1. Immune System and Disease
12/12/2017 9:18 AM
Immune System and Disease
Chapter 35
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. Infectious Disease Causes: Germ Theory of Disease
Led by Louis Pasteur (French) and Robert Koch (German) bacteriologist
Infectious Disease – Occurs when microorganisms
cause physiological changes
that disrupt normal body
functions

3. Agents of Disease
Infectious diseases can be caused by viruses, bacteria, fungi, “protist” and parasites.
Pathogens – disease – causing microorganisms;
except parasites

4. Agents of Disease Viruses Characteristics Diseases Nonliving
Replicate by inserting their genetic material into a host cell and taking over many of the host cell’s function
Diseases
Common cold
Influenza
Chicken pox
Warts

5. Agents of Disease Bacteria Characteristics Disease
Break down the tissues of an infected organism for food or release toxins that interfere with normal activity in the host
Disease
Streptococcus infection (Strept Throat)
Diphtheria
Botulism
Anthrax

6. Agents of Disease Fungi Characteristics Disease
Cause infections on the surface of the skin, mouth, throat, fingernails, and toenails.
Dangerous infection may spread from lungs to other organs
Disease
Ringworm
Thrush

7. Agents of Disease “Protists” Characteristics Disease
Single-celled Eukaryotes may infect people through contaminated water and insect bites
They take nutrients from their host
Most inflict damage to cells and tissue
Disease
Malaria
African Sleeping Sickness
Intestinal Diseases

8. Agents of Disease Parasitic Worms Characteristics Diseases
Most that infect humans are wormlike
May enter through the mouth, nose, anus, or skin
Most reside in the intestinal tract where they absorb nutrients from the host
Diseases
Trichinosis
Schistosomiasis
Hook worm
Elephantiasis

9. How Diseases Spread
Pathogens often spread by the symptoms of the actual disease
Sneezing, coughing, or diarrhea
Natural selection favors the pathogens with adaptations that help them spread from host to host

10. Coughing, Sneezing, and Physical Contact
Usually bacteria or viruses that infect the nose, throat, or respiratory tract
Spread by indirect contact
Coughing and sneezing releases thousands of tiny droplets that can be inhaled by other people
Droplets can settle on objects, you touch them then touch your nose or mouth

11. Coughing, Sneezing, and Physical Contact
Pathogens like staphylococci (staph) are drug resistant and are transferred by body to body contact or by towel or sports equipment
Prevention

12. Exchange of Body Fluids
Sexual Transmitted Disease – pathogens transmitted
by sexual activity, need
direct contact from
body to body
Include:
Herpes
Gonorrhea
Syphilis
Chlamydia

13. Exchange of Body Fluids
Other pathogens need blood to blood contact often seen with IV drug user
Hepatitis
HIV can be both transmitted by both blood and sexual contact.

14. Contaminated Water or Food
Many pathogens that infect the digestive tract are spread through the water contaminated by feces from infected people or animals
Symptoms of these diseases include diarrhea
Adaptation that helps spread pathogen
Contaminated water can be consumed or spread on fruits or vegetables
Prevention is as simple as washing foods

15. Contaminated Water or Food
Bacteria can be present in seafood and uncooked meat
Cooking properly can prevent diseases caused by these pathogens

16. Zoonosis: The Animal Connection
Zoonosis – any disease that can be transmitted
from animals to humans
Mad Cow Disease
SARS (Severe Acute Respiratory Syndrome)
West Nile Virus
Lyme Disease
Ebola
Bird Flu

17. The Animal Connection
Vectors – a carrier of a pathogen that transports
the pathogen but does not get sick itself
Infection can also occur when a person is bitten by an infected animal
Consumes the meat of an infected animal
Come in close contact with an infected animal’s waste or secretions

18. Defense Against Infection
Nonspecific Infection
1st Line of Defense
Skin – widespread physical barrier
Saliva, mucus, and tears protect openings such as mouth, nose, and eyes
Lysozyme - an enzyme contained in saliva mucus
and tears
Break down bacterial cell walls
Stomach secretions destroy many swallowed pathogens

19. Defense Against Infection
2nd Line of Defense
Inflammatory Response
Infected area become red and painful or inflamed
Response begins when pathogens stimulate cells called Mast Cells
Mast Cells release chemicals known as Histamines

20. Defense Against Infection
2nd Line of Defense
Histamines
Increase blood flow and fluids to the affected area
Causes swelling in the infected area
White blood cells move in
Phagocytes – engulf and destroy bacteria
All the above causes an increase in temperature in the area

21. Defense Against Infection
2nd Line of Defense
Interferons
Proteins (produced by host cells) that inhibit synthesis of viral proteins
This is a way of “buying time” for a specific immune response

22. Defense Against Infection
2nd Line of Defense
Fever
Increased body temperature slows down or stops the growth of some pathogens
Also speeds up the immune response
Fever caused by chemicals released by immune system

23. Specific Defenses: The Immune Response
Responds to particular pathogens
Recognizing “Self”
A healthy immune system recognizes all cells and proteins that belong in the body; as self
Recognizing “Nonself”
The immune system recognizes foreign organisms and molecules as other or “nonself”.
Once recognized as “nonself” it uses cellular and chemical weapons to attack them

24. Specific Defenses: The Immune Response
Immune Response – after an encounter with
specific invader the immune
system remembers it
This enables a more rapid response if invaded by the same pathogen

25. Specific Defenses: The Immune Response
Antigens – any foreign substance that can
stimulate an immune response
Located on the outer surface of bacteria, viruses, or parasites
The immune system response to antigens by:
Increase the number of cells the either attack the invader directly
Produce antibodies
Proteins that “tag” antigens for destruction

26. Specific Defenses: The Immune Response
Lymphocytes
B Lymphocytes (B Cells)
Produced and mature in red bone marrow
T Lymphocytes (T Cells)
Produced in bone marrow but mature in thymus
Each recognizes one specific antigen
Our gene determine particular B/T Cells
When mature both types of cells travel to lymph nodes and spleen, where they encounter antigens

27. The Immune System in Action
Humoral Immunity
Activated when antibodies embedded on a few existing B cells bind to antigens on the surface of invading pathogen
When an antigen binds to an antibody carried by a B Cell, T Cells stimulate B Cells to grow and divide rapidly
B Cells of 2 types are produced:
Plasma Cells
Produce and release antibodies that are carried through the blood stream
These antibodies recognize and bind to free floating antigens or surfaces of pathogens

28. The Immune System in Action
Memory B Cells
Plasma cells die after an infection
Some B Cells that would recognize the same antigen remain alive
B Cells produce new plasma cells to battle returning pathogen
Very fast; provides long-term immunity
Immune memory is the reason vaccinations work

29. Cell-Mediated Immunity
This part of the immune system defends the body against some viruses, fungi, and single-celled pathogens
Depends on macrophages and T Cells
T Cells also helps the body from cancer cells
Macrophages consume a pathogen
A portion of antigen is out
Helper T Cells activate B Cells which activate Cytotoxic T Cells .

30. Cell-Mediated Immunity
Cytotoxic T Cells – hunts down body cells infected
with a particular antigen and kill
the cells
Suppressor T Cells – helps keep immune system in
check
Stops or slows response once infection is controlled
May also be involved in auto-immune reponse

31. Cell-Mediated Immunity
Cytotoxic T Cells make organ transplants difficult
A transplanted organ is marked as “nonself”
T Cells and proteins would damage and destroy the transplanted organ
To prevent rejection doctors search for cell markers that are identical to cell markers of the recepient

32. Fighting Infectious Disease
Acquired Immunity Vaccination - the injection of a weakened form of a pathogen or of a similar but less dangerous pathogen to produce immunity

33. Fighting Infectious Disease
Passive Immunity
Antibodies produced against a pathogen by other individuals or animals can be used to produce temporary immunity
Usually last only a short time because the immune system eventually destroys foreign antibodies
Can occur naturally:
Like from pregnant woman to fetus; across placenta or breast milk

34. Immune System Disorders
A strong immune response to harmless antigens can produce allergies, asthma, and autoimmune disease
Allergies – when allergens enter the body and trigger an
inflammatory response by causing most cells
to release histamines
If it occurs in the respiratory system it increases mucous production and causes; sneezing, watery eyes, a runny nose, etc
Antihistamines – a drug that helps response by reversing
histamine reaction.

35. Immune System Disorders
Asthma – a chronic disease in which air passages
narrow, causing wheezing, coughing,
and difficulty breathing
Can be both caused by heredity and/or environmental factors

36. Immune System Disorders
Autoimmune Disease
When the immune system attacks the body’s own cells
Type I Diabetes – antibodies attack insulin-producing
cells in the pancreas
Rheumatoid Arthritis – antibodies attack tissue
around joints
Lupus – antibodies attack organs and tissues causing
areas of chronic inflammation though out
the body

37. Immune System Disorders
Lupis
Rheumatoid Arthritis

38. Immune System Disorders
Opportunistic Disease – A disease that attacks a
person with weakened
immune system.
AIDS – Acquired Immunodeficiency Syndrome
HIV – the cause of AIDS;
Human Immunodeficiency virus

39. Immune System Disorders
HIV is deadly for two reasons:
It can hide from the defenses of the immune system
Attacks key cells within the immune system
HIV is a retrovirus
A Retrovirus carries its genetic material into the cell
The T Cell is HIV’s main target

40. Immune System Disorders
Transmission – only through infected blood,
semen, vaginal secretions, or
breast milk
Four Main ways HIV is transmitted:
Sexual intercourse
Sharing needles
Contact with infected blood products
From infected mother to her child during pregnancy, birth, or breast feeding

41. Immune System Disorders
Only no-risk behavior with HIV transmission is abstinence from sexual activity and IV drug use
No cure but a new variety of drugs makes it possible to survive