2 Lesson 1VocabularyCommunicable disease – Disease caused by direct or indirect spread of pathogens from one person another.Pathogens- tiny microorganisms that cause disease by infecting or invading the cells and tissues of the body.Bacteria – one-celled microorganisms that is the most widespread of living things. Not all bacteria cause disease, but a lot do.Saprophytes- bacteria that digest non-living food materials, such as meat or milk.
3 PARASITES- bacteria that feed on a living plant or animal HOST- the plant or animal the bacteria feeds from.RESIDENT BACTERIA- bacteria that live in your mouth, intestines and skin and help protect you from harmful bacteria.A single bacterial cell divides every min. COMPETITION-Kills many of them to keep them under controlTOXINS – bacteria that produces poisons. Ex. Botulism, tetanusBacterial diseases include: pneumonia, food poisoning, tetanus, tuberculosis, strep throat, syphilis and gonorrhea.
4 VIRUSES – small, simple life-like forms, smaller than bacteria VIRUSES – small, simple life-like forms, smaller than bacteria. No nucleus, no cytoplasm and no cell membrane. All are parasites.CELL SPECIFIC - They attack only specific cellsRabies- only brain cellsPolio-nervous systemCold- respiratory systemHepatitis – liverMumps and mononucleosis- lymph glandsSmall pox, chicken pox- skin tissues
5 OTHER PATHOGENS Rickettsias- between a bacterium and virus. Grow in intestinal tracts of insects.Insects carries disease to humans- such as lice, mites and ticks.Cause Rocky Mountain spotted fever and Typhus fever.Fungi- simple organisms that cannot make their own food. They are saphrophytesYeast and mushroomsDiseases caused by fungi-athletes’s foot, ringworm, toe fungus.
6 Parasites PROTOZOANS- Single-celled organisms-larger than bacteria Disease producing ones typical in tropical areasCause- malaria, African sleeping sickness and amoebic dysenteryFLATWORMS and ROUNDWORMSFlukes- invade blood, intestines, liver, or lungs.Tapeworms- intestinesRoundworms- intestines, musclesTrichinosis-eating infected pork that is not well-done.
7 Body Defense Mechanisms Disease spreads in many ways:Indirect contact- airborne droplets,touching objects an infected person has touched, using a needle an infected person has touched.Direct Contact- physical contact such as kissing, sexual contact, blood to blood contactContact with animals- mosquito bites, animal bites and scratches-rabies, malaria African sleeping sickness
8 IMMUNE SYSTEMI .Nonspecific Resistance-defense acts the same way each time it is invadedMechanical mechanisms- formation of barriers to keep pathogens out- skin, mucous membranes in your mouth, nose, bronchial tubes, cilia,tears and saliva.Chemical Barriers- acidic digestive juices, chemicals in tears, saliva and sweat. Other chemicals in cellsCells- White blood cells called phagocytes group together to destroy foreign substances- Phagocytosis- the process by which the phagocytes destroy pathogens. Neutrophils- most active phagocyteInflammatory Response- increased blood flow to area to bring phagocytes- redness and swelling occur
9 II. Specific Resistance- A. specific protection against specific types of pathogensB. Keeps a record of the pathogens in case they attack again.C. Lymphocyte- type of white blood cell that fights pathogens- travels through the lymphatic system and circulatory systemLymphocytes multiply in the spleen, tonsils and lymph nodes.T cells and B cells kill pathogens and make antibodies. B cells are stimulated by T cells to make antibodies.3. Antibodies- proteins that destroys or neutralize pathogens. They remain in your blood to fight the pathogen should it return.
10 Prevention Avoid contact with pathogens Bathe or shower everyday Store and prepare food safelyWash your hands after using the restroom, sneezing, changing diapers or preparing foodCover your mouth when sneezing or coughingGet medical treatment- do not bring your sickness to school or workAvoid contact with sick people
11 IMMUNITY Immunity- the bodies natural resistance to many pathogens Active Immunity- the immunity your body develops to protect you from disease – once you have chicken pox your antibodies will protect you from further infection from that disease.Vaccines- preparations of dead or weakened viruses that provide active immunity to some pathogens-smallpox, polio, measles, etc.Vaccination- a process by which vaccine is injected into the body.Passive Immunity- the immunity a mother passes on to her baby for the first few months of life. The baby will develop antibodies to the same diseases as the mother.
12 VaccinesLive-Virus – Weakened virus strong enough to produce antibodies, but not the disease-measles, rubella and oral polio vaccines includedKilled-Virus – not as powerful as live-virus requires booster shots - hepatitis BToxoids – bacterial diseases like diphtheria and tetanus-chemically treated bacteria toxins establish active immunity- boosters neededImmunization is required to enter schools in the U.S.