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7/30/2019 Science Human Biology year 10
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Defending the bodyfrom disease
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25/05/2013PathogensPathogens are things that cause disease.
There are two main types VirusesBacteria
Microscopic
Living cells (some are harmless)
Damage cells by producing toxins
Grow very quickly
Killed by antibiotics
Examples: food poisoning,tetanus, sore throats
Genetic info inside a protein coat(not living)
Damage cells by infecting themthen bursting out
Not affected by antibiotics
Examples: colds, flu, polio,chicken pox
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Pathogens:
our defence against themOur bodies have four major defence mechanisms against invading pathogens
If our skin is cutplatelets seal thewound by clotting
The breathingorgans producemucus to cover the
lining of theseorgans and trap themicrobes
The skin actsas a barrier
Our blood containswhite blood cells
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Fighting disease
White blood cells fight pathogens
White blood cells do 3 things:
1) They eat the pathogen
2) They produce ANTIBODIES tofight the pathogens
3) The produce ANTITOXINS toneutralise the poisons producedby pathogens
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Producing
antibodies
Step 1: The white blood cell seesthe pathogen
Step 2: The cell producesantibodies to fit the pathogen
Step 3: The antibodies fit onto the
pathogens and cause them to clump
Step 4: The pathogens are
eaten by the white blood cells
Youre goingdown
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Vaccines
A small amount of the pathogen is given tosomeone
They make specific ANTIBODIES to it The ANTIBODIES kill/remove the
pathogen The white blood cell which makes that
antibody remains in the blood forever If you become infected with the samepathogen again, the antibodies are madevery quickly
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Vaccines: Pros and cons
Pros Cons
Prevents you sufferingfrom a serious disease
May have side effects
May reduce the cost oftreatments of diseases
for hospitals
The pathogen maybecome resistant
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Using AntibioticsAntibiotics can be used to kill bacteria but....
1) Bacteria can becomeresistant to them so they
do not work anymore (e.g.MRSA- a superbug)
2) Antibiotics do not killviruses
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Antibiotic resistanceBacteria can change (mutate) to become resistant to
antibiotics
1) Variation some strains of bacteriaare resistant and some arent.
2) Competition The non-resistantbacteria are killed by the antibiotic.
3) Survival of the fittest theresistant bacteria survive.
4) Passing on of genes the resistantbacteria reproduce and pass ontheir resistance genes to their
offspring. This is how MRSAdeveloped
Bacteria
Antibiotic
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Using PainkillersPainkillers can be used to treat the symptoms of
disease but do not kill the pathogen causing it
Paracetamol
Aspirin
Ibuprofen
http://www.mypharmacy.co.uk/medicines/medicines/a/anadin/anadin.htm7/30/2019 Science Human Biology year 10
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Ignaz Semmelweiss1818-1865
Guten tag. My name is Ignaz
Semmelweiss. In the mid-19th century Irealised that many deaths in hospitalscould be avoided by insisting on clean
hands and equipment. As a result of my
work, deaths in my wards fell from 12%to 1%.
/ /
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Experiments about the spreadof infection
Year Amount of hand washsolution used (litres per
1000 patient days)
MRSA infections per100 patients
1993 3.5 0.50
1995 6.9 0.481997 10.9 0.25
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These results show that using hand wash
solution regularly reduces the numbers ofinfections from superbugs in hospitals: thepathogens are destroyed
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Defending the bodyfrom disease
25/05/2013P th
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25/05/2013PathogensPathogens are things that cause disease.
There are two main types 2. ________1.__________
Damage cells by ___________
Killed by ________
Examples:
Damage cells by .......
Not affected by________
Examples:
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Pathogens:our defence against themOur bodies have four major defence mechanisms against invading microbes:
If our skin is
cut ______seal thewound byclotting
The breathingorgans produce
_____ to cover thelining of theseorgans and trap the
________
The _____
acts as abarrier
Our blood contains______ bloodcells
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Fighting disease
WHITE BLOOD CELLS:
White blood cells do 3 things:
1) They eat the _________
2) They produce A_________ tofight the pathogen
3) The produce __________ to
neutralise the poisons producedby pathogens
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Producing antibodies
Step 1: The white blood cell seesthe _________
Step 2: The cell produces________ to fit the pathogen
Step 3: The antibodies fit onto the
_______ and cause them to clump
Step 4: The pathogens are
eaten by the ____ ____ __
Youre goingdown
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Vaccines
A small amount of the ______ isgiven to the person
The person makes specific ________ The antibodies kill the ______
The _______ which makes the_______ stays in the blood forever
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b
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Using AntibioticsAntibiotics can be used to kill bacteria but....
1) Bacteria can become_______ to them so they
do not work anymore (e.g.______- a superbug)
2) Antibiotics do not kill______
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b
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Antibiotic resistanceBacteria can change (mutate) to become resistant to
antibiotics
1) V______ some strains of bacteriaare resistant and some arent.
2) C______ The non-resistantbacteria are killed by the antibiotic.
3) Survival of the fittest theresistant bacteria survive.
4) Passing on of _____ the resistantbacteria reproduce and pass ontheir resistance genes to their
offspring.
Bacteria
Antibiotic
E i t b t th d25/05/2013
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Experiments about the spreadof infection
Year Amount of hand washsolution used (litres per
1000 patient days)
MRSA infections per100 patients
1993 3.5 0.50
1995 6.9 0.481997 10.9 0.25
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What do these results show about how the
use of hand wash is related to the spreadof infection?
Who carried out initial experiments on
this?
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Defending the bodyfrom disease
25/05/2013P th ns
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25/05/2013PathogensPathogens are things that cause disease.There are two main types
VirusesBacteria
What do you know aboutbacteria? What do you know about
viruses?
Mi b d f i h
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Microbes: our defence against themOur bodies have four major defence mechanisms against invading microbes:
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Fi hti di
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Fighting disease
If a pathogen enters our body, white
blood cells do three things to fightit....
1.
2.
3.
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P d i
tib di
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Producing antibodies
Step : The white blood cell sees
the pathogen (microbe)
Step : The cell producesantibodies to fit the pathogen Step : The antibodies fit onto thepathogens and cause them to clump
Step : The pathogens are
eaten by the white blood cells
Put these steps
in order..
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U i A tibi ti
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Using AntibioticsGive 2 problems associated with the use of
antibiotics
1)
2)
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A tibi ti
i t
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Antibiotic resistanceBacteria can change (mutate) to become resistant to
antibiotics
1) Variation
2) Competition
3) Survival of the fittest
4) Passing on of genes
Give an example of a disease which hasevolved this way
Bacteria
Antibiotic
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5/ 5/ 3
Ignaz Semmelweiss1818-1865
What experiments did I do?
What did I find out?
How has this changed things inhospitals?
Experiments about the spread25/05/2013
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Experiments about the spreadof infection
Year Amount of hand washsolution used (litres per
1000 patient days)
MRSA infections per100 patients
1993 3.5 0.50
1995 6.9 0.481997 10.9 0.25
What is the Independent variable?
What is the Dependant variable?
Write a conclusion for these results
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Vaccines
Describe how a vaccine works...
Give one advantage and onedisadvantage of vaccines...