1. Disease and the Immune System

2. Disease: Any change to normal body function except for injury.
Some diseases are genetic
PKU
Sickle-cell anemia
Type I Diabetes
_________________________
Materials in the environment often cause disease.
Cigarette smoke
Chemicals
Toxins

3. Other causes of disease
Pathogens: The causes of infectious diseases.
Bacteria, virus, protozoa, fungi, and parasites
Not ALL species of these organisms are pathogens.
Reservoir: Source of the pathogen in the environment.
Animals, humans, soil, inanimate objects.
Infectious disease_________________________________________________________________________________.

4. Spread of infectious diseases
Physical contact
Touch, sexual or indirect contact
Contaminated food/water
Infected animals
Vectors

5. Vectors: Organisms that carry the disease
Most common are ticks and mosquitoes through biting.
Flies can act as a vector by landing in disease and then on humans.

6. Symptoms of disease
When a pathogen invades it infects cells of the body.
These infected cells are often ruptured, or killed.
Other times toxins are produced that affect specific organs or systems.
Sometimes the symptoms felt are the body’s immune system fighting back.

7. Disease Patterns
As an outbreak of a disease spreads a number of agencies are notified.
CDC and WHO monitor disease patterns
Endemic disease
Epidemic
Pandemic

8. Methods of fighting disease
The Immune System – natural defense
Antibiotics are a method of combating infectious disease.
Attack microorganism’s cells or cellular process
Do not harm human cells

9. Immune System: 2 components. Specific and Nonspecific Immunity
Nonspecific Immunity is the first line of defense.
Provide a general defense against al pathogens
Slows progression of disease while specific immunity kicks in
Barriers: Prevent pathogens from entering the body
Skin – physical barrier
Layers of dead skin cells and waxes coating the living cells beneath.
Chemical – attacks incoming pathogens
Saliva, tears, mucus contain enzymes (lysozyme) that attacks and destroys bacteria cell walls.
HCl in the stomach kills bacteria if they enter

10. Nonspecific Response
Cellular defense – A type of White Blood Cells (WBC) called macrophages undergo phagocytosis.
Interferon – cells infected with a virus secrete a protein called interferon which stimulates neighbor cells to make antiviral proteins.

11. Inflammatory response
Damaged tissue and invading cells release proteins which allow for WBCs to get to the area.

12. Specific Immunity – Involves Lymphatic System
The lymphatic system filters blood and lymph and destroys microorganisms.
Destroys fat
Lymph is a clear fluid that bathes body cells and is collected by lymph vessels.

13. Lymphatic Organs
Each of the following organs is made of lymph tissues, lymphocytes, and connective tissue.
Lymph nodes
Tonsils
Spleen
Thymus

14. Components to the Immune System
Macrophages – phagocytosis
Helper T Cells – activate B and cytotoxic T cells
B Cells – Create antibodies and memory cells
Cytotoxic T Cells – direct attack on invading pathogens

15. Specific Immunity – B Cell Response
B Lymphocytes are found in all lymph tissue. They have the role of being antibody factories.
Antibodies are proteins made by B lymphocytes that target specific foreign antigens.
Antigens are anything foreign to the body that cause immune responses.

16. B Cell Response
Macrophages present antigens on their surface. This antigen is called a processed antigen.
The macrophage then binds to a helper T Cell (Another type of lymphocyte).
The helper T Cell is now considered “activated”.

17. B Cell Response
The activated helper T Cell go on to activate B cells and cytotoxic T cells.
When activated B Cells divide and mature into plasma cells and are given instructions to make specific antibodies to the antigen found.
The activated B cell creates the active plasma cell and memory cells.

18. B Cell Response
The antibodies attach to the foreign antigen and cause clumping, making it easy for macrophages to destroy them

19. T Cell Response The helper T cells also activate cytotoxic T cells.
1. These cytotoxic T cells release cytokines which signals the immune system to activate.
2. The cytotoxic T cells also directly attack pathogens and destroy them.

20. Types of Immunity
Primary Response – first response to an invasion in the body.
Passive Immunity – A form of temporary protection against a pathogen. The antibodies are made by other humans/animals and injected into the infected patient.
Done for people exposed to rabies, tetanus, hepatitis and venoms.
Also done by pregnant mothers, passing antibodies through the placenta to the developing fetus.

21. Types of Immunity
Active Immunity – The memory cells produced by B cells maturing are involved in long-term memory of pathogens.
This type of immunity is a result from a previous infection OR immunization.
Immunization is when a weakened/dead strain of a pathogen is injected into the body so that a first response can occur

22. Booster Shots After the first injection antibodies are made.
A second injection is made to further boost the amount of antibodies/memory cells made.

23. Immune System Failure
Certain disease attack the immune system directly.
HIV is a virus that infects helper T cells.
These T cells become HIV producing factories.
As a result the immune system cannot fight other diseases over time.