1. THE IMMUNE SYSTEM AND MECHANISMS OF DEFENSE
Chapter 13

2. Pathogens can cause damage to our bodies by
releasing harmful enzymes or toxins.
causing our cells to rupture.
using up our body’s resources.
d. All the above

3. Types of Pathogens

4. Bacteria Characteristics: Prokaryotic Single celled
Use of variety of resources for growth and reproduction

5. Bacterial Infections:
Pneumonia
tonsillitis
tuberculosis
botulism
syphilis
Lyme disease

6. Viruses
Characteristics
Extremely small
Non-Living?

7. Viral Infections
AIDS
hepatitis
rabies
colds
warts
chicken pox

8. Determination of Health Risk
Transmissibility:
how easily passed from person to person
Mode of transmission:
respiratory, fecal–oral, body fluids
Virulence:
how much damage caused by infection

9. Lymphatic System: Functions
Maintenance of blood volume in cardiovascular system
Transport of fats and fat-soluble material from digestive system
Filtration of foreign material to defend against infection

10. Lymphatic System: Components
protein-containing fluid transported by lymphatic vessels
Lymph nodes
cleanse lymph by filtering out material
Spleen
cleanses blood, removes dying red blood cells, helps fight infection

11. Thymus
secretes thymosin and thymopoietin to cause T lymphocytes to mature
Tonsils
protect throat

12. SECTION ASSIGNMENT  Due at the end of class
USE THE TEXTBOOK

13. Physical and Chemical Barriers

14. First Line of Defense Provides physical and chemical barriers:
Skin: characteristics of barrier
Structure: dead layer, inhospitable to microorganisms
Constant replacement: many adhering microorganisms removed
pH = 5–6: too acidic for many microorganisms

15. First Line of Defense Other: tears saliva earwax digestive acids mucus
vomiting

16. Nonspecific Defenses: Second Line

17. Nonspecific Defenses: Second Line
Phagocytosis
by neutrophils, macrophages, eosinophils
Inflammatory response
Signs: redness, warmth, swelling, pain

18. Inflammatory Response Process:
tissue damage leads to release of histamine,
blood vessels dilate,
complement marks bacteria,
phagocytic cells arrive and remove invading microorganisms

19. The Inflammatory Response
Figure 9.7

20. Lines of Defense: Second Line
Natural killer cells: lymphocytes
Complement system: group of plasma proteins
Interferons: interfere with virus spread
Fever: increases host cell defenses and metabolic activity

21. Cells & Proteins Involved in Specific Defenses

22. Specific Defense Mechanism: Third Line
Immune response
Antigens: major histocompatibility complex (MHC) proteins
B cells: antibody-mediated immunity, action by antibodies:
Classes of antibodies
Examples – IgG, IgM, IgA, IgE

23. Line of Defense: Third Line
T cells
cell-mediated immunity, action by cells
Helper T cells
stimulate other immune cells
Cytotoxic T cells
kill abnormal and foreign cells
Memory T cells
reactivate on re-exposure
Suppressor T cells
suppress other immune cells

24. The Basis of Immunity
Due to memory cells

25. Immune Memory Creates Immunity: Primary Immune Response
Process:
recognition of antigen, production and proliferation of B and T cells
Characteristics:
lag time of 3–6 days for antibody production, peak at 10–12 days

26. Immune Memory Creates Immunity: Secondary Immune Response
Process
recognition of antigen, production and proliferation of T cells and plasma cells
Characteristics
lag time in a few hours, peak in days

27. Medical Assistance in the War Against Pathogens
Active immunization
effective against viruses
Antibiotics
effective only against bacteria, resistance a problem

28. Inappropriate Immune Responses
Allergies
hypersensitivity reaction, excessive inflammatory response mediated by IgE
Types of allergic responses
Localized: affect only the area exposed
Systemic: affect several organ systems

29. Anaphylactic shock: severe systemic allergic reaction
Symptoms:
difficulty breathing
severe stomach cramps
swelling throughout the body
circulatory collapse
drop in blood pressure

30. Inappropriate Immune Responses: Autoimmune Disorders
Defective recognition of “self”
Lupus erythymatosis (LE or lupus):
inflamed connective tissue
Rheumatoid arthritis:
inflamed synovial membrane