Immune System

Homeostasis Homeostasis: the process by which organisms keep internal conditions relatively constant despite changes in their external environments pg 1031

Fight infection through production of cells that inactivate foreign substances of cells. pg 1036

Disease caused by  Genetics: cancer, hemophilia, sickle cell anemia  Environmental factors: cigarette smoke, asbestos  Pathogens: micro-organisms that cause disease  Bacteria  Viruses  Fungi  Protists pg 1033

Pathogens bacteriaviruses  Require nutrients, energy, disrupts homeostasis Break down cells for food (tuberculosis) Toxins: released by pathogen and travels through body (diphtheria)  Requires host cell to replicate and synthesize self Infect cells Harm cells pp 480, 481, 485, 488

Diseases Caused by Bacteria DiseaseBacteriumEffect on Body TetanusClostridium tetani Severe muscle spasms, paralysis, death TuberculosisMycobacterium tuberculosis Fatigue, weight loss, mild fever, night sweats chronic cough DiphtheriaCorynebacterium diphtheria Sore throat, low-grade fever Strep ThroatStreptococcus pyogenes Fever, sore throat, swollen glands Tooth DecayStreptococcus mutansDestruction of tooth enamel pg 486

Diseases Caused by Viruses DiseaseEffect of BodyTransmission Common cold Sneezing, sore throat, fever, headache, muscle ache Contact with contaminated objects, droplet inhalation Influenza Body aches, fever, sore throat, nasal congestion, headache, dry cough, fatigue Contact with contaminated objects, droplet inhalation Smallpox High fever, fatigue, head and back aches, rash Contact with contaminated objects, droplet inhalation WartsNoncancerous growth on the skinContact with warts AIDSHelper T cells, which are needed for normal immune function are destroyed Contact with contaminated blood or bodily fluids, pregnant women to babies during delivery or breastfeeding pg 489

Germ Theory  Pasteur and Koch: independently determined infections are caused by germs (pathogens)  Koch’s Postulates pp

Steere  Identified Lyme’s disease by reproving Koch’s postulates  pg 1032, figure 40-2

How diseases are spread  Physical contact hands  Contaminated food and water Food poisoning  Vectors: infected animals, eg mosquitos Anthrax through sheep pg 1034

Immune System  Nonspecific defenses  Specific defenses pp

1 st Line of Defense Nonspecific Keep pathogens out!!!! saliva antibacterial enzymes mucus linings traps dirt and microbes cilia tiny hairs in nose and bronchi tears antibacterial enzymes stomach acid low pH kills harmful microbes ***skin prevents entry*** Pg 1036

2 nd Line of Defense (nonspecific response)  Inflammatory Response Nonspecific reaction to tissue damage by injury or infection WBC or phagocytes called macrophages attack pathogen fever – chemicals released by body increase core temp (slows down growth)  Interferon Nonspecific response to a viral infection Protein produced by infected cells. Interferes with synthesis of viral proteins & helps block viral replication (slows down growth) pg 1037

Inflammatory Response Skin Wound Bacteria enter wound Phagocytes: enter area and engulf bacteria and cell debris Phago = eats; cytes = cells Capilary pg 1037

Specific Defenses: Immune Response: body reacts with a series of specific defenses to attack pathogens with a particular antigen. Antigen: substance of a pathogen that triggers an immune response. pg 1038

Immune Response  Humoral Immunity Bodily fluids Bone marrow B lymphocytes B cells Humor = fluid Lymph = water, fluid Cyte = cell  Cell-mediated Immunity Living inside cells Thymus gland T lymphocytes T cells pp

Humoral Immunity  B cells  Plasma cells  Antibodies  Memory B cells  1 st recognize pathogen. Grow rapidly.  Produce antibodies which is specific for a particular antigen. Short lived.  Protein that binds tags antigen attacking disarming.  Retain ability to produce antibodies for specific antigen. Reduce chance of second infection. Lives for years. pp

Cell-mediated Immunity  T cells  Helper T cell  Memory T cell  Killer T cell  Suppressor T cell  Activates Killer T and produces memory T cells  Retain memory for antigen. Lives for years  Track and kill pathogen with the antigen.  Release substance that shuts down Killer T’s pg 1040

Summary to Immune Response Antigen Macrophage Helper T - Cell Active Cytotoxic T-Cell Kills Infected Cells Memory T- Cell Active B - Cell Plasma Cell Antibodies Deactivates Antigens Memory B-Cell Humoral Immunity Cell-mediated Immunity

Fighting Back  Antibiotics: compounds that block the growth and reproduction bacteria without harming the cells of the human or animal host.  Vaccines: weakened or killed pathogen build immunity to disease. Useful for preventing bacterial and viral infections. pp 486, 1035, 1042

Building Immunity  Acquired immunity – cowpox and smallpox  Active immunity – from infection and vaccine Vaccine:  Passive immunity – breastfed baby pp

Allergies  Overreaction to immune system antigens known as allergens  Asthma is an example of this pp

Autoimmune disease  Body fails to recognize self. Sees self as an invader. Attacks  Multiple Sclerosis, psoriasis, Type I diabetes, rheumatoid arthritis, myasthenia gravis pg 1044

Immunodeficiency disease  Immune system does not develop – boy in the bubble  Acquired Immune Deficiency Syndrome HIV – Human Immunodeficiency Virus Attacks helper T-cell Pp

Summary to Immune Response Antigen Macrophage Helper T - Cell Active Cytotoxic T-Cell Kills Infected Cells Memory T- Cell Active B - Cell Plasma Cell Antibodies Deactivates Antigens Memory B-Cell Humoral Immunity Cell-mediated Immunity

HIV Transmission  Sexual intercourse – bodily fluids  Shared needles – blood  Blood exposure – blood  Mother/child: pregnancy birth, feeding – both  ABSTINENCE is the only no risk behavior pg 1047