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Unformatted text preview: Lesson 5
Lesson Intro to MICROBIOLOGY
DEA 1135 The human body
working to keep
environment in a
The system that
wards off disease
is the immune
system. Types of immunity
There are two general types of immunity: natural and acquired. •Natural immunity is the immunity with which we are born. It is inherited and permanent, and it includes such first line barriers like the skin, mucous secretions and tears. •Acquired immunity is the reaction that occurs as a result of exposure to pathogen. It allows the body to create a way to recognize these pathogens again in the future. Key Elements
In Acquired Immunity
In Acquired immunity
There are 2 types of acquired immunity. Active acquired immunity is the means by which the person’s body produces antibodies in response to a pathogen. This can be done naturally, by the person’s own body, or passively, by a vaccination. Passive acquired immunity is temporary immunity transferred from one person to another. This type of immunity has an immediate effect against the pathogen but is only temporary. It’s used to give the person’s body a chance to build it’s own protection against the infection. ACQUIRED IMMUNE RESPONSE
ACQUIRED 3 CHARACTERISTICS:
1. Self recognition
3. SELF RECOGNITION
SELF Self Recognition continued:
The body has a mechanism to recognize
and differentiate between foreign invaders
and “self” components. In
In healthy, immune competent individuals,
immune responses are not produced
against “self” components.
SPECIFICITY Specificity continued:
In most instances, the body can only
recognize the repeat invader and
specifically respond to it. Immunity
Immunity to the measles virus, for
example, does not provide immunity
against the mumps virus.
Antigen Antibodies WBC Memory continued:
The initial contact with an infectious
antigen leaves an imprint of information.
The body can better and more quickly
repel a later invasion by that same
organism. We rarely suffer twice from the same virus
i.e. - measles, mumps, etc. The first
contact imprint “remembered immunity” so
that the body repels the next invasion.
that Vaccines are a synthetic or attenuated
form of antigen (i.e.- a killed virus) used to
stimulate the production of antibodies. Every
Every time that antigen invades the body,
the body remembers (from memory) and
the appropriate antibodies are produced
by the hosts white blood cells.
by Some microorganisms are recognized as foreign material by the body, and
contain chemical groups termed antigens. If an antigen bypasses the body’s other
defenses, the immune system will produce a specific response, which is directed
against that particular antigen. IMMUNOGLOBULINS
There are five types of circulating antibodies
called immunoglobulins which are present in
blood serum and secretions (such as saliva
and tears). They are classified into categories based on
their structure and protein compositions.
structure Each has its own distinct structure and
function Immunoglobulin classifications include: Immunoglobulin G
Immunoglobulin E (IgG)
(IgE) IgG is the main immunoglobulin present in the blood and represents 70-75%
of total immunoglobulin pool. In some humans, IgG crosses the placental
barrier and is responsible for defense against infection in the first few
months of a baby’s life. IgA provides localized antibody protection on mucosal surfaces. It is found
in saliva, tears, sweat, nasal fluids, fluids of the lung and colostrum, genitourinary tract and gastro-intestinal tract. It is the primary defense against
organisms attacking the exposed body surfaces. IgM is restricted to the bloodstream and is effective against microbes by
binding with complement and causing agglutination and bacteriolysis. It is
the first immunoglobulin to take part in the immune response and plays an
important part in controlling viruses and bacteria in the bloodstream
(bacteremia). IgD is a trace antibody and may be involved in stimulating and
suppressing antibody producing cells to manufacture antibodies. AUTOIMMUNITY
Autoimmunity is when an individuals immune system
goes awry. It forms antibodies to its own tissues which
destroy these tissues.
destroy Also known as an autoimmune disorder.
(i.e. Rheumatic fever – A person may get “strep” throat,
which slightly alters heart tissue. Later strep infections
can cause further heart damage. This is because the
antibodies formed against the strep will also attack the
altered heart tissue). Other autoimmune disorders include rheumatoid arthritis,
multiple sclerosis, fibromyalgia, lupus, Crohn’s disease,
HYPERSENSITIVITY Hypersensitivity occurs when the body’s immune system
fails to protect itself against foreign material. Instead, the
antibodies formed irritate certain body cells.
A hypersensitive or allergic individual is generally more
sensitive to certain allergens than most people. (A few
common examples of allergens include grass, ragweed,
pollen, foods, penicillin and other antibiotics, bee and
Such allergens stimulate antibody formation. The
antibodies bind to certain cells in the body, causing a
characteristic allergic reaction.
An even more severe and sometimes fatal
allergic reaction is called anaphylaxis or
anaphylactic shock. It is the result of an antigenanaphylactic
antibody reaction that stimulates a massive
secretion of histamine. The individual may experience breathing
problems, headache, facial swelling, falling
blood pressure, stomach cramps and vomiting.
blood The antidote is an injection of either adrenaline
or antihistamine. If not attended quickly, death
As health care professionals we should
always ask patients whether they are
sensitive to any allergens or drugs. This precaution is necessary in order to
prevent negative and sometimes fatal
allergic responses to injected drugs.
allergic In lesson 5, we have discussed the immune
system and the body’s response to
We can conclude by saying, the immune
system is both natural and acquired, as
well as, active and passive. THE END
Chapter 15 pp. 380-402
Chapter 16 pp.403-446 ...
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This note was uploaded on 08/19/2011 for the course DEA 1135 taught by Professor Guilford during the Spring '05 term at Gulf Coast Community College.
- Spring '05