defences against infection (including vaccination)

what is primary defence in the body?

a first line of defence against pathogens. they prevent pathogens from entering the body, acting as a physical and chemical barrier. It is non-specific as it doesn’t target specific pathogens.

Give examples of primary defence against pathogens

• Earwax is bactericidal

• Tears have antibacterial enzymes

• Platelets clot blood and retain the skins barrier to prevent pathogens entering via wounds

• Saliva is antibacterial, and cleans the mouth

• Nose hairs and mucus trap dirt and microbes

• The skin prevents entry as a whole

What does secondary disease involve?

Antibodies and antitoxins

How do antibodies stop pathogens from entering or damaging cells?

They combine with these pathogens to block them from entering the cells.

What causes pathogens to agglutinate, and why is it helpful?

Antibodies do this - and this means to clump the pathogens together. This reduces the chance that the pathogens will spread through the body and makes it possible for phagocytes to ingest multiple pathogens at once

What produces the antibodies and antitoxins in the body?

White blood cells

possible exam question: Describe different ways white blood cells protect us from infections.

They produce antibodies AND antitoxins as well as ingest pathogens.

They destroy pathogens in this way, neutralising toxins and stopping pathogens with antibodies

They also rapidly produce antibodies upon reinfection

What must be done to a pathogen before adding it to the serum?

It must be weakened by:

Just weakening it idk

Killing it

Inactivate the toxins

How does vaccination make someone immune to a disease?

1. An inactive form of the pathogen is introduced

2. This stimulates the production of white blood cells, and triggers immune response

3. The phagocytes then produce antibodies which attack the pathogen, and it is then harmless

4. The body now has defences against the pathogen with memory cells in the blood

5. If that pathogen then attacks the body, the memory cells produce antibodies to attack and destroy quickly

What does MMR stand for?

Measles, Mumps and Rubella

What does DTP stand for?

Diptheria, Tetanus and Polio

Describe differences in antibody production after infection compared with after vaccination.

• Less lag time for the production of antibodies

• Faster rise in the number of antibodies

• The response lasts for a larger amount of time

What are two types of immunity?

Passive and active

Passive is when antibodies are given from another organisms, like via breast milk

Active immunity comes from the body creating antibodies by exposure to the disease naturally or artificially

What are advantages to vaccination?

• Diseases once common are now fairly rare due to widespread vaccination

• Prevents epidemics if a large proportion of the population is vaccinated

What are some disadvantages to vaccination?

The vaccine doesn’t always give immunity

There can be some side effects which are very harmful

What is herd immunity?

The principle that if many people were vaccinated, that means that someone unvaccinated is unlikely to contract the disease. It stops it from spreading.