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4.3 INFECTION AND RESPONSE - Coggle Diagram
4.3 INFECTION AND RESPONSE
4.3.1 Communicable Diseases
Bacteria
Salmonella
Ingesting bacteria in contaminated food
Abdominal cramps, vomiting, diarrhoea cause by toxins secreted by bacteria
Vaccinate poultry, good food hygeine
Gonorrhoea
Sexual contact
Thick yellow/green discharge from vagina/penis, pain while urinating
Barrier method of contraception, control spread with antibiotics
Virus
Measles
Inhalation of airbourne droplets from sneezes/coughs
Fever/red skin rash
Measles vaccine as child
HIV
Sexual contact/ exchange of bodily fluid eg. blood
Initial - flu-like symptoms, attacks body's immune system becomes badly damaged so can no longer deal with other infections/cancers
Don't share needles, safe sex, controlled with antiretoviral drugs
Tobacco Mosaic Virus (TMV)
Leaf on leaf contact
Mosaic pattern on leaves which inhibits growth due to lack of photosynthesis
Destroy infected plant
Protists
Malaria
Life cycle includes mosquito which transmits person to person
Recurrent episodes of fever (fatal)
Prevent mosquitos from breeding and use nets to avoid bites
Fungi
Rose black spot
Wind or water - absorbed through roots
Purple/black spots on leaves - turn yellow and drop early, stunted growth as photosynthesis is reduced
Fungicides/removing and destroying affected plants
Pathogen
Disease
How is it transmitted?
Symptoms
Prevention
4.3.1.6 Human Defence Systems
Physical methods
Physical Barriers
Nose
Hair and mucus capture pathogens
Stomach
Hydrochloric acid kills and dissolves most ingested pathogens
Trachea
Cilia use mucus to trap and kill pathogens then mucus moved out body
Skin
Secretes oil which kills pathogens, diificult to penetrate
WHITE BLOOD CELLS
PHAGOCYTES
Phagocytosis
Engulf and digest pathogens
Fully engulf pathogen
Release digestive enzymes to destroy pathogen
LYMPHOCYTES
Make and release antibodies which bind to antigens (acts as a label so easier for phagocytes to recognise pathogens)
Divides rapidly by mitosis, allowing itself and its clones to make large numbers of complementary antibody for each antigen on pathogen
Produce antitoxins - neutralise toxins produces by bacteria and protists
4.3.1.7 Vaccines
Spread of pathogens can be reduced by immunising large proportion of population
Introduce small quantities fo dead/inactive forms of pathogen into body
Stimulates white blood cells (lymphocytes) to produce antibodies. After pathogen destroyed, lymphocytes turn into memory cells
If same pathogen re-enters the body the memory cells respond quicker and on greater scale
4.3.1.9 Discovery and development of drugs
Process of development of new medicines
Traditionally drugs extracted from plants and microorganisms
Heart drug digitalis originates from foxgloves
Painkiller aspirin originates from willow
Penicillin discovered by Alexander Fleming from Penicillium mould
Modern drugs
Synthesised by chemists in pharmaceutical industry. HOWEVER starting point may still be chemical extracted form plant
Clinical testing
New drugs extensively tested for:
Toxicity
Efficiency
Dose
Preclinical testing done in lab using cells, tissues and live animals
Clinical trials use healthy volunteers and patients
Very low dose of drug given
If drug is safe, further clinical trials carried out to find optimum dose for drug
In double blind trials, some patients given a placebo
4.3.1.8 Antibiotics and Painkillers
Use of antibiotics in other medicines in treating disease
Cure bacterial diseases by killing infective
bacteria
inside the body
Specific bacteria should be treated by specific antibiotics
Use of antibuotics reduce deaths from infectious bacterial diseases BUT emergence of resistrant strains is great concern
CANNOT
kill
viral
pathogens
Painkillers and other medicines used to treat symptoms of disease BUT
do not kill pathogens
Difficult to develop drugs without also damagin body's tissues
