Transcript Immune_System_2016_Z - Kenston Local Schools

The Human Immune System
First lines of defense
saliva
antibacterial
enzymes
skin
prevents
entry
stomach acid
low pH kills
harmful
microbes
tears
antibacterial
enzymes
mucus linings
traps dirt and
microbes
“good” gut
bacteria out
compete bad
Pathogens
• = disease causing micro-organisms
•
•
•
•
•
•
bacteria
virus
fungi
protozoa
parasites
prion
Second lines of defense
• Involves white blood
cells
• Non-specific response
– invading pathogens are
targeted by
macrophages (WBC)
• Specific response
– lymphocytes produce
chemicals called
antibodies that target
specific pathogens
Phagocytes
The Phagocytes
• Phagocytes are the “soldiers” of the
immune system
• They are responsible for, killing and
digesting invading microbes.
• The process of swallowing microbes is
known as phagocytosis.
Phagocytes
• Monocytes and macrophages
• Provide a non-specific response to
infection
Phagocytosis
 The bacteria are digested by
enzymes, and then absorbed by
the phagocyte
 During infection, hundreds of
phagocytes are needed.
 Pus is dead bacteria and
phagocytes!
White Blood Cells
Lymphocytes
Provide a specific immune response to
infectious diseases.
There are 2 types: -
T-cells
B-cells
B Cells & T Cells
B and T cells perform specialized tasks
• B cells recognize antigens and then (as
plasma cells) mass-produce specific
antibodies
• Helper T cells coordinate the attack
• Killer T cells once activated, destroy
virus-infected cells
• T cells “T” = Activated in Thymus
Antigen
• An antigen is any
substance that
creates an immune
response, from a
virus to a sliver.
• It can also be
incorrectly
identified as an
invader (allergy
response)
Bozeman: Immune System
• https://www.google.com/search?q=bozem
an+immune+system&oq=bozeman+immu
ne+system&aqs=chrome..69i57j69i60j69i6
5j69i59j69i61.3104j0j7&sourceid=chrome
&es_sm=122&ie=UTF-8
When a virus or bacteria invade the body it is engulfed by a
macrophage cell. The macrophage then signals T-cells to cause Bcells to multiply.
Macrophage
The B Cells get the message from the T-Cells, to
produce antibodies which disable the invading bacteria.
Antibody Vs Antigen
Antigen (the virus)
Immune System Can Attack Itself
This is the case of autoimmune diseases:
– multiple sclerosis
– lupus
– some forms of arthritis
– diabetes
– allergies
Allergies
• The immune
system thinks
the foreign
invader is
harmful to you
so it “reacts”
Anaphylaxis = Life Threatening Reaction
Interferon
• A small “natural”
protein that acts
against microbes –
ESPECIALLY
Viruses
• Until recently it was
thought that IFN acted
ONLY against viruses.
• Defense & Repair: DVD – Online
https://www.youtube.com/watch?v=nqmH9
padTl4&list=PL1BEC62A88CAD28C7
– (KHS Library #824)
• Neutrophils "eat" pathogens and send off distress signals.
• Monocytes are triggered to turn into pathogen-eating
macrophages.
• Eosinophils attack parasites
• Basophils contain granules filled with histamine and other
compounds related to allergies.
• The second set of cells — the lymphocytes — is slower to
react.
• As the generalized campaign goes forward, a second set of
specialized cells known as lymphocytes begins a more specific and
enduring attack. The stars of this more adaptive immunological
defense system — killer T cells, helper T cells, and B cells — work
in concert to destroy infected cells. The B cells mature into plasma
cells that generate highly specific
• antibodies capable of producing lasting immunity.
• T cells coordinate the immune system response.
• Any material that triggers this immune response is called an
antigen.