Immune System

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Immune System

• Important system that helps fight off pathogens
• What is a Pathogen?
• Microorganism that causes infection or a disease
• Bacteria Viruses Fungi
  Protists/Parasites
• Made of different types of cells each with a
• specific job including
• a. Lymphocytes
• White blood cells or WBCs
• Target specific Pathogens

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Types of Lymphocytes

• b. T - cells
• Identify Pathogens by recognizing
• their Antigens. What is their job?
• To activate B-cells
• c. B cells
• Produce chemicals called Antibodies
• d. Macrophages
• Surround pathogen and digest
• or eat it
• Also called Phagocytes

Pathogens
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Types of Lymphocytes

• What are the Two Types of T Cells?
• 1. Natural Killers Cells
• 2. Cytotoxic Cells
• Destroy pathogens after they are marked
  by
• antibodies
• Destroy cells that are infected with a
  virus
• Also recognize cancer cells and destroy
  them
• What are Memory T- Cells ?
• They remember what type of antigens on a
  pathogen
• Help immune system recognize the pathogen if
  it
• invades our body again!! AMAZING ! ! !

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ANTIGENS AND ANTIBODIES

• What are Antigens?
• Special proteins on surface of cells and
  pathogens
• They are recognized by the Immune System
• Why?
• So the White blood cells know which pathogens
  they need to destroy!!!
• What are Antibodies?
• Special proteins that recognize specific
  Antigens
• on Pathogens
• Mark the pathogens for destruction by WBCs

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Pathogens

• What are Pathogens?
• Organisms that cause disease
• Infectious diseases are?
• Diseases that are caused by pathogens .
• When you have an infectious disease pathogens are
  inside your body causing harm

• Staphyloccocus aureus
• Magnified 20,000X
• About 1 um in size
• What type of pathogen is Staph?
• BACTERIA

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4 TYPES OF COMMON PATHOGENS

• Can you guess what they are?
• Viruses Fungi Bacteria
  Protists/Parasites
• 1. Viruses
• Flu HIV Measles
  Virus
• 2. Fungi
• Athletes Foot
• Candida albicans
• 
  Fungus

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4 TYPES OF COMMON PATHOGENS

• 3. Bacteria
• STAPH
  Bacteria
• Strep throat
• 4. Protists
• Paramecium Giardia
• Giardia

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The Immune System
together to The immune system includes T cells
and B cells. The cells work fight infections.

• The immune system includes T cells and
• B cells.
• The cells work together to fight pathogens
• and help destroy Cancer cells
• How does the immune system work? Lets
• find out!!

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What happens when a virus infects a cell?What
do T-cells do?
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What is another job of the T- cells?
.
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So, why do B cells produce antibodies?Because

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ImmunityHow does
a person become immunized?How does a person
become immunized? .
ImmunityHow does a person become immunized?
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How does the Immune System work
How does the Immune System work
T- cells recognize bacterial or viral antigen.
Some T- cells attack cells infected with pathogens
Other T-cells signal B cells to produce
antibodies .
Antibodies attach to the antigens on virus or
bacteria (Lock
Key)
Antibodies help phagocytes destroy the
bacteria or virus
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Two Types of Immunity

• Active Immunity
• Immune system produces antibodies
• on its own in response to a pathogen
• Passive Immunity
• Antibodies are injected into a patient to
• help prevent a disease from a pathogen
• Vaccine
• Contains a weakened pathogen that
  stimulates production of antibodies without
  causing the actual disease, or?
• Antibodies are already in the vaccine

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Active Immunity Both Passive Immunity
The body makes antibodies.
Antibodies are given, the body does not make
antibodies.
Can prevent diseases
Memory cells recognize antigens from the pathogen.
Immunity can be acquired from the mother during
pregnancy.
May involve an injection
Immunity may last for years or a lifetime.
Immunity lasts only a few months.
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Review Questions

• 1. Question What is the function of the immune
  
• system?
• Answer Helps fight off pathogens.
• 2. Question Which 3 white blood cells or
  lymphocytes
• help destroy pathogens?
• Answer Macrophages, B cells and T cells
• 3. Question What is an antigen?
• Answer Special protein on surface of
  pathogens recognized by the
  immune system

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Review Questions

• 4. Question What is an antibody?
• Answer Special protein in the immune
  system that recognizes and
  attaches to a
• specific antigen on a
  pathogen and
• marks the pathogen for
  destruction.
• Question Explain the difference between Active
  
• and Passive Immunity?
• Answer In Active immunity the immune
• system produces the
  antibodies.
• In Passive immunity the
  antibodies
• are injected into a
  patient to destroy
• the pathogens

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Review Questions

• 6. Question Which cells of the immune system
• produce antibodies?
• Answer B cells
• 7. Question Which cells produce B cells?
• Answer T cells
• 8. Question Name the 2 types of T- cells
• Answer 1) Natural Killer cells
• 2) Cytotoxic cells
• 9. Question What are memory T - cells?
• Answer
• They remember what type of antigens a
• pathogen has
• Help immune system recognize the
• pathogen if it invades our body again!!

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• 10. Question What are the 4 main functions of T-
  cells
• Answer
• Stimulate B-cells to produce antibodies
• Destroy pathogens after they are marked
• by antibodies
• Destroy cells that are infected with a
  virus
• Also recognize cancer cells and destroy
  them
• 11. Question What are the 4 common pathogens?
• Answer
• Virus Bacteria Fungi
  Protists/parasites

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• 12. Question Name 2 ways a vaccine works!
• Answer
• 1. Contains a weakened pathogen that
  stimulates
• production of antibodies without
  causing the
• actual disease, or?
• 2. Antibodies are already in the vaccine
  to
• destroy pathogens, body doesnt need
  to make
• antibodies
• 13. Question Why cant scientists produce an
• effective vaccine against
  HIV?
• Answer Because the virus mutates or
  changes
• and the vaccine no longer
  works!!!!!