1. The Immune System
Chapter 9
Blue Book

2. First Line Defenses These work against all harmful substances.
Unbroken skin is a barrier that prevents many pathogens from entering the body.
Skin’s secretions, such as perspiration or oil can be acidic and prevent pathogens from growing.

3. More First Line Defenses
Respiratory system uses cilia and mucus to trap pathogens. Mucus also has an enzyme that weakens the walls of some pathogens.
Sneezing and coughing expel some of the trapped pathogens.

4. And even more first line defenses!
Digestive system:
Saliva – kills bacteria
Enzymes (from stomach, pancreas and liver) kill pathogens
Hydrochloride acid – kills some bacteria and stops the activity of some viruses that enter the body from food
Mucus – has a chemical that coats bacteria and prevents it from binding to the inner lining of your digestive organs.

5. Yes, even more first line defenses!
Circulatory system: White bloods cells surround and digest foreign organisms and chemicals
Fevers: High temperatures slow the growth of bacteria and speeds up the body’s defenses.
Inflammation: chemicals released by damaged cells cause capillaries to expand, more blood with more white blood cells to surround pathogens.

6. Specific Immunity
Molecules that don’t belong in your body are called “antigens”
Lymphocytes (white blood cells) respond
Killer T cells release enzymes to destroy invaders
Helper T cells turn on the immune system
B cells form antibodies that attach to the antigen and make it useless.
Memory B cells remain in the body and defend against another invasion by that same pathogen.

7. Active Immunity vs. Passive Immunity
In active immunity your body makes its own antibodies in response to an antigen.
In passive immunity, antibodies that have been produced in another animal are introduced into your body.

8. Vaccines
Vaccines are a form of the antigen that gives you active immunity against a disease.
Example: Measles vaccine is injected into your body. Your body forms antibodies against the measles antigen. If you later encounter the same measles, the antibodies that are needed are already in your body

9. Infectious Diseases
Louis Pasteur learned that micro-organisms might cause disease in humans. He also discovered that they could spoil wine and milk.
He developed pasteurization – a process of heating a liquid to a temperature high enough to kill bacteria.

10. Koch’s Rules
Louis Pasteur knew bacteria caused disease, but he didn’t know which bacteria caused a certain disease. Robert Koch developed a way to isolate and grow one type of bacteria at a time.

11. Keeping Clean
Joseph Lister recognized the relationship between infection rate and cleanliness. He dramatically reduced the number of deaths among his surgery patients by washing their skin, his hands and his instruments and bandages with carbolic acid. More and more of his patients began to survive surgery.

12. How Diseases are Spread
A disease caused by a virus, bacterium, protist or fungus is spread from an infected organism or the environment to another organism.
Direct contact with the infected organism through water, air, food, contact with contaminated objects and by disease carrying organisms called biological vectors (dogs, rats, fleas, mosquitoes, birds, flies, etc.)

13. Sexually Transmitted Diseases
Bacterial STD’s – gonorrhea, chlamydia, and syphilis are all caused by bacteria and may be treated with antibiotics.
Viral STD’s – herpes and HIV are both caused by viruses. The symptoms may be treated by antiviral medications, but there is no cure and no vaccine.

14. Noninfectious Diseases
Allergies – an overly strong reaction of the immune system to a foreign substance.
Allergens – substances that cause an allergic response. These can cause hives, diarrhea, runny nose, asthma
Your immune system forms antibodies and releases chemicals call histamines the promote red, swollen tissues.

15. Diabetes A chronic disease associated with insulin levels.
Type I – too little or no insulin production.
Type II – body doesn’t properly process insulin.

16. Chemicals and Disease
Chemicals that are harmful to living things are called “toxins”
Toxins can cause birth defects, cell mutations, cancers, tissue damage, chronic diseases, and death.
How much and for how long you take in a toxin determines how it affects you.

17. Cancer Uncontrolled cell growth
Cells do not function as part of your body.
These cells take up space and interfere with normal body functions
Cells travel through the body via blood and lymph vessels
Produce tumors anywhere

18. Causes of Cancer Smoking
Exposure to certain chemicals called carcinogens
Exposure to X-rays, nuclear radiation and UV radiation
Smoked or cured foods
Food additives
Some viruses
Genetic predisposition

19. Treatment Surgery to remove cancerous tissue
Radiation with X-rays to kill cancer cells
Chemotherapy – the use of chemicals to destroy cancer cells.

20. Prevention Lifestyle choices: No smoking No drinking
Healthy diet – limit fats, salt and sugar
Use sunscreen and limit sunlight exposure
Careful handling of home and garden chemicals