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Physical and Chemical Barriers Skin- first line of defense Few pathogens can get through the first layers skin cells Tears and saliva- contain enzymes.

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Presentation on theme: "Physical and Chemical Barriers Skin- first line of defense Few pathogens can get through the first layers skin cells Tears and saliva- contain enzymes."— Presentation transcript:

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2 Physical and Chemical Barriers Skin- first line of defense Few pathogens can get through the first layers skin cells Tears and saliva- contain enzymes that destroy pathogens Mucous membranes- produce mucous, a sticky substance that traps pathogens and helps dispose of them Line mouth, nose, bronchial tubes, and others

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4 Cilia- hair-like projections that line parts of the respiratory system Sweep mucus and pathogens to the throat, where they can be swallowed or coughed out Gastric Juice- destroys pathogens in the stomach

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7 Immune System Network of cells, tissues, organs, and chemicals that fight of pathogens The Inflammatory Response A reaction to tissue damage caused by injury or infection Blood vessels around the injury or infection expand to allow more blood to the area

8 Fluid and cells from the blood stream move into the area

9 Swelling and pain results from the pressure of fluid on nerves Phagocyte- white blood cell that attacks invading pathogens Engulf pathogens and kill them with chemicals Pus forms- dead white blood cells and damaged tissue Specific defenses are activated

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11 Specific Defenses Specific defenses react to an invasion as a result of the body’s ability to recognize certain pathogens and destroy them. Immune response= immunity= the state of being protected against a particular disease. Your immune system has a “memory”

12 Specific types of white blood cells, T cells and B cells, have been activated by antigens and become memory cells Antigen- found on the surfaces of pathogens and toxins Capable of triggering an immune response Memory cells circulate in blood stream and lymphatic system

13 If memories cells recognize the antigens of a former invader certain white blood cells, B cells, make cells to stop it Antibodies- acts against a specific antigen, destroys or blocks pathogens from entering cells Killer T cells- attack and destroy infected body cells Ex: If you have had the measles or a vaccination your body remembers antigens If measles enter again antibodies will attack immediately

14 Active Immunity Occurs when your body develops antibodies for a specific pathogen Natural active immunity- when you are exposed to invading pathogens Artificial active immunity- antibodies develop in response to a vaccine Vaccine- dead or weakened pathogens that are injected into the body to stimulate the immune response

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16 Active immunity can last a lifetime for some pathogens Other pathogens require repeating immunizations (vaccine)

17 Passive Immunity Receiving antibodies from another person or animal Passed from mother to child during pregnancy and nursing From injection of antibodies that were produced by animal are human that is immune to disease. This type of immunity is short lived

18 Care of the Immune System Eat balanced diet Drink water Get plenty of rest Fatigue reduces the effective ness of immune system Manage stress Avoid sharing Keep immunizations up to date Avoid sexual contact- some STDs destroy immune system

19 Four types of Vaccines Live-virus- from pathogens made in lab under conditions to cause the pathogen to lose some disease causing property Measles, mumps, rubella and chicken pox Killed virus- from dead pathogens Still stimulated immune response Flu, hepatitis A, rabies, and cholera

20 Toxoids- inactivated toxins from pathogens are used Tetanus New and second-generation-new types in development by scientist

21 Immunizations for All A person who is vaccinated not only protects themselves but those around them You will not spread the disease to other Keep immunization up to date Tetanus Diphtheria Pertussis (whooping cough) Measles, mumps, and rubella (MMR) Chicken pox Human Papillomavirus HPV Most high schools and colleges require some of these


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