PowerPoint® to accompany
Medical Assisting
Chapter 29
Second Edition
Ramutkowski Booth Pugh Thompson Whicker
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1
The Immune System
Objectives
291 Spell, define, and correctly use the Key Terms in
this chapter.
292 Define the terms infection, pathogen, and
antigen.
293 List and describe the nonspecific body defense
mechanisms.
294 Explain the signs and causes of inflammation.
295 Explain what is meant by specific body
defenses.
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The Immune System
Objectives (cont.)
296
Define B cells and T cells and describe their
locations and functions.
297 Explain the importance of MHC proteins.
298 List the different types of T cells and describe
their functions.
299 List the different types of antibodies and tell
how they differ.
2910 Explain how antibodies fight infection.
2911 Define complement and give its functions.
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The Immune System
Objectives (cont.)
2912 Explain the difference between the primary
immune response and secondary immune
response.
2913 Describe the function of a vaccine.
2914 Explain the four different types of acquired
immunities.
2915 Describe how allergies develop.
4
The Immune System
Objectives (cont.)
2916
2917
2918
2919
2920
2921
Explain how the AIDS virus affects the
immune system.
Identify the ways a person acquires AIDS.
Define cancer and carcinogen.
Explain how cancers are classified.
Describe how cancers are diagnosed and
treated.
Describe the signs and symptoms of other
common immune disorders.
5
Introduction
Immune system protects the body against
Bacteria
Viruses
Fungi
Toxins
Parasites
Cancer
Click for Larger View
6
T and B Cell Activation
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Defenses Against Disease
Infection is the presence
Infection is the presence
of a pathogen in or on
of a pathogen in or on
the body
the body
Nonspecific defenses
Nonspecific defenses
mechanisms to
mechanisms to
protect us against
protect us against
pathogens in general
pathogens in general
Nonspecific Defenses
Species Resistance
Mechanical Barriers
Chemical Barriers
Fever
Inflammation
Phagocytosis
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Specific Defenses
Against Disease
Specific defenses are
called immunities and
protect the body against
very specific pathogens
Lymphocytes and
macrophages are the
major white blood
cells involved in
specific defenses.
Antibodies and
complement are the
major proteins
involved in specific
defenses
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Inflammation
Causes:
Causes:
Injured or
Injured or
infected with a
infected with a
pathogen,
pathogen,
inflammation
inflammation
can result
can result
Signs:
Signs:
Redness
Redness
Heat
Heat
Swelling
Swelling
Pain
Pain
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Apply Your Knowledge
Your 18yearold patient states that he
thinks his right big toe is inflamed.
What symptoms would you expect to
see?
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Apply Your Knowledge Answer
Your 18yearold patient states that he
thinks his right big toe is inflamed.
What symptoms would you expect to
see?
Redness, heat, swelling, and pain
12
B Cells & T Cells
Two major types of lymphocytes
B Cells and T Cells
Recognize antigens in the body
BBcells
cells
Respond
Respond to
to antigens
antigens
by
bybecoming
becomingplasma
plasma
cell
cell--make
make antibodies
antibodies
against
againstthe
thespecific
specific
antigen
antigen
TT Cells
Cells
Cell-mediated
Cell-mediated
bind
bind to
to antigens
antigenson
on
cells
cellsand
and attack
attack
them
them directly
directly
13
Major Histocompatibility
Complex (MHC)
Before a T cell can respond to an antigen, it
Before a T cell can respond to an antigen, it
must be activated
must be activated
T cell activation begins when a macrophage
T cell activation begins when a macrophage
ingests and digests a pathogen that has antigens
ingests and digests a pathogen that has antigens
Macrophage then takes some of the antigens
Macrophage then takes some of the antigens
from the pathogen and puts them on its cell
from the pathogen and puts them on its cell
membrane next to a large protein complex
membrane next to a large protein complex
(MHC)
(MHC)
T cells cannot be activated without macrophages
T cells cannot be activated without macrophages
and MHC proteins
and MHC proteins
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T Cells
Helper T cells
Helper T cells
increase antibody formation, memory cell
increase antibody formation, memory cell
formation, B cell formation, and phagocytosis
formation, B cell formation, and phagocytosis
Memory T cells
Memory T cells
memory cells “remember” the pathogen that
memory cells “remember” the pathogen that
activated the original T cell
activated the original T cell
person is later exposed to the same pathogen,
person is later exposed to the same pathogen,
memory cells trigger an immune response that is
memory cells trigger an immune response that is
more effective than the first immune response
more effective than the first immune response
15
Antibodies
IgG recognizes bacteria, viruses, and toxins. It can
also activate complement.
IgA found in secretions of the body such as breast
milk, sweat, tears, saliva, and mucusprevents
pathogens from entering the body.
IgM very large primarily binds to antigens on
food, bacteria, or incompatible blood cells activates
complement.
IgE found wherever IgA is located involved in
triggering allergic reactions.
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Antibodies Fight Infection
Allow phagocytes to recognize and destroy
Allow phagocytes to recognize and destroy
antigens.
antigens.
Cause antigens to clump together which causes
Cause antigens to clump together which causes
them to be destroyed by macrophages
them to be destroyed by macrophages
Cover the toxic portions of antigens to make them
Cover the toxic portions of antigens to make them
harmless.
harmless.
Activate complement
Activate complement
Group of proteins in serum that attack
Group of proteins in serum that attack
Pathogens by forming holes in them.
Pathogens by forming holes in them.
Attract macrophages to pathogens and can stimulate
Attract macrophages to pathogens and can stimulate
inflammation.
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inflammation.
Immune Response
Primary immune response occurs the first time
a person is exposed to an antigen
slow
takes several weeks to occur
memory cells are made
Secondary immune response occurs the next
time a person is exposed to the same antigen
very quick
usually prevents a person from developing a
disease from the antigen
18
Types of Immunity
Naturally acquired active naturally
exposed to an antigen usually long
lasting
Artificially acquired activebeing
injected with a pathogen (immunizations
or vaccines)
Naturally acquired passive immunity
through his mother shortlived
Artificially acquired passive
immunity when he is injected with
antibodies shortlived
19
Apply Your Knowledge
After you have give an immunization to
a 2yearold, her mother asks you why
this will work to prevent her from
getting a disease.
20
Apply Your Knowledge Answer
After you have give an immunization to
a 2yearold, her mother asks you why
this will work to prevent her from
getting a disease.
Immunization is an artificially acquired
immunity because a person develops this
immunity by being injected with a pathogen
and then subsequently making antibodies and
memory cells against the pathogen.
21
Major Immune System
Disorders
Diseases and disorders that challenge the
immune system: (the following are the
most significant)
HIV
Infections
AIDS
Cancer
Allergies
22
Acquired Immune Deficiency
Syndrome (AIDS)
Caused by human
Caused by human
immunodeficiency
immunodeficiency
virus (HIV)
virus (HIV)
infection
infection
Most common routes of
Most common routes of
transmission are
transmission are
through sexual
through sexual
contact, blood, or
contact, blood, or
from mother to child
from mother to child
during pregnancy or
during pregnancy or
breastfeeding.
breastfeeding.
Can have infection for
Can have infection for
years before
years before
developing any
developing any
symptoms of this
symptoms of this
disease
disease
Less common routes of
transmission are through
accidental needle sticks,
artificial insemination, and
organ transplants.
23
Acquired Immune Deficiency
Syndrome (AIDS) (cont.)
AIDS virus affects
AIDS virus affects
the immune system
the immune system
Counts of CD4
Counts of CD4
cells are used to
cells are used to
diagnose the stage
diagnose the stage
of HIV infection. If
of HIV infection. If
below 200 patient
below 200 patient
has AIDS
has AIDS
CD4 cells are types
CD4 cells are types
of T cells and are
of T cells and are
important for the
important for the
functions of other
functions of other
components of the
components of the
immune system.
immune system.
24
Acquired Immune Deficiency
Syndrome (AIDS) (cont.)
HIV Testing:
HIV Testing:
The most sensitive test, and most expensive
The most sensitive test, and most expensive
is called the polymerase chain reaction (PCR)
is called the polymerase chain reaction (PCR)
Determines the number of HIV particles in
Determines the number of HIV particles in
a sample of blood.
a sample of blood.
Useful in early diagnosis of HIV
Useful in early diagnosis of HIV
25