1. Immune System and Disease
Chapter 35

2. What are the basics?
Homeostasis is the ability of an organism to maintain a stable internal environment.
Diseases can disrupt this stability.
Your immune system is the organ system that protects your body from disease.
Your body has three different lines of defense against pathogens, or disease causing agents.
To the Teacher: Take time to explain the importance of the circulatory system to the immune system. Ask students why they think the immune system could not function properly without the assistance of the circulatory system? If a pathogen does get into the body, the circulatory system helps fight the infection by transporting the immune system’s specialized cells to the source of infection

3. Infectious Diseases
Occurs when pathogens cause a physiological changes that disrupt normal body functions
Pathogens are disease-causing agents
Infectious diseases can be caused by:
Viruses (non-living)
Bacteria
Fungi
Protists
Parasites

4. How do diseases spread ? Coughing, Sneezing, Physical Contact
Mostly infect the nose, throat and respiratory tract
Exchange of body fluids
Most sexually transmitted disease
Contaminated water/food
Affect the digestive tract
Diarrhea is one common symptom
Infected animals
Mad cow disease, SARS, West Nile virus, bird flu, etc

5. What are the two types of immune defense?
The immune system includes two general categories of defense mechanisms against infection.
Nonspecific defenses guard against infections by keeping most things out of the body.
Specific defenses track down harmful pathogens that have managed to break through the body’s nonspecific defenses.
To the Teacher: Refer to essential question as students identify the differences between the two types of defense.

6. The Body’s Defense Systems
Non-Specific Defense
Specific Defense
INNATE Immunity
1st and 2nd lines of defense
1st defense:
Skin
Saliva, mucus, tears
2nd defense:
Inflammatory response
ACQUIRED Immunity
3rd line of defense
The body distinguishes between “self” and “foreigner”
Respond to particular pathogens

7. Question Break:
Why do you think the 1st and 2nd defense are called innate and the 3rd defense called acquired? HINT: Innate means “instinctual” or “born with” & acquired means to obtain

8. 1st Line of Defense: Barriers to Infection
To cause disease, a pathogen must invade the body.
Your body has barriers to keep this pathogens out.
Skin provides a protective barrier.
Mucous membranes line up interior surfaces that come into contact with the environment.
Pathogens that are swallowed are likely to be destroyed by your stomach acids.
Sweat and tears contains salts, acids, and enzymes that help kill pathogens in your skin and eyes.
To the Teacher: Ask students for the name of the structure in the pictures. Some students will recognize the Great Wall of China. Add a few factoids like it is over 1500 years old and it is the only man-made structure that can be seen from outer space. Ask students to explain why they think the Chinese built the wall? What organ in our body have a similar function?

9. 2nd Line of Defense: Inflammatory Response
The inflammatory response is the body’s response to tissue damage.
As soon as pathogen enters your body, damaged tissue releases chemical signal (histamines).
Blood vessels expand. What is a consequence of this?
Plasma carries macrophages that engulf and destroy pathogens during phagocytosis
If infection persists, body may increase temperature resulting in a fever. Why?
To the Teacher: Using the information on this slide or the animation linked to the image (click on the far right side of image), have students make a graphic organizer in which they summarize the stages of the inflammatory response. You may ask students to include in their organizers the cause-and-effect relationships of the inflammatory response. A sample graphic organizer is shown below:
Inflammatory response
is triggered by
damaged or infected cells
consume invading pathogens
which causes
which release
which attracts
chemical alarm signals
increased capillary permeability
which cause
white blood cells
blood vessel dilation
which
which causes
which causes
suppresses bacterial growth
which
swelling
temperature increases

10. 3rd Line of Defense: Immune Response (Acquired immunity)
The immune response attacks specific pathogens using specialized cells and proteins
Leukocytes: white blood cells (2 types):
T cells are white blood cells that attack
and kill harmful bacteria.
B cells are white blood
cells that make antibodies.
To the Teacher: Have students who have had chickenpox raise their hands. Have them keep their hands raised if they had it more than once. Ask them to explain why most, if not all, hands went down in response to the second question.

11. Signaling the problem
An antigen is any foreign substance in the body and stimulates an immune response
An antibody is a Y-shaped protein that attaches to a specific antigen,
bind to the pathogen's membrane proteins
Acts as a flag for destruction
weaken the pathogen’s
membrane
Made by B-cells

12. Immune response has 2 styles of Action
Humoral Response
Signaling response
Activates production of B-cells
Cell-Mediated Response
Destruction response
Activates T-cell response

14. The Story of Your Body’s Soldiers
An antigen of a pathogen attaches to an antibody of a B-cell
Helper T-cells activate B cells to grow and divide rapidly into
Plasma B-cells
Memory B-cells (secondary response)
Plasma B-cells release more antibodies that mark antigens for destruction

15. The Story of Your Body’s Soldiers
Helper T-cells bind to antigen and are activated to go and activate:
More helper T-cells- to activate B cells
Cytotoxic T-cells
Produce Memory T-cells (secondary Response)
Bind to infected cells containing antigen
destroy infected cell
Puncture membrane
Initiate apoptosis (cell suicide)

16. Secondary Response- Memory B and T cells
The next time the same pathogen enters the body, the immune response is much faster at fighting it because of the memory B and T cells
Memory B and T cells are already “trained” with the antibodies produced in the
primary response
Immunity: ability to resist disease
Possible because of memory B and
T cells

18. Homework
Outline chapter 35.1

19. Immune System Day 2
Fighting Infectious Diseases

20. Bellringer- Review Specific Immune Response
hill.com/sites/ /student_view0/chapter22/animati on__the_immune_response.html
Infection/Sci-Media/Animations-and-Interactives/The- immune-system
ss=CourseCombination&loadLeftId=9&loadTopicId=354

21. How do we fight infectious disease when our immune system isn’t strong enough on its own?
CASE STUDY: Smallpox and Chicken Pox
Smallpox was once found throughout the world.
Caused illness and death wherever it occurred.
Smallpox spreads easily from one person to another.
People were once vaccinated against this disease.

22. Case Study: Small Pox
The United States stopped giving the smallpox vaccine in 1972.
In 1980, the World Health Organization (WHO) recommended that all countries stop vaccinating for smallpox.
The vaccine is no longer given to the general public because the virus has been wiped out. Or has it?

23. The last naturally occurring case of smallpox was diagnosed on 26 October 1977.
In ordinary type smallpox the bumps are filled with a thick, opaque fluid and often have a depression or dimple in the center.

24. Acquired Immunity
More than 200 years ago, the English physician Edward Jenner wondered if it might be possible to produce immunity against smallpox.
Jenner knew that people who had been affected by a mild disease called cowpox developed an immunity to smallpox.

25. Acquired Immunity
Jenner took fluid from one of the sores of a cowpox patient and put the fluid into a small cut that he made on the arm of a young farm boy named Jamie Phillips.
Two months later, he injected Jamie with fluid from a smallpox infection and …
The rest is history.
Breifly discuss medical ethics?

26. Active Immunity and Vaccination
A Vaccination is the injection of a weakened or a similar but less dangerous form of a pathogen
Stimulates immune system with an antigen
Body produces memory B and T cells
Quicken and Strengthen immune response
This is an example of Active Immunity
Natural exposure to antigen
Deliberate exposure to antigen (Vaccine)

27. Vaccines Save Lives By Preventing Disease
Vaccine’s prevent the infection of a pathogen
There are vaccines for more than 20 serious human diseases
Not every disease has a vaccine
that we have discovered

28. Passive Immunity
Diseases can be prevented also by injecting antibodies produced by other animals or individuals
This gives an individual temporary immunity
Immune system eventually destroys foreign antibody
Can also occur
Naturally (through mother’s breast milk or placental transfusion)
Deliberately (injection)

29. Both can occur naturally or deliberately
See the Difference?
Active Immunity
Inject a pathogen
Long-term immunity
Strengthens immune system
Passive Immunity
Inject antibodies
Short-term immunity
Temporarily defeats pathogen
Both can occur naturally or deliberately

30. Antibiotics
Antibiotics drugs are those that can kill bacteria without harming the host
Ex: Penicillium
They have NO effect on viruses
Why? (hint- break down the word)
There are, however, antiviral drugs that can slow down viral activity
Viruses are very difficult to get rid of
Some never are able to leave your body

31. New and Re-emerging Diseases
Why are infectious diseases changing?
New Diseases coming from ongoing merging of human and animal habitats
Misuse of medications
Evolving resistance to drugs

32. Immune System Day 3
Immune System Disorders

33. Misguided Immune Response
Sometimes an strong immune response to a harmless antigen will produce
Allergies
Asthma
Autoimmune diseases
Harmless particles: pollen, dust mites, mold, pet dander, their own cells

34. Allergies Allergens: antigens that cause allergies
When an allergen enters the body, the inflammatory response is triggered
Mast cells release histamines
Symptoms: rashes, sneezing, watery eyes, runny nose
Antihistamines are drugs that relieve allergy symptoms

35. Asthma Allergic reaction in the respiratory system Triggered by:
Air passages narrow
Causing short breath, wheezing, coughing
Triggered by:
Genetic predisposition
Environmental factors
Respiratory infections
Exercise
Emotional distress
Cold/dry air
Smoke, dust, pet dander, etc

36. Autoimmune diseases
Sometimes diseases occur where the immune system fails to properly recognize “self”
Attacks the own body’s cells or compounds
Thinks they are pathogens
Examples:
Type I diabetes
Rheumatoid Arthritis
Lupus
Some treatments can alleviate symptoms and some suppress the immune response
Sadly, there are no cures

37. HIV/AIDS- Human Immunodeficiency
HIV- Human Immunodeficiency Virus
The CAUSE of AIDS
Known as a retrovirus
Attacks the Helper T-Cells
Becomes difficult for the immune response to defend against diseases and pathogens
AIDS- Acquired Immunodeficiency Syndrome
When the amount of T-cells in the body is reduced to less than 1/6 normal count

38. HIV and AIDS attacks the immune system
HIV/AIDS is not actually the killer itself directly
The disease debilitates the immune system
The immune system can no longer efficiently respond to pathogens it normally fights off
Causes opportunistic diseases- diseases that attack a person with a weakened immune system

39. Spread and Prevention Only transmitted through contact with
Infected blood
Semen
Vaginal Secretions
Breast milk
4 main ways it spreads:
Sexual intercourse
Shared needles
Blood contact
Mother-to-child (during pregnancy, birth, breast-feeding

40. Spread and Prevention No-risk behavior includes
Sexual abstinence
Intravenous drug-use abstinence
Many people do not know they have HIV/AIDS because they have not progressed far enough in the disease
This is why it is so important to KNOW a potential sexual partner
EVERYONE being tested is essential to stop the spread

41. There is NO cure. Currently there s no cure for aids
Only drugs that can help survive for some years
VERY expensive
DEADLY misconception
Just because there are treatments, some people now believe AIDS is not serious
DEAD WRONG
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