Transcript the immune system

THE IMMUNE SYSTEM
Immune System
• Protects you against foreign
invaders…PATHOGENS
(disease-causing organisms)
• Viruses…Bacteria…Protists…
Fungi
Antigens – foreign protein
• Lymphatic system:
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Bone marrow
Lymphocytes
Spleen
Thymus
IMMUNITY
Virus
Protein coat (capsid) surrounds
core of nucleic acid (DNA or
RNA)
Needs a host cell to reproduce
(invades)
Specific for a particular host
Able to mutate
HIV, Flu, cold, Ebola, measles,
smallpox, polio, Rabies
Don’t grow…develop…
need energy…respond
Bacteria
Many bacteria are beneficial…but
some do cause disease & make us
sick
Streptococcus (strep throat)
Tuberculosis
Diptheria
Salmonella
Botulism
MRSA (staph)
tetanus
Parasites: Protists & Fungi
Caused by PROTISTS…
• Amoebic dysentery
• Malaria
• African Sleeping Sickness
Caused by FUNGI…
• Ringworm
• Candidiasis
TYPES OF IMMUNITY
INNATE/NONSPECIFIC IMMUNE
RESPONSE
• Not specific to any particular
pathogen
• Reacts within hours of pathogen
entering the body
• First line of defense: your skin
• Mucus membranes
• Chemicals
• phagocytosis
ADAPTIVE/SPECIFIC IMMUNE
RESPONSE
• Antigen specific
• Antigen must first be detected &
recognized
• Creates an army of immune cells
specifically designed to attack the
antigen
• Antigen is “remembered”
• Antibodies – proteins your body
makes to defend itself against
antigens
Adaptive Immune System
antigen-antibody response
B cells: make antibodies
T cells: Help B cells make
antibodies; Kill infected cells
Lymphatic System
• Bone Marrow…produce WBCs
• Spleen…store WBCs
• Thymus…T cells: destroy infected
or cancerous cells
• Lymph nodes…produce
lymphocytes & leukocytes
• Lymphocytes…T cells & B cells
• Leukocytes: WBCs
Immunity can be…
Active
Your body makes the antibodies
Ex: having the disease, getting a
vaccination
Antibodies remember the
disease antigen so it’s ready
to destroy next time it enters
your body
Passive
You get the antibodies from
another source
Ex: from mother thru the placenta
or mothers milk, from a shot
(rabies shot)
Protecting Ourselves
Against Viruses
• Vaccinations:
• Weakened form of virus injected in body to
stimulate immune response to make
antibodies against virus
• So next time you get virus; already have
antibodies to destroy virus
• However, so many flu & cold viruses…and
they mutate so often…can’t get vaccinated
against all
Against Bacteria
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Antibiotics:
Discovered in early 1900’s
Kill bacteria
Decades of exposure has
produced resistant
bacteria
• Antibiotics don’t work on
them anymore
• NATURAL SELECTION