1. The Human Immune System

2. When the Castle is Under Attack The Immune System Responds!

3. What is the immune system?
The body’s defense against disease-causing organisms, malfunctioning cells, and foreign particles

4. Organs/Tissues/Cells of the Immune System
Spleen
Thymus
Bone Marrow
Tonsils
Lymph Nodes
Lymphocytes

5. Disease
Any change (other than injury) that disrupts the normal function of the body
Pathogen is a disease-causing agent
Can be bacteria, viruses, fungi, protists, worms

6. Do not write, just listen
Pathogen - Virus
Insert their RNA or DNA into host cells
Can infect plants, animals, and bacteria
Small Pox
Warts
Do not write, just listen
Bacteriophage

7. Do not write, just listen
Pathogen - Bacteria
Can break down tissues or release toxins that harm the body
clostridium botulinum
Botulism
Do not write, just listen

8. Do not write, just listen
Pathogen - Fungus
Fungi penetrate the outer layers of skin
Can infect the mouth, throat, nails
Do not write, just listen

9. How Are Diseases Spread?
Infected animals
Physical Contact
Contaminated Food and Drink

10. How does the body defend against disease?
(Innate) 1st Line of Defense - Prevent Entry
(Innate) 2nd Line of Defense - Search and destroy
(Acquired) 3rd Line of Defense - Immunity

11. Non-Specific vs Specific Defenses
Non-specific defenses do not discriminate between one threat and another
Specific defenses have “memory” of the pathogen and gives us immunity to certain diseases

12. First Line of Defense Prevent Entry

13. 1st Line of Defense (Non-specific) Skin - Fortress or Gate
In order for a pathogen to invade our body, it must first breach our skin.

14. Skin
Epidermis - outer layer of skin. Constantly sloughs off and prevents bacteria from colonizing
Sweat and oils contain anti-microbial chemicals

15. 1st Line of Defense (Non-specific) Mucus & Cilia
Mucus contains enzymes that destroy bacterial cell walls
Cilia moves mucus with trapped pathogens out of body

16. 1st Line of Defense (Non-specific) Saliva
Saliva contains chemicals that break down and destroy pathogens

17. 1st Line of Defense (Non-specific) Stomach Acid
Stomach Acid breaks down swallowed pathogens
The stomach is lined with a special mucus to prevent damage

18. Stop Here

19. Second Line of Defense Search and Destroy

20. 2nd Line of Defense (Non-specific) WBC - Phagocyte/Macrophage “The Guards”
These white blood cells surround and engulf germs that have recently entered the body.
Phagein - to eat or devour

21. Virus Attack!
Viruses turn cells into virus-making factories. The cell will eventually burst and release thousands of viruses that will infect new cells.
Cell before viral infection Cell after viral infection

22. How do cells defend against viruses?
Interferon!

23. 2nd Line of Defense (Non-specific) Interferon
Virus-infected cells release interferon when an invasion occurs
Interferon is a chemical that interferes with viral replication

24. What happens to already infected cells?
Fever Inflammatory Response T Cells

25. 2nd Line of Defense (Non-specific) Fever
Increased body temp leads to increased heart rate. More white blood cells get to site of infection
Pathogens can only survive in a narrow temperature range

26. 2nd Line of Defense (Non-specific) Inflammatory Response
Capillaries dilate to increase blood flow, WBC move to infected area
Redness, swelling and pain
Increased temperature

27. 2nd Line of Defense (Non-specific) Killer T-Cells
Recognize and attack infected cells and cancer cells
Quickly kill infected cells and search for more cells to kill

28. Stop Here

29. Third Line of Defense Immune Response (Specific Defense)

30. Immune Response (Specific Defense)
A series of specific defenses that attack a particular disease-causing agent is called an Immune Response