Download Immune System

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 WBC’s
Target specific Pathogens
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
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 ! ! !
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 WBC’s
• What are Pathogens?
Pathogens
Organisms that cause
disease
• Infectious diseases are?
Diseases that are
caused by pathogens .
• Staphyloccocus
aureus
• Magnified 20,000X
• About 1 um in size
• When you have an
infectious disease
pathogens are inside
• What type of
your body causing harm pathogen is Staph?
BACTERIA
4 TYPES OF COMMON PATHOGENS
• Can you guess what they are?
Viruses Fungi Bacteria
Protists/Parasites
1. Viruses
Flu HIV Measles
2. Fungi
Athlete’s Foot
Candida albicans
Virus
Fungus
4 TYPES OF COMMON
PATHOGENS
3. Bacteria
STAPH
Strep throat
Bacteria
4. Protists
Paramecium
Giardia
Giardia
The Immune System
• 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? Let’s
find out!!
What happens when a virus infects a cell?
What do T-cells do?
What is another job of the T- cells?
So, why do B – cells produce antibodies?
Because……
Immunity
How does a person become immunized?
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
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
Active Immunity Both
The body makes
antibodies.
Memory cells
recognize antigens
from the pathogen.
Immunity may
last for years or
a lifetime.
Can prevent
diseases
May involve
an injection
Passive Immunity
Antibodies are
given, the body
does not make
antibodies.
Immunity can be
acquired from the
mother during
pregnancy.
Immunity lasts
only a few
months.
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
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.
5. 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
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!!
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
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 doesn’t need to make
antibodies
13. Question: Why can’t scientists produce an
effective vaccine against HIV?
Answer:
Because the virus mutates or changes
and the vaccine no longer works!!!!!