Fighting disease - B1a Flashcards
What barriers does the body have to protect itself from disease?
Skin, hairs, mucus, platelets (help blood to clot) and white blood cells.
How do white blood cells prevent disease spreading?
^ They can engulf foreign cells and digest them.
^ Produce Antibodies - they produce antibodies that will lock on to the antigen of invading cells and kill them. Antibodies are specific to certain antigens.
^ Memory cells - when an invading cell arrives white blood cells make a memory cell of that antigen so they can produce antibodies again quickly if it returns.
^ Produce antitoxins - to contrast toxins produced by bacteria.
How do vaccinations work?
You inject a small amount of a dead or inactive micro-organism. So you body will then produce antibodies to kill them and make a memory cell. If the disease comes back your body will remember how to kill it.
Pros and cons of vaccination
Pro - have helped to control many infectious diseases (polio, measles, mumps, rubella…)
^ Epidemics can be prevented if people are vaccinated as people won’t be able to pass it on. This saves lives.
Cons - Doesn’t always work
^ You could have a bad reaction
^ not everyone vaccinated anyway.
Do all drugs cure diseases?
No
Painkillers - relieve pain and reduce symptoms not kill the disease,
Yes - Antibiotics kill (prevent growth) of bacteria but not viruses!
Can Bacteria become resistant to antibiotic, why?
They can mutate (change shape of antibodies don’t fit) so the new strain of infection won’t be killed. They will then reproduce and survive causing a resistant strain. e.g MRSA is resistant to antibiotics.
Avoid this by not over prescribing antibiotics.
How do you test the action of antibiotics?
Grow micro-organisms in a culture - medium like agar jelly.
^ pour hot agar jelly into a petri dish (sterilised)
^ Wait for it to set then heat inoculating hoops to kill bacteria on them, then place microorganisms in jelly.
^ use paper discs to soak up different types of antibiotics. (Anti-restistant will continue to grow - non resistant will die.)
^ Dish must have sealed lid on to stop microorganisms from getting in or out.
What did Semmelweis create?
He worked in a hospital and saw many people dyeing after childbirth.
He said doctors were spreading disease through unwashed hands,so he created an antiseptic hand wash to kill bacteria on their hands. It worked and death rates fell.
It didn’t stick as bacteria was not known then and he could not proved how it worked.
Problems with over-prescription
People are more likely to get resistant strains of the disease and we cannot cure them.
New problems with bacterias
^ Can mutate and produce new strains
^ New strain resistant to antibiotics
^ People aren’t immune to disease
^ Cause epidemic
New problems with viruses
^ Can mutate often
^ Vaccination don’t work as antigens have changed.
^ Could cause deaths and a pandemic as it id VERY difficult to stop
What are the two main types of pathogen and how do the effect you?
^ Bacteria - very small - they make you feel ill by damaging your cells and producing toxins.
^ Viruses - Very very small - they replicate themselves by invading cells and use the cells machinery to produce copies of itself. The cell then bursts releasing the copied virus and this continues.
