Unit 3 Infectious Disease

Terms To know Infectious Disease : disease caused by a microscopic germs that can pass from one thing to another. Some cannot pass to new individuals. 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 (Ex: bacteria, fungi, protists). Pathogens : any agent that causes diseases. 2 most common pathogens Other Pathogens 1. Bacteria - fungi 2. Viruses - protists - parasitic worms

Types of Bacteria (common) Unicellular microorganism that can cause disease; majority are harmless, but some are pathogenic (1%) Can kill bacteria with antibiotics Binary Fission- reproduction of bacteria by splitting of the body into 2 new bodies. Types of Bacteria (common) Strep throat Food/water poisoning Urinary-tract infection Tuberculosis Staph Infection- MRSA (antibiotic resistant) Yersinia pestis

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 . Polio hepatitis . Measles influenza . Tetanus cold sores (herpes simplex type 1) Chicken pox . Small Pox Common cold

Other pathogens Fungi (mushrooms, mold, mildew) athlete’s foot, ringworm, yeast infection Protists (single or multi-celled organism) Malaria, giardia infection Parasitic Worms (multicellular organism) tapeworm (water/meat), flatworm (water), hookworm (feces/soil), roundworm (meat)

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

External and Internal Defense Innate Immunity- non specific defense Skin Epidermis: physical barrier Chemical Warfare on Germs: tears, saliva, ear wax, fever, inflammatory response Mucus Membranes: line body cavities of respiratory, urinary, and digestive tract Stomach Acids Helpful Microorganisms Phagocyte Cells (patrol the circulatory system “find and eat” unnatural cells)

Your Immunity Acquired Immunity- antigen specific defense 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 (live, killed, toxoid, 2nd generation) Antibiotics – drugs that kill or limit the growth of bacterial infections not viruses.

How the Immune System Works Pathogens – disease causing agent gets past external innate defense mechanisms. Macrophage – phagocyte that engulfs pathogen using cytoplasmic extensions and ingest and digest and display it Helper T cells – drive the immune system response; activation of B Cells and killer T Cells Killer T cells – kills or neutralizes infected cells. B cells – bind to antigen divides & clones. Produce antibodies and remembers the antigen. 6. Antibodies – protein that marks antigen for destruction & neutralizes it by blocking binding sites 7. Suppressors T cells – turns off immune system when the infection is cleared. Regulates self-tolerance (prevents body from not attacking own cells) Memory T cells – remembers the antigen & immediately attacks (secondary immune response)