Download Chapter 24

THIRD EDITION
HUMAN PHYSIOLOGY
AN INTEGRATED APPROACH
Dee Unglaub Silverthorn, Ph.D.
Chapter 24
The Immune System
PowerPoint® Lecture Slide Presentation by
Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Pathogenicity of microbes
• Pathogens are microbes
that can cause disease.
• Toxins are small organic
molecules or pieces of
protein or bacterial cell
wall that are released
when bacteria die.
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How do pathogens get in? Adhesion Factors
• Adhesion factors allow a pathogen to bind to
certain cells.
• Viruses have spikes that bind to host cell
surfaces.
• Invasive mechanisms determine the extent of a
disease in the body.
• Localized vs. Systemic.
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Epidemiology
• The study of the factors that influence
transmission of diseases in human populations.
• Infectious diseases; illnesses caused by
pathogens, or their products.
• Highly transmissible pathogens (virus,
bacterial) are contagious.
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Transmission of Diseases
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Viral Diseases
• Influenza (the flu)- fever,
chills, vomiting, cold
symptoms.
• Influenza or "flu" is an
infection of the
respiratory tract that can
affect millions of people
every year. It is highly
contagious
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Body Defenses: Overview
• Physical barriers: skin & epithelial linings & cilia
• Immune defenses – internal
• Innate, non-specific, immediate response
(min/hrs)
• Acquired – attack a specific pathogen (antigen)
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Lymphatic System:
Overview of Immune Defense Organs & Cells
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Figure 24-2 ab: Anatomy of the immune system
The Composition of Whole Blood (4-6L in an adult)
• The percentage
ranges for white
blood cells
indicate the
normal variation
seen in a count of
100 white blood
cells in a healthy
individual.
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White Blood Cells (leukocytes) (0.1% of formed elements)
• Defend the body against pathogens
• Two classes
• Granular leukocytes
• Neutrophils (polymorphonuclear leukocytes)
• Eosinophils
• Basophils
• Agranular leukocytes
• Monocytes
• Lymphocytes
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Neutrophils
• Neutrophils
• Acute inflammation
• Highly mobile phagocytes
• Containing bacteria-killing enzymes
• Multi-lobular nucleus
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More Granular Leukocytes (granulocytes)
• Eosinophils
(acidophils)
• Stain with an acidic
red eosin stain
• Attracted to foreign
compounds reacted
with antibodies
• They kill pathogens
by releasing
substances that kill
them.
• 2-lobed nucleus
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•Basophils
•Stain with a deep purple or
blue basic dye
•Migrate to damaged tissue and
release their granules
•Release histamines.
•Inflammatory response;
increase capillary permeability.
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Agranular Leukocytes (agranulocytes)
• Monocytes
• Migrate into peripheral
tissues
• Are precursors to
macrophages.
• Highly mobile
phagocytic cells
• Oval, kidney-bean
shaped nucleus
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Agranular Leukocytes (agranulocytes)
• Lymphocytes (specific immunity)
• Primary cell of the lymphatic
system
• T-cells attack foreign cells
directly
• B-cells produce antibodies
that bind foreign particles
• NK cells; immunological
surveyors. Always remain
in circulation. They don’t
take up residence in
tissues.
• Large round, purple staining
nucleus.
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The immune response. Two types
• INNATE IMMUNITY:
NON-SPECIFIC
• ACQUIRED IMMUNITY:
SPECIFIC
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Innate Immunity: Phagocytosis & Inflammation
• Phagocytosis: Just eat it.
• THE PHAGOCYTES
• macrophages,
neutrophils, NK cells
• Engulf and digest
recognized "foreign" cells
– molecules
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Our immune system tags the foreign particles
• Opsonins- are the tagging proteins that make
unrecognizable particles into “food” for
phagocytes.
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Innate Immunity: Phagocytosis & Inflammation
Figure 24-6: Phagocytosis
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Inflammatory Response: hallmark fo the innate
immune pathway
• 1. acute phase
• attract immune cells to the infection site; neutrophils
• basophils to produce histamine to flush out the area;edema
swollen redness.
• 2. produce a physical barrier to retard spread of infection.
• 3. promote tissue repair post-infection; not an immune function.
• Histamines: from mast cells  swelling, edema, b. v . dilation
• Interleukins:
• Secreted by macrophages
• Stimulate liver production of acute phase proteins (opsonins)
• Alter the blood endothelium to ease the passage of WBCs.
• Bradykinin: stimulates pain & swelling to draw attention to the wound
• Membrane attack complex proteins (25 complement proteins). . .
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Inflammatory Response: Cytokines Signal Initiation
Figure 24-8: Membrane attack complex
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Some complement proteins are “warning proteins”
• Interferon is one such warning protein. Virusinfected cells produce this protein which in
turn binds to receptors of noninfected cells
causing them to prepare for possible attack.
Virus infected cell
interferon
Watch
Out
guys
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Acquired Immunity: Lymphocytes
B cell and T cells
lymphopoiesis
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Lymphocytes
• Cytotoxic T cells
• Attack foreign cells or bodies infected with
viruses
• Cell-mediated immunity
• Regulatory T cells
• Helper or suppressor T cells
• Regulate and coordinate immune response
• Memory T cells
• Remain “on reserve”
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Lymphocytes
Antibody-mediated immunity
• B cells
• Plasma cells produce antibodies
• React to specific antigens
• Immunoglobins
• Antibody mediated immunity
• Memory B cells
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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Acquired Immunity: Antigen-Specific Responses
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Figure 24-13: Functions of antibodies
T Lymphocytes: One more detail. . .
• Major histocompatability complex (MHC)
• These incorporate antigen gragments and
present them to the T cells; they come in two
flavors:
• MHC class I
• MHC class II
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Non-self proteins
Antigen
Being
Presented
To the
T-cell.
HLA antigens
(MHC proteins)
Self-proteins.
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T Lymphocytes: Cell Mediated Immunity
Figure 24-16: T lymphocytes and NK cells
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Blood Types:
Like Antibodies & antigens will agglutinate
• Antigens on RBCs (A, B, AB or none = O)
• Antibodies in plasma (anti A, anti B, anti AB)
• Rh antigens & antibodies
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Blood typing depends on RBC antigens
• Presence or absence of specific surface antigens on
RBC cell membranes. An antigen is a genetically
determined glycoprotein. There are 3 antigens we
type for:
• A, B, and D (Rh)
• Antibodies attack “foreign” surface antigens. YOUR
antibodies NEVER attack your antigens.
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Blood Type
• A person with:
• Type A blood
• Surface antigen A, anti-B antibodies
• Type B blood
• Surface antigen B, anti-A antibodies
• Type AB blood
• Surface antigens A and B, no A or B antibodies
• Type O blood
• No surface antigens, both anti-A, anti-B antibodies
• Rh positive has the Rh surface antigens and no Rh
antibodies
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Figure 20.4 Blood Typing
• The blood type depends on the presence of
agglutinogens on RBC surfaces.
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Blood Typing
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INDUCED IMMUNITY
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INDUCED IMMUNITY
• ACTIVE IMMUNITY- inject a bit of the antigen
(vaccine) and let the body’s immune system make
antibodies against it.
• IMMUNIZATION
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“BOOSTER”
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• Active Immunity.
Dependent upon the presence of memory B and
T cells capable of responding to lower antigen
doses.
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