Vaccination & Immunisation Keeping Healthy B1c (2)

OBJECTIVES Grade C - D Describe how the symptoms of an infectious disease are caused Describe how pathogens are destroyed Describe what causes immunity to a disease Explain the difference between passive and active immunity Grade A* - C Explain why pathogens are described as specific Explain the process of immunisation Discuss the benefits and risks associated with immunisation

Name 10 diseases Which of these can you be immunised against?

Vaccination & Immunisation What are they? Complete w/s B1c6

What happens when you get ill? What is happening in your body? What is fighting it?

White blood cells If microbes enter our body they need to be neutralised or killed. This is done by WHITE BLOOD CELLS: White blood cells do 3 things: 1)They eat the microbe (these white blood cells are called “phagocytes”) 2)They produce antibodies to neutralise the microbe (“lymphocytes”) 3)The produce antitoxins to neutralise the poisons produced by microbes (lymphocytes again)

Antitoxin links to the toxin and neutralises its effect. The toxin is now harmless. This happens on a large scale and reduces the effects of the infection. toxins bacterium white blood cell antitoxins

Task/Homework Complete w/s B1c7

Using Antibiotics Antibiotics can be used to kill bacteria. However, there are two problems: 1) Overuse of antibiotics can lead to bacteria becoming resistant (e.g. the MRSA “superbug”). This means that antibiotics must be used sparingly. 2) Antibiotics have no effect on a virus, like the common cold. It is difficult to kill a virus without damaging body tissue. A virus is usually allowed to “run its course”.

Passive vs. Active Immunity Read p25 of the student book Complete w/s B1c8

Fighting disease NATURAL IMMUNITY This is when antibodies are produced by a person when needed or they are passed on by the mother during pregnancy. ARTIFICIAL IMMUNITY Can be done in two ways: 1)A vaccine with dead microbes is injected – the body is “tricked” into producing antibodies ready for the real thing. This is called PASSIVE IMMUNISATION 2)The antibodies are injected directly into the body – this is called ACTIVE IMMUNISATION.

Researching new medicines Before new drugs can be approved they have to go through three stages: 3. Does it work? People with the illness are tested on. This can involve using a “placebo” – a dummy pill 1. Is it toxic? Tests are done on animals 2. Is it safe for humans? Human volunteers trial the drug

1.[Penicillin/Paracetamol] can only be obtained on prescription. 2.Antibiotics have been very successful in the [treatment/cause] of disease. 3.[All/Not all] drugs are antibiotics. 4.The discovery of penicillin was [planned/an accident]. 5.Antibiotics only work on ______. Some medicines that are not ______ work by suppressing the symptoms of the illness. Symptoms are the body’s response to the waste _____ made by microbes. An antibiotic _____ microbes that cause the symptoms. Medicines

PLENARY 1.How are the symptoms of a disease caused? Cell damage; toxins released by pathogens 2.How do antibodies work? They lock on to antigens on the surface of the pathogen, allowing them to be destroyed more easily 3.How do we become immune to a pathogen? Vaccination OR by suffering from the disease 4.What is the difference between active & passive immunity? 5.How many antibodies can your body produce? Why? One for each disease you are exposed to because they are specific 6.How are we immunised against a disease? Injected with a vaccine to make the body produce the antibodies for that disease 1-2 points = E 3-4 points = D 5-6 points = C 7 points = B 8 points = A 9 points = A*

OBJECTIVES Grade C - D State that the symptoms of an infectious disease are caused by cell damage or by toxins produced by the pathogens Recall that antibodies lock on to antigens causing the death of the pathogens Describe how immunity to pathogens comes from prior infection Explain the difference between passive and active immunity Grade A* - C Explain how each pathogen has its own antigens and that specific antibodies are needed Explain the process of immunisation Discuss the benefits and risks associated with immunisation