Disease, defence and treatment Flashcards
(24 cards)
What is a pathogen?
A pathogen is a mirco-organism that causes disease
Which 4 forms can pathogens come in?
- bacteria
- viruses
- fungi
- protists (single-celled)
Describe the structure of a bacterium cell
- cell membrane
- cell wall
- cytoplasm
- free strand of DNA (no nucleus)
- plasmids
Describe the structure of a viral cell
- genes
- protein coat
How are pathogens spread?
- contact
- aerosol
- insects
- water
- contaminated food
- bodily fluids
How does the skin defend against pathogens?
The skin is a waterproof layer that forms a barrier around the body to stop microbes from getting in. It also has a community of micro-organisms (skin flora) living on it which outcompete pathogens on the skin’s surface
How do platelets defend against pathogens?
Platelets stops pathogens form getting in through cuts by forming blood clots around open wounds, which harden to form scabs
How do phagocytes defend against pathogens?
Phagocytes are white blood cells that engulf and digest foreign microbes in the body through phagocytosis.
How do lymphocytes defend against pathogens?
Lymphocytes are white blood cells that produce antibodies. Specific antibodies bind to specific antigens on the surface of the pathogen, destroying the pathogen. Lymphocytes also produce antitoxins, which neutralise specific toxins that are released by bacteria.
What is an antigen?
Antigens are molecules on the surface of pathogens that the immune system recognises as foreign.
What is a memory cell?
Lymphocytes can clone into memory cells, which recognise antigens that get into your body again. The memory cells then produce lots of antibodies very quickly, destroying the pathogen before it can make you ill.
What is a plasma cell?
Lymphocytes can clone into plasma cells, which deal with the current infection then die afterwards.
What is a vaccination?
Vaccinations introduce a small amount of dead or inactive pathogens into the body, causing memory cells to be produced and therefore making the body immune to the real pathogen.
What is the MMR vaccination?
The MMR vaccine protects against measles, mumps and rubella.
What are the influences on vaccine uptake?
- media
- side effects
- religion
- herd immunity
- peer pressure
How do antibiotics cure bacterial infections?
Antibiotics kill bacteria or stop them from growing
Where were antibiotics originally derived from?
They were originally produced by living organisms such as fungi, but are now synthetically made
How does bacteria become resistant to antibiotics?
Some bacteria (e.g. MRSA) naturally become resistant from random mutation. Use of antibiotics in animal feed and over-prescription of antibiotics from doctors is making this issue worse
How is MRSA controlled?
- handwashing
- thorough cleaning of hospital wards
- use of hand sanitiser
- MRSA screening
How can one keep their health generally well?
- good hygiene
- clean water
- good diet
- vaccination
How can other conditions be treated?
- gene therapy
- organ transplants
- radiotherapy
- chemotherapy
- drugs
What must be done before introducing new drug treatments?
Large scale, rigorous testing must be done to identify possible side effects
What are the benefits of animal testing?
- humans should not be subject to life-threatening experimental procedures
- testing on individual cell tissues does not reflect the complexity of living organisms
- computer simulations are not accurate enough
What are the disadvantages of animal testing?
- animals are so different from humans and do not react the same way to drugs
- its unethical to subject animals to experimentation
