3.2 Flashcards
Immunity
Recovery from some diseases,which we now know to be infections, leads to freedom from the same disease again,often for life
What are vaccines?
The simplest,most efficient and cost-effective way to prevent/reduce the frequency of certain diseases.
What are the scares of vaccines?
- overload our immune system-less able to react to other diseases (AIDS, cancer)
- possible side effects-although usually mild and not life threatening
Diseases caused by bacteria
3
- tuberculosis
- cholera
- typhoid
Diseases caused by viruses
5
Rubella Influenza Measles Mumps Polio
How do pathogens enter the body?
4
•wounds •the respiratory system •the digestive system •sexual transmission ( as a result of unhygienic conditions or contact with infected people)
How do some types of bacteria/viruses make us feel ill?
They reproduce rapidly in the body
How does bacteria make us feel ill
By producing toxins
How do viruses make us feel ill?
By causing cell damage
How platelets help to form a barrier to a cut
5
- the skin is cut,starts to bleed meaning blood leaks out of the body
- platelets change the blood protein fibrinogen into fibrin forming a network of fibres in the cut
- red blood cells are trapped in the fibres forming a blood clot
- the clot gardens to form a scab. This keeps the skin clean and gives it time to heal
- in time the scab falls off
How white blood cells help to defend against pathogens
•phagocytes engulf microorganisms and make enzymes which break down the microorganism
•lymphocytes make antibodies which react with the microorganism and deactivates it
They also make antitoxins which destroy the poisonous toxins that microorganisms make
How do vaccinations protect humans from infection?
3
•they contain dead/weakened microorganisms that can no longer cause disease.
These trigger your lymphocytes to make antibodies-these destroy the microorganism
•some remain in your body to fight off the pathogen quickly if it enters your body again,preventing it from causing disease
^ you are now immune
