1. The Immune
System!

2. What is a system?
A group of tissues (organs) that work together to do a certain task.
Ex) digestive system, circulatory system, immune system…
Function of the immune system is to protect your body from invasion of pathogens.

3. “The War on Pathogens” Your body is always surrounded by pathogens.
Pathogen is ?.
Viruses, bacteria, fungi, etc.
Germ theory—infectious diseases are caused by microorganisms of different types.
Diseases can be passed from one person to the next are called infectious or communicable.

4. Non-Specific Defense
Your body has several defense mechanisms to keep them out…..
FIRST LINE OF NON-SPECIFIC DEFENSE
1) skin
2) sweat
3) mucous membranes
4) saliva
SECOND LINE OF NON-SPECIFIC DEFENSE
inflammatory response

5. First Line: Skin Physical barrier
Chemical barrier- secretes oil, sweat, and tears
Sheds constantly (1 million cells per hour)

6. First Line: Mucus Membranes
These line the inside of all body openings.
Nostrils, mouth, lungs, etc.
Cells of mucus membranes:
secrete mucus that traps foreign objects
lined with hairs called cilia.
Stomach also has acid

7. Second Line of Defense: Inflammatory Response
The first line of defense has been broken…
SECOND LINE OF DEFENSE ACTIVATED: damaged cells release chemical messages that trigger a series of reactions by body-histamine
1.) capillaries to swellpuffiness
2.) increases blood flow to infected area redness
3.) temperature in area rises
4.) pain
5.) phagocytes called inget rid of pathogens
***Sometimes this response is NOT enough…

8. Immune System leave room to add more here Non-specific Defense
First line:
Skin
Sweat
Mucous
Stomach acid
Second line:
Inflammatory
Response and
Phagocytes

9. What if pathogens circulate through your body?
White blood cells have to take over.
White blood cells = “soldiers” of your immune system.

10. The Immune Response Specific Defense
Body’s attack against a pathogen that made it past the “front lines.”
Results in “immunity” because your immune response creates memory cells SPECIFIC for each pathogen.
Chicken pox

11. INFLAMMATORY RESPONSE
IMMUNE RESPONSE
SPECIFIC
SECOND LINE OF
DEFENSE:
INFLAMMATORY RESPONSE
NON-SPECIFIC
FIRST LINE OF DEFENSE:
SKIN, MUCOUS, SWEAT

12. Organs of the Immune System
White blood cells are called leukocytes
Made in the thymus (T cells) and bone marrow (B cells)
Stored in tonsils, spleen, and lymph nodes.

13. “The Soldiers” White Blood Cells
Leukocytes
Macrophages
Helper T cells
Killer T cells
B cells
Suppressor T cells
Memory cells

14. How does your body know there is an invader?
All pathogens have “distinct” marker proteins that are antigens.
Antigens -anything that causes an immune response.
Your body must recognize antigens as FOREIGN (NON-SELF) in order to create an immune response.

15. Step #1 “Invader Identification” Movie
Macrophages identify pathogen as “non-self,” eat it, display the antigen, and signal for helper T cells.
Interleukin-1 signal released= fever

16. Helper T cells “signal” for the production of other leukocytes by releasing of interleukin 2.
The next type of leukocytes called to work are known as B cells and Killer T cells.

17. Step #2 “Cloning Phase”
Many helper T cells, B cells and killer T cells produced.
After B cells called up by helper T’s, they begin to produce lots of antibodies

18. What are antibodies? Millions of antibodies are made by B cells
They are like “keys” and are specific to each antigen which are like the “locks.”
Mark pathogen for death and can also prevent virus attachment to cell.

19. Step #3 “The Attack Phase”
Pathogens marked with antibodies are destroyed by macrophages.
Killer T cells destroy any infected body cell. Movie

20. Step #4 “Memory Phase”
Macrophages act as the clean up crew, eating pathogens, damaged body cells, etc.
Suppressor T cells “call off the troops”. They suppress, or weaken, the attack.
Powerful memory T and B cells are left behind to “remember” the attack and quickly recognize a pathogen if it re-enters the body.

21. Primary vs. secondary immune response
1st time in contact with pathogen.
Takes longer for attack
Secondary:
come into contact with a pathogen you’ve already encountered
memory B cells are there to produce antibodies quickly and in greater amounts.
Primary response Secondary response

22. Immune System Immune System Non-specific Defense Specific Defense=
Immune Response
Reaction to
specific antigen
First line:
Skin
Sweat
Mucous
Stomach acid
Second line:
Inflammatory
Response and
Phagocytes
Macrophage
signal
Helper T cells
B cells:
Antibodies and
Memory Cells
Killer T cells
signal

23. Active vs. Passive Immunity
Active Immunity (immune response, vaccine)
The body ACTIVELY produces its own antibodies
Passive Immunity (breast milk)
Get antibodies from mother’s milk.

24. Immune System Failure Allergies
Allergy: Immune system response against a NON-PATHOGENIC antigen.
Food, pollen, bee stings, dust mites

25. Immune System Failure Allergies
Body produces more antibodies than you need, which causes release of histamine:
blood vessel dilation
swelling
Antihistamines are in allergy medicine that reduce swelling.
Asthma
Movie

26. Immune System Failure Autoimmune disease
Immune system fails to distinguish self from non-self.
Body makes antibodies against and attacks own cells.
Examples:
MS (attack nerve cells)
Lupus (attacks organs)
Rheumatoid arthritis
(attacks joints)

27. Immune System Failure Cancer
One major job of the immune system is immunological surveillance.
Killer T cells destroy our cancerous cells.
Immune system fails to locate and remove cancerous cell, & it multiplies to form a tumor.
Malignant tumor spreads, benign does not

28. AIDS Acquired Immunodeficiency Syndrome
Sometimes the immune system collapses totally.
HIV (Human Immunodeficiency Virus) invades helper T cells
B cells and killer T cells not stimulated to work—immune system breaks down!
Body overwhelmed with pathogens

29. Immune System Immune System Non-specific Defense Specific Defense=
Immune Response
Reaction to
specific antigen
First line:
Skin
Sweat
Mucous
Stomach acid
Second line:
Inflammatory
Response and
Phagocytes
Macrophage
signal
Helper T cells
B cells:
Antibodies and
Memory Cells
HIV
Killer T cells
signal

30. Immune System Failures
Immunological
surveillance doesn’t
locate bad cells:
Cancer
Overreact:
Allergies Asthma
Immune system
shut down due to
HIV:
Immunodeficiency
(AIDS)
Can’t tell self
from non self:
Autoimmune
disease

31. Blood types Each red blood cell has protein markers
A type blood---A protein markers
A person with type A blood makes antibodies against B markers because they are foreign
The B markers are considered antigens to the person with A blood

32. Blood types

33. Blood types
Universal donor: type O because no protein markers to cause immune response.
Universal recipient: type AB because they have both A and B markers and so don’t make antibodies to either.