Infection and Response Flashcards
1
Q
name the different pathogens
A
viruses, bacteria, protists and fungi
2
Q
how are pathogens spread?
A
- direct contact- can be sexual contact during intercourse or non-sexual contact, like shaking hands
- water- dirty water can transmit many diseases
- air- when an infected person sneezes, coughs etc., they can spray thousands of tiny droplets containing the pathogen to infect others.
- unhygienic food preparation- undercooked or reheated food can cause bacterial diseases like escherichia coli which is a cause of food poisoning.
- vector- any organism that can spread a disease is called a vector- any farmers think tuberculosis in their cattle can be spread by badgers
3
Q
how do pathogenic bacteria and ciruses cause damage in the body?
A
- viruses cause infections by entering and multiplying inside the host’s healthy cells
- bacteria spread diseases by producing toxins which damage human tissues and make us feel ill
- bacteria can cause disease by reproducing within the human body very quickly
4
Q
how can the spread of disease be prevented?
A
- sterilising water- e.g. cholera- chemicals or UV light kill pathogens in unclean water
- suitable hygiene (food)- e.g.salmonella- cooking foods thoroughly and preparing them in hygienic conditions kills pathogens
- suitable hygiene (personal)- e.g. athlete’s foot washing surfaces with disinfectants kills pathogens (treating existing cases of infection kills pathogens)
- vaccination- e.g. measles- vaccinations introduce a small or weakened version of a pathogen into your body, and the immune system learns how to defend itself.
- contraception- e.g. HIV/AIDs- using barrier contraception, like condoms, stops the transfer of bodily fluids and sexually transmitted diseases
5
Q
describe measles and identify what type of pathogen it is
A
- a very infectious viral disease
- often caught by young children by transmition through the air in tiny droplets after an infected person sneezes
- causes a fever and skin rash but can cause more serious effects like infertility in adults who did not catch the disease as children
- children in developed countires are given vaccines but this isn’t available everywhere
6
Q
describe HIV and identify what type of pathogen it is
A
- virus/ viral pathogen
- human immunodeficiency virus
- transmitted by body fluids, often during unprotected sex, but also through cuts and injecting drugs using shared needles
- suffer mild flu-like symptoms but these pass and infected may not realise they have it
- months or years after the infection of the HIV virus, it becomes active and starts to attack the patient’s immune system, becoming AIDS
- no cure but infected people are given antiviral drugs, which can slow the development of AIDS
7
Q
describe tobacco mosaic virus and identify what type of pathogen it is
A
- viral pathogen
- infects the chloroplasts of plant leaves and changes their colour from green to yellow or white in a mosaic pattern
- infects tobacco and other closely related species, such as tomatoes and peppers
- transmitted by contact between plants, either naturally or through the hands of farmers
- reduces the plant’s ability to photosynthesise and grow properly
- no cure
8
Q
describe salmonella and identify what type of pathogen it is
A
- bacterial pathogen
- causes food poisoning- abdominal cramps, vomiting and diarrhoea
- caused by unhygienic kitchens, undercooked foods such as meat, eggs and poultry, or the same foods that have not been reheated properly
- prevented by all poultry being vaccinated against it and cooking food thoroughly, after preparing it in hygienic conditions
9
Q
describe gonorrhea and identify what type of pathogen it is
A
- bacterial pathogen
- sexually transmitted disease- burning pain when urinating and often forms a thick yellow or green
discharge- can result in infertility - can be prevented by not engaging in sex or using contraception
- treated by antibiotics
10
Q
describe the signs, transmission and treatment of rose black spot and identify what type of pathogen it is
A
- fungal pathogen
- infects leaves and causes black or purple spots on the leaves and the rest of the leaves often turn yellow and can drop off the plant, reducing it’s ability to photosynthesise and therefore grow
- transmitted in air or water, as well as through direct contact by gardeners
- treatable using
fungicides
and by removing and destroying infected leaves
11
Q
describe symptoms, transmission and treatment of malaria and identify what type of pathogen it is
A
- protist pathogen
- spread by mosquitos which carry the plasmodium protist- suck blood containing the protists from an infected person, passing the protist to other people they suck blood from
- the mosquitos don’t become ill and are called vectors
- symptoms of malaria include a fever, sweats and chills, headaches, vomiting and
diarrhoea - no vaccination, prevented by sleeping under mosquito nets and wearing insect repellent to avoid bites, take antimalarial drugs which treat the symptoms and can prevent infection
12
Q
describe defences that stop pathogens entering the human body
A
- skin- covers almost all parts of your body, acting as a physical barrier, if it is cut it immediately heals itself and forms a scab
- nose- internal hairs, which act as a physical barrier to infection and mucus produced traps pathogens before they can enter the lungs and when the nose is blown, mucus containing pathogens is removed
- trachea/ windpipe- ciliated cells that line the trachea waft their hairs and move mucus and pathogens upwards towards the throat where it is swallowed into your stomach and gablet cells create the mucus- mucus in airways are a physical barrier
- stomach- stomach (hydrochloric) acid kills any pathogens caught in the mucus in the airways or consumed in food/ water, it is a chemical barrier
13
Q
how do white blood cells destroy pathogens?
A
- two types: phagocytes and lymphocytes
- phagocytes- attracted to and surround any pathogens in the blood and bind to and engulf them, breaking down and destroying them- phagocytosis
- lymphocytes- detect that antigens are foreign and produce antibodies which cause pathogens to stick together and make it easier for phagocytes to engulf them. they also produce antitoxins to neutralise any toxins a pathogen might release
14
Q
how does vaccination work, including at population level?
A
- they allow a dead or altered form of the disease causing pathogen to be introduced into the body which stimulates the body to produce antibodies to provide immunity against that disease
- herd immunity- the protection given to a population against an outbreak of a specific disease when a very high percentage of the population have been vaccinated against it
15
Q
explain how antibiotics and painkillers are used to treat diseases and their limitations
A
- antibiotics- substances that slow down or stop the growth of bacteria by damaging the bacterial cells but not the host cells which stops them reproducing and spreading
- one antibiotic may only work against one or a few types of bacteria meaning a range is needed, theyonly cure bacterial diseases and not viral ones
- painkillers- chemicals that relieve the symptoms but do not kill the pathogens
