Download the immune system

THE IMMUNE SYSTEM
The function of the
immune system is
to fight infection
through the
production of
cells that fight off
foreign
DISEASE:
●Any change, other than
injury, that disrupts the
normal functions
of the body.
PATHOGEN
●Any disease causing agent
●Diseases
caused by
pathogens
are called
infectious
disease.
TYPES OF DISEASES:
Some are produced by
● outside agents
o Bacteria, fungus, virus
● Environmental Factors
o Cigarette smoke, toxins
● Inherited
o Hemophilia
Agents of Disease:
●VIRUS:
otiny particles that invade and replicate
within living cells.
oAttach to surface of cells and inject their
genetic material (DNA) which takes over the
cell
 Causes the common cold, influenza,
chicken pox and warts.
Bacteria
●single-celled organisms
oCause disease by
 Breaking down tissue of
infected organism for food
 Releasing toxins that harm the
body
 Tuberculosis, meningitis, botulism,
anthrax
Protists
●any organism that is not a
plant, animal or fungus
oCause numerous infectious
diseases including malaria,
dysentery and African
sleeping sickness
Worms
●Flatworms and roundworms
oIngested- infected food
oFlatworms from streams
Infection with
Loa Loa is
spread by
biting mango
flies
Fungi
Some can attack the skin
causing ringworm and athletes
foot
How diseases are spread:
●Inherited
●Vectors – organisms that
carry disease causing agents
●Sexually transmitted
The Immune System
●the body’s main defense
against pathogens
●“remembers” each type of
pathogen that enters the
body
●IMMUNITY: the body’s ability
to destroy pathogens before
Fighting Infectious Diseases:
●Nonspecific defenses: do not
discriminate between one
threat and another.
●Specific Defenses attack
particular disease causing
agents
Nonspecific Defense:
First line of defense
●THE SKIN – the body’s most
important line of defense
●Mucus, saliva, tears- contain
enzymes to break down the cell
walls of many bacteria
●Stomach acid – destroy
pathogens that make it as far as
Nonspecific Defense:
Second line of defense
●INFLAMMATORY RESPONSE
a non-specific defense reaction to
tissue damage caused by injury or
infection
oThe presence of pathogens triggers
the production of millions of white
Inflammatory response
Specific Defenses or
Immune Response:
The reaction of the
body to particular pathogens
●ANTIGEN: substance that
triggers an immune
response.
Antibodies:
●proteins that
recognize and
bind to antigens.
●carried through
the bloodstream
to attack the
pathogen causing
the infection.
T cells: ( a type of White Blood Cell)
provide defense against abnormal
cells and pathogens
●Killer T cells track down and
destroy bacteria, fungi, or foreign
tissue that contains an antigen.
●Helper T cells produce memory
cells that “remember” the
antigen if it enters the body
Killer T Cells
VACCINATIONS
●A weakened form of a
pathogen to produce
immunity
●Stimulates the immune
system to create cells that
are ready to produce
Immune System Disorders:
●ALLERGIES: an overreaction
of the immune system to an
allergen such as pollen, dust, mold
or bee stings.
oInflammatory response
oReleases histamines that
increase flow of blood and fluids to
Autoimmune Diseases:
●When the immune system
makes a mistake and
attacks the body’s own
cells.
oType 1 diabetes, multiple
sclerosis, rheumatoid arthritis
AIDS: An Immunodeficiency
Disease
●AIDS – Acquired Immune
Deficiency Syndrome.
●HIV – Human Immunodeficiency
Virus
odestroys T cells so the body
does not have the ability to fight
Transmission of HIV
●Sex with an infected person
●Shared needles with an
infected person
●Contact with body fluids of
an infected person
●Infected mother to child
Prevention of HIV
●Safe sex
●Don’t use drugs
●Protect yourself from blood
CURE for HIV
●No cure
●The virus mutates. It is drug
resistant
●Treatments extend the quality &