1. Unit 3
Infectious Disease

2. Terms To know
Infectious Disease : disease caused by a microorganism that can pass from one living thing to another
Communicable Disease : an infectious disease that is passed from one person to another
Microorganisms : a living thing that can be seen only with a microscope
Pathogens : any agent that causes diseases
2 most common pathogens Other Pathogens
1. Bacteria fungi
2. Viruses protists
- parasitic worms

3. Types of Bacteria (common)
Unicellular microorganism that can cause disease; majority are harmless, but some are pathogenic (1%)
Can kill bacteria with antibiotics
Types of Bacteria (common)
Strep throat
Food/water poisoning
Urinary-tract infection
Tuberculosis
Staph Infection

4. Types of viruses (common)
A microscopic disease causing particle consisting of genetic material and a protein coat
Attacks and kills living cells to make new viruses
NO CURE
Types of viruses (common)
mononucleosis
hepatitis
influenza
cold sores (herpes simplex type 1)
Chicken pox
Common cold

5. Other pathogens Fungi (mushrooms, mold, mildew)
athlete’s foot, ringworm (jock itch)
Protists (Unicellular organism)
malaria
Parasitic Worms (multicellular organism)
tapeworm, liver fluke (snails), trichinosis (from pigs - pork foods)

6. How are Infectious Diseases Spread?
1. Through the air (chicken pox, flu, tuberculosis)
2. Contact with Contaminated Objects (poison ivy)
3. Person to person (HIV, STDs)
4. Food and Water (salmonella, E-coli)
5. Animal Spreading Diseases (malaria, rabies, Lyme disease)

7. Defenses Against Infection
Ways our body copes with infection: Innate immunity
Skin Epidermis: physical barrier
Chemical Warfare on Germs: tears, saliva, ear wax, fever, inflammatory response (fluid surrounds cells)
Mucus Membranes: line body cavities of respiratory, urinary, and digestive tract
Stomach Acids
Helpful Microorganisms

8. Your Immunity Protection against developing a certain disease.
Active immunity- natural or artificially developed immunity.
Passive immunity- antibodies acquired from mother to child during pregnancy or injected.
Immune system – protects body from disease
Vaccination – injection of a small amount of a pathogen that will provide protection against an infections disease
Antibiotics – drugs that kill or limit the growth of bacterial not viruses.

9. How the Immune System Works
Pathogens – disease causing agent.
Macrophage – phagocyte cell; engulfs pathogen and destroy them.
Helper T cells – lymphocyte; triggers production of B Cells and Killer T Cells
Killer T cells – lymphocyte; kills or neutralizes infected cells
B cells – bind to specific antigen & produce antibodies
6. Antibodies – protein; marks antigen for destruction & neutralize it from infecting healthy cells
7. Suppressors T cells – lymphocyte; turns off immune system when the infection is cleared.
Memory T cells – lymphocyte; remembers the antigen & immediately attacks (secondary response)