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FIGHTING DISEASE, FIGHTING DISEASE- DRUGS, FIGHTING DISEASE-VACCINATION -…
FIGHTING DISEASE
YOUR BODY HAS A PRETTY SOPHISTICATED DEFENCE SYSTEM
the skin acts as a barrier to pathogens- it also secretes antimicrobial substances which kill pathogens
hair and mucus in your nose trap particles that could contain pathogens
the trachea and bronchi secrete mucus to trap pathogens
the trachea and bronchi are lined with cilia- these are hair-like structures which waft the mucus up to the back of the throat where it can be swallowed
the stomach produces hydrochloric acid. this kills the pathogens that make it that far from the mouth
YOUR IMMUNE SYSTEM CAN ATTACK PATHOGENS
If
pathogens
do make it in to your body, your system kicks in to destroy them
WBC's are the most important part in your immune system. they travel around your blood and crawl into every part of you constantly controlling for microbes.
CONSUMING THEM
WBC's can engulf foreign cells and digest them.
known as phagocytosis
they have three lines of attack
PRODUCING ANTIBODIES
every invading pathogen has unique molecules called antigens on its surface
when some WBC's come across a foreign antigen they will start producing proteins called antibodies to lock into the invading cell
so they can be found and destroyed by other white blood cells. the antibodies produced are specific to the type of antigen
antibodies are then produced rapidly and carried around the body to find similar Bacteria or virus
if a person is infected with the same pathogen again the white blood cells will rapidly reproduce the antibodies to kill it
the person is naturally immune to it and will not get ill
the white blood cells that produce antibodies are also known as B- lymphocytes
PRODUCING ANTITOXINS
These counteract toxins produced by the invading bacteria
FIGHTING DISEASE- DRUGS
SOME DRUGS JUST RELIEVE SYMPTOMS- OTHERS JUST CURE THE PROBLEM
Painkillers are drugs that relieve pain. however they don't tackle the cause of the disease or kill pathogens, they just help reduce the symptoms
other drugs do similar things- reduce the symptoms without tackling underlying cause.
antibiotics work differently they actually kill the bacteria causing problem without killing your own body cells
different antibiotics don't destroy viruses. viruses reproduce using your own body cells which make it harder to develop drugs
BACTERIA
CAN BECOME
RESISTANT
TO
ANTIBIOTICS
bacteria can mutate-
sometimes mutation causes resistance to antibiotic
if infection occurs, some bacteria may be resistant to antibiotics
individual resistant bacteria will survive and reproduce
the population of the resistant strain will increase
MRSA- methicillin- resistant staphylococcus aureus causes serious wound infection
MANY DRUGS COME FROM PLANTS
Plants produce a variety of chemicals to defend themselves from pest and pathogens
some of the drugs are used as to treat human diseases
or relieve symptoms
current medicines were discovered by studying plants used in traditional cures
aspirin used as painkiller and lower fever- developed from chem found in willow
digitalis used to treat heart conditions-chem in foxgloves
3 main stages in drug testing
in preclinical testing drugs are tested on human cells and tissues in the lab
but you can't use human cells and tissues to test drugs that affect the whole body or multiple body systems
FIGHTING DISEASE-VACCINATION
VACCINATION-PROTECTS FROM FUTURE INFECTIONS
When you're infected with a new pathogen, it takes your WBC's a few days to learn how to deal with it.
by this time you can become very ill
vaccinations involve injecting small amounts of dead or inactive pathogens. these carry antigens which cause body to produce antibodies to attack them
the MMR vaccine contains weakened versions of the virus that cause measles, mumps and rubella, all in one vaccine
but if live pathogens of the same type appear after that, the white blood cells can rapidly mass- produce antibodies to kill off the pathogens
PROS
Vaccines have helped control lots of communciable diseases that were once common in the UK
polio, measles,whooping cough,rubella, mumps, tetanus etc
because of vaccinations, smallpox no longer occurs at all, and polio infections have fallen by 99%
big outbreak of disease called epidemics can be prevented if a larger percentage of the population is vaccinated. that way
CONS
vaccines don't always work- sometimes they don't give you immunity
there may be chance of bad reactions to a vaccine. swelling or maybe something more serious - fevers and seizures. but bad reactions are very rare.