communicable diseases Flashcards
how are infections caused
Infections are caused whenever a foreign pathogen invades an organism (animal or plant) c
what are viruses
viruses are tiny, non-living (do not contain cells) particles that can reproduce rapidly within the body.
they invade host cells and use them to make new virus particles
once the new viruses are made they cause the cells to burst and the cell damage makes us feel ill
what is bacteria
bacteria are small living cells that either damage cells directly or by producing toxins (poisons )
bacteria can reproduce rapidly in the appropriate conditions : warm, moist areas with a good supply of oxygen.
the toxins released by bacteria can damage cells and tissues making us feel ill
what is fungi
some fungi are single felled organisms that have a body made up of hyphae (thread like structures ) .
the hyphae are able to grow and penetrate tissues, such as human skin or the surface of plants
the hyphae produce spores that can spread to other plants and animals
what is a protist
protists are single-felled eukaryotic organisms (they hv a nucleus ) many are parasites, meaning that they live on or inside other organisms.
they are often transferred to the host organism by a vector , such as an insect or mosquito
they make us feel ill by damaging our tissues
how are diseases spread 3 ways
direct contact- some pathogens live on surface of other organisms such as the skin. if infected skin touches a surface , some of the pathogens can transfer from infected skin to the surface. the pathogen then spreads to other people who also touch that surface
water- some pathogens contaminate water supplies. organisms drinking this contaminated water can be infected by pathogens
air- some pathogens are released into the air inside droplets when an organisms coughs or sneezes. these droplets can then be inhaled by other organisms
how to prevent infection spread
vaccination - can make people immune (resistant to) infection. the more individuals that are vaccinated the less likely the disease is to spread
hygiene- we can destroy pathogens by being hygienic or wash them away so they are not spread
disease vectors- some protist diseases are carried by vectors , a vector is an organism that carries pathogens without being infected for example we can protect against mosquitos carrying malaria using mosquito nets
what is the name of an organism that carries pathogens without being infected
a vector
what is tobacco mosaic virus
TMV is a pathogen that affects plants such as tomatoes
the unique mosaic pattern of the discoloration of the plant stunts the growth of the affected plant because photosynthesis cannot take place
what is measles
symptoms include a fever and a red slim rash it can be fatal if complications arise
for this reason most young children are vaccinated against measles
the measles virus is spread by breathing in droplets from sneezes and cough
what is HIV
HIV is spread by sexual contact or the exchange of bodily fluids (e.g blood from sharing needles)
initially HIV causes a flu like illness. unless antiretroviral drugs are used successfully the HIV virus enters the lymph nodes and attacks the body’s own immune system
wheat are types of viral diseases
HIV measles TMV
how do HIV and aids differ
AIDS is caused by HIV it is the name given to the life threatening infections that can occur when a persons immune system has been badly damaged by HIV
what is salmonella
if food has not been cooked properly or has been prepared in unhygienic conditions then we may ingest (eat) salmonella bacteria that causes food poisoning
the bacteria real eases toxins (poisons) causing fever, stomach pain , vomiting and diarrhea
what is gonorrhea
gonorrhea is a sexually transmitted disease
it’s symptoms include pain when urinating and a sticky yellow or green discharge from virgina or penis
barrier methods of contraception such as condoms can be used to stop the bacteria spreading from person to person
what is rose black spot
rose black spot can be spread in water or in the air (wind) . it causes purple or black spots on the leaves of rose plants. eventually , the leaves discolour and fall off. this makes it harder for plants to photosynthesie and plant growth slows
removing and destroying discoloured leaves using fungicides cab treat affected plants
what is malaria
malaria is spread by the female anopheles mosquito (a vector )
if a mosquito is carrying malaria then it transfers the infection into a persons bloodstream when it bites them
malaria leads to recurring and servere fevers which can cause death
how is stomach acid a non specific defense
stomach acid- glands in the stomach wall produce hydrochloric acid which destroys any pathogens that enter the stomach
how is lucia a non specific defense
mucus is produced in the respiratory system and traps the particles and bacteria entering our airways
how is skin a non specific defense
skin is a waterproof barrier that pathogens cannot pass through
good bacteria live permanently on our skin covering the surface and preventing pathogens from growing on our skin
how are tears a non specific defense
tears contain enzymes that destroy any pathogens thag make contact with our eye
what are antitoxins
some bacteria produce toxins that can damage cells and tissues
the immune system responds to this by producing antitoxins which neutralize the toxins realeased by the bacteria and prevent them from causing harms
what is a phagocytosis
a white blood cell finds the pathogen and engulfs it by changing shape
the white blood cell ingests (absorbs) and digests the pathogen , destroying it
what are antibodies
white blood cells recognize foreign antigens (proteins ) on the surface of pathogens and produce protein molecules called antibodies
antibodies are specific to particular pathogens
