Preventing and treating disease

Question 1

When does natural immunity occur?

Answer 1

• Production of T and B memory cells when the body meets a pathogen - known as natural active immunity - when the body meets the pathogen again the body will recognise the antigens and destroy it quickly
• Some antibodies cross the placenta from mother to fetus, also the first milk a mammaliam mother makes is colostrum, which is high in antibodies, these are allowed to pass into the blood stream without being digested - this is natural passive immunity
• NPI lasts until the baby makes its own antibodies - and the antibodies are likely to be relevant to pathogens in its environment

Question 2

What is artificial immunity used for?

Answer 2

diseases that are potentially deadly before the immune system can make the antibodies they need

Question 3

What is artificial passive immunity?

Answer 3

antibodies formed in one individuals (often an animal) are extracted then inject into the bloodstream of another individual

this gives temporary immunity

can be lifesaving in a person who is infected

Question 4

What is artificial active immunity?

Answer 4

the immune system of the body is stimulated to make its own antibodies to a safe form of an antigen (a vaccine)

it is injected into the blood stream

use a weakened or inactive pathogen

Question 5

What are the ways of making the pathogen is made safe so that there is no risk of infection?

Answer 5

• • may be killed or inactivated bacteria and viruses, e.g. whooping cough
    
    • attenuated (weakened) strains of live bacteria or viruses, e.g.polio
    • Toxin molecules that have been altered and detoxififed, e.g. tetanus
    • isolated antigens extracted from the pathogen, e.g. influenza
    • genetically engineered antigens, e.g. hepititis B

Question 6

What are the steps for atrificial active immunity?

Answer 6

1. small amount of the safe antigen, known as the vaccine, are injected into the blood
2. the primary immune response is triggered by the foreign antigens and produced antibodies and memory cells
3. if you come into contact with a live pathogen, the secondary immune response is triggered and you destroy the pathogen rapidly before you suffer the symptoms of the disease

Question 7

What is the difference between an epidemic and a pandemic?

Answer 7

epidemic - a communicable disease spread rapidly to a lot of people at a local or national level

a pendemic is when the same disease spreads rapidly across a number of countries and continents

Question 8

Why is vaccination an example of active immunity?

Answer 8

body produces its own antibodies and memory cells to destroy the pathogen

activated lymphocytes and specific memory cells remain