How does your body defend itself against microbes? Today we are learning: • How our understanding of the spread and prevention of disease has developed • About the natural barriers we have to fight infection • That we make antibodies and specialised cells in the blood to fight microbes Keywords: Hygiene, immunity, vaccination, antibodies. Starter: Label the microbes Extension: What happens to your body when you catch a cold? Discuss in pairs.
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How does your body defend itself against microbes?
Today we are learning:• How our understanding of
the spread and prevention of disease has developed
• About the natural barriers we have to fight infection
• That we make antibodies and specialised cells in the blood to fight microbes
Keywords:
Hygiene, immunity, vaccination, antibodies.
Starter:
Label the microbes
Extension:
What happens to your body when you catch a cold? Discuss in pairs.
A virus is a simple organism which does not completely display ALL the characteristics of living things. It consists of a protein coating and a strand of genes.
Yeast is a fungus and as can be seen below, it has a more complex structure than the other two types of microbes.
By the end of the lesson you should be able to describe: • how micro-organisms can cause infections and can be passed from one person to another.
• how bias, lack of evidence or misconceptions can give rise to inappropriate theories and the role of scientists in questioning these’.
Learning outcomes
John Snow (1813-1858) was a British physician.
He is considered to be one of the fathers of epidemiology, because of his work in tracing the source of a cholera outbreak in Soho, England, in 1854.
The London cholera epidemic
We know cholera is caused by a bacterium (Vibrio cholerae).Symptoms include chronic diarrhoea, low blood pressure and dehydration.Infected patients can die within 3 hours if left untreated.
In 1854, there was a cholera outbreak in Soho, London.
It had devastating outcomes with over 500 fatalities.
Nearly all families lost at least one member (regardless of socioeconomic class).
People thought that cholera was caused by ‘bad’ air
John Snow did not believe this and he began to collect evidence
John Snow mapped where the cholera cases occurred
• Complete the worksheet including report (15 minutes total)
Your task
By talking to local residents, Snow identified the source of the outbreak as the public water pump on Broad Street.
Snow later used a spot map to illustrate how cases of cholera were centred around the pump.
Snow concluded that all the people infected with cholera had drunk water collected from the Broad Street well.
It was later discovered that a leaking cess pit containing sewage was only 3ft away from the well and was contaminating the water.
Snow's studies of the pattern of the disease were convincing enough to persuade the local council to disable the well pump by removing its handle.
This caused the number of cholera cases to decrease rapidly.
Edward Jenner and vaccination
Many years ago there was a disease called SMALLPOX,
people living in the countryside noticed that
milkmaids never seemed to catch the deadly disease.
This was because they were subjected to another similar
infection caught from the cows they milked (cowpox).
Edward Jenner
Edward Jenner
In 1796 a doctor called Edward Jenner carried out a famous experiment on an
eight year old boy called James Phipps.
Edward Jenner
Jenner took pus from someone with mild cowpox and put it into a cut in the
eight year olds arm.
He never caught smallpox, for many years after that Jenner conducted lots of
experiments to prove that our bodies can become
IMMUNE.
Questions:
• Do you think the experiment that Dr. Jenner did on James was a dangerous one?
• If you were James' parents, would you let Dr. Jenner do the experiment on James? What questions would you ask Dr. Jenner?
• If you were James, now that you are safe from contracting smallpox, would you advise your friends to have the vaccination?
Homework Complete the Jenner and vaccination work sheet