Transcript Preventing Communicable Diseases

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
 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
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
 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
pathogens
 Engulf pathogens and kill them with chemicals
 Pus forms- dead white blood cells and damaged tissue
 Specific defenses are activated
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”
 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
 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
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
 Active immunity can last a lifetime for some pathogens
 Other pathogens require repeating immunizations
(vaccine)
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
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
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
 Toxoids- inactivated toxins from pathogens are used
 Tetanus
 New and second-generation-new types in
development by scientist
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