Transcript Vaccination & Immunisation

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)
bacterium
white
blood cell
antitoxins
toxins
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.
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:
1. Is it toxic? Tests are done on animals
2. Is it safe for humans? Human
volunteers trial the drug
3. Does it work? People with the illness
are tested on. This can involve using a
“placebo” – a dummy pill
Medicines
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.
PLENARY
1.
How are the symptoms of a disease caused?
•
2.
1-2 points = E
3-4 points = D
5-6 points = C
7 points = B
8 points = A
9 points = A*
Cell damage; toxins released by pathogens
How do antibodies work?
•
3.
They lock on to antigens on the surface of the pathogen, allowing
them to be destroyed more easily
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?
•
6.
One for each disease you are exposed to because they are
specific
How are we immunised against a disease?
•
Injected with a vaccine to make the body produce the antibodies
for that disease
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