Immune System & Disease Chapter 31

Germ Theory In the 1850’s Pasteur proposed the Germ Theory Specific microorganisms cause disease  Types of pathogens that cause disease.  Bacteria  Viruses  Fungi- occur in warm damp areas  Protozoa  Parasites

How are Bacteria and Viruses Different?

Bacteria The Prokaryotes Reproduce by Binary Fission Autotrophic and Heterotrophic

Helpful Bacteria in Nature  Decomposers  Nitrogen cycle  Industry  Food- yogurt!

Harmful Bacteria Cause disease by RReleasing toxins into the body DDirectly break down tissue of organism for food

Viruses Latin for Poison Not living Require a host cell to reproduce!! Consist of DNA or RNA surrounded by a protein coat

Viral Infection Virus enters host cell Host cell produce viral DNA Host cell bursts

Retroviruses  Viruses that have RNA as their genetic material  HIV leads to AID’s HIV kills our Helper T cells

Common Viruses  Flu  Chicken Pox  Warts  Mono  Rabies

TreatmentTreatment Antibiotics Vaccination Antibiotics Vaccination Bacteria Viruse s Immunity from vaccination can be temporary or permanent

How our Bodies defend against pathogenic organisms Nonspecific vs. specific defenses

Nonspecific Defense SSkin- the most important! OOil and sweat create an acidic environment MMucus, saliva, sweat, tears, contain lysosomes that break down bacterial cell walls IInflammatory response- fever and swelling

Types of Immunity Body mounts an active response to the pathogen The development of antibodies in response to stimulation by an antigen Produced by vaccination or getting the disease B ody mounts an active response to the pathogen T he development of antibodies in response to stimulation by an antigen P roduced by vaccination or getting the disease Temporary immunity A mother provides passive immunity to her baby in her uterus and after birth by breastfeeding T emporary immunity A mother provides passive immunity to her baby in her uterus and after birth by breastfeeding Active Passive

Specific Defense The Antibody Antigen Reaction An antigen triggers an immune system response Antigens are specific for each pathogen Lymphocytes produce antibodies. Once formed the antibodies are held in memory B cells (lymphocytes) so that the body has permanent immunity to that disease An antigen triggers an immune system response Antigens are specific for each pathogen Lymphocytes produce antibodies. Once formed the antibodies are held in memory B cells (lymphocytes) so that the body has permanent immunity to that disease

Antibodies help kill the intruder by: 1. Binding to antigens on surface of microbes 2. Clustering antigens together