Preventing Communicable Diseases

Physical and Chemical BarriersSkin- 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 themLine mouth, nose, bronchial tubes, and others

Cilia- hair-like projections that line parts of the respiratory systemSweep mucus and pathogens to the throat,

where they can be swallowed or coughed outGastric Juice- destroys pathogens in the

stomach

Immune SystemNetwork of cells, tissues, organs, and

chemicals that fight of pathogensThe Inflammatory ResponseA reaction to tissue damage caused by injury

or infectionBlood vessels around the injury or infection

expand to allow more blood to the area

Fluid and cells from the blood stream move into the area

Swelling and pain results from the pressure of fluid on nerves

Phagocyte- white blood cell that attacks invading pathogensEngulf pathogens and kill them with chemicals

Pus forms- dead white blood cells and damaged tissue

Specific defenses are activated

Specific DefensesSpecific 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”

Specific types of white blood cells, T cells and B cells, have been activated by antigens and become memory cellsAntigen- found on the surfaces of pathogens

and toxinsCapable of triggering an immune response

Memory cells circulate in blood stream and lymphatic system

If memories cells recognize the antigens of a former invader certain white blood cells, B cells, make cells to stop itAntibodies- acts against a specific antigen,

destroys or blocks pathogens from entering cellsKiller T cells- attack and destroy infected body

cellsEx: If you have had the measles or a vaccination

your body remembers antigensIf measles enter again antibodies will attack

immediately

Active ImmunityOccurs when your body develops antibodies

for a specific pathogenNatural active immunity- when you are

exposed to invading pathogensArtificial active immunity- antibodies develop

in response to a vaccineVaccine- dead or weakened pathogens that

are injected into the body to stimulate the immune response

Active immunity can last a lifetime for some pathogens

Other pathogens require repeating immunizations (vaccine)

Passive ImmunityReceiving antibodies from another person or

animalPassed from mother to child during

pregnancy and nursingFrom injection of antibodies that were

produced by animal are human that is immune to disease.

This type of immunity is short lived

Care of the Immune SystemEat balanced dietDrink waterGet plenty of rest

Fatigue reduces the effective ness of immune system

Manage stressAvoid sharingKeep immunizations up to dateAvoid sexual contact- some STDs destroy

immune system

Four types of VaccinesLive-virus- from pathogens made in lab under

conditions to cause the pathogen to lose some disease causing propertyMeasles, mumps, rubella and chicken pox

Killed virus- from dead pathogensStill stimulated immune responseFlu, hepatitis A, rabies, and cholera

Toxoids- inactivated toxins from pathogens are usedTetanus

New and second-generation-new types in development by scientist

Immunizations for AllA person who is vaccinated not only protects

themselves but those around themYou will not spread the disease to other

Keep immunization up to dateTetanusDiphtheriaPertussis (whooping cough)Measles, mumps, and rubella (MMR)Chicken poxHuman Papillomavirus HPV

Most high schools and colleges require some of these