.
The Immune Response
(The Immune System)
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Provides immunity to pathogens
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Requires that the body can distinguish between
“self” and foreign material.
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Involves production of antibodies and
specialized cells.
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Is triggered by an antigen.
Lymphocytes
Cells that recognize antigens and either
a) produce antibodies
b) kill foreign cells
Types of lymphocytes
a) B cells
b) T cells
Type of Immune
Responses
Primary Immune
Response
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The first time you are
exposed to antigen.
No antibodies for first
five days.
Over the next 10-15
days rise in antibodies.
Secondary Immune
Response
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Second exposure to
same antigen.
Within 1-2 days
high levels of antibodies
are in blood.
Type of Immune
Responses
B Cells and Antibodies
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B cells are stimulated by helper T cells when they
see a bacterial antigen.
Helper T cells only recognize antigen after it is
ingested by a phagocyte and has been displayed
on phagocyte’s membrane.
B cells then produce plasma cells and memory B
cells.
Plasma cells make antibodies.
Memory B cells divide to make more plasma cells
without needing helper T cells – secondary
response.
T Cells and Antibodies
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T cells are stimulated by helper T cells when
they see a virus-infected cell (antigen).
Helper T cells only recognize antigen after it
is ingested by a phagocyte and has been
displayed on phagocyte’s membrane.
T cells then produce killer T cells and memory
T cells.
Killer T cells seek and destroy antigen.
Memory T cells produce killer T cells without
needing helper T cells – secondary response.
Suppressor T Cells
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Shut down the killer T cells when the
infection is stopped.
Types of Immunity
Active Immunity
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Body produces its own
antibodies or killer T
cells
Results from having the
disease.
Results from use of
vaccines containing
dead or weakened
virus.
Passive Immunity
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Body receives
antibodies from a source
Results from receiving
antibodies from
mother’s milk.
Results from vaccine
containing only
antibodies
Blood Types
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Antibodies play a part in blood types,
transfusions, and transplants.
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There are four different blood types: A,
B, AB, and O.
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You are a certain blood type if your
blood contains certain antigens.
ABO Blood Types
There are two antigens: A and B
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If you have blood type A, you have A antigens and
B antibodies.
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If you have blood type B, you have B antigens, and
A antibodies.
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If you have blood type AB, you have both A and B
antigens and no antibodies.
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If you have blood type O, you have neither antigen
and both A and B antibodies.
Transfusions
A blood recipient cannot have
antibodies to the antigens he is
receiving.
Example:
If you have A blood, you cannot safely
receive B or AB blood because you
have B antibodies.
Challenge
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Which blood type can give blood to
anyone?
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Which blood type can receive blood
from anyone?
Universal Blood Donor
A person with blood type O is called the
universal donor. Why?
Answer: His blood contains no antigens
so no one will react to it.
Transplants
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Transplanted organs trigger the
recipient’s immune system to fight these
foreign cells - called rejection
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To control this effect, the immune
system is often suppressed prior to
transplant through medications.
Universal Blood
Recipient
A person with blood type AB is the
universal recipient.
Why?
Answer: His blood contains both antigens
and no antibodies, so his blood will not
react to any blood type.
AIDS
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Acquired Immune Deficiency Syndrome affects the immune system.
Caused by HIV (human immunodeficiency
virus).
Acquired by body fluid transfer.
The virus attacks helper T cells. Why is this
bad?
Answer:
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Body can’t produce antibodies or killer T
cells and can’t fight diseases.
Symptoms: swollen glands, fever,
weakness, weight loss, inability to fight
common illnesses, fungi, cancers
(Kaposi’s sarcoma).
No cure.
Immune Disorders
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Allergies – overreaction to an antigen
that is not normally harmful. It triggers
the inflammatory response – when the
body makes histamines. To reduce
symptoms – take antihistamines.
Immune Disorders
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Autoimmune Diseases – when the body
fails to recognize its own cells as self
and produces antibodies against its own
cells.
• Lupus (various organs, kidneys), Multiple
sclerosis (nerves), rheumatic fever (heart
and joint tissue)
Immune Disorders
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Cancer – body doesn’t recognize
foreign cells as foreign and lets them
multiply uncontrollably. Suppression of
immune system often results in cancer.