Communicable Diseases Flashcards
Define health
A complete mental state of physical, mental and social well-being and being free of disease
What does being healthy mean
-being active
-good diet
-free of diseases
What is a pathogen
A microorganism that causes disease
What are the 4 types of pathogen
Bacteria
Virus
Fungi
Protist
What is bacteria
Reproduces rapidly (every 20 mins)
Releases toxins making us feel ill
Give 3 examples of bacteria
Tuberculosis- (mycobacterium and m. Bovis)
~ affects many parts of the body
~kills cells and tissues - affects mostly the lungs
Meningitis -( streptococcus pneumonia)
~ infection of the meninges (membranes that surround brain and spinal cord)
~ membranes become swollen and causes nerve damage
Ring rot- in plants- (clavibacter michiganensis)
~ ring of decay in vascular tissue in tomato and potato
~ leaf wilting
What is a virus
Invades cell and burst out of them infecting healthy ones
Give 3 examples of a virus
HIV- human immunodeficiency virus
~attacks cells in immune system
Influenza- family orthomyxoviridae
~attacks respiratory system and causes headaches and muscle pain
Tobacco mosaic virus - tobacco mosaic virus
~ caused discolouration of leaves (in mosaic pattern)
What is fungi
Lives in skin of animals
Hyphae grows to surface and releases spores = red and itchy
In plants = vascular tissue
3 examples of fungi
Black Sigatoka- in bananas (mycosphaerella fiji ensis)
~ causes leaf spots on banana
-reducing yield
Ringworm (cattle) - tricophyton verrucosum
~growth of fungus in skin with spores erupting through skin to cause a rash
Athletes foot (tricophyton rub rum)
~ growth under skin of feet especially between toes
What is a protist
It enters host cell and feeds on their contents while it grows
Give 2 examples of protist
Blight (potato or tomato) - phytophthara infestans
~ affects potato tubers and leaves
Malaria - plasmodium
~ parasite in blood that causes headache and fevers
~ can progress to comas and death
What is the life cycle of a pathogen
-Transmission- travels from host to host
-enters host tissues
-reproduces
-leaves host tissues
What is DIRECT transmission between animals - physical contact and factors affecting it
-touching infected person
-contaminated surface
E.g HIV, meningitis, ringworm
Factors affecting it
-wash hands regularly
-keep surfaces clean
-use condoms
DIRECT transmission between animals - faecal-oral transmission and factors affecting this
-Usually by drinking contaminated water or eating contaminated food
E.g cholera, food poisoning
Factors affecting it;
-treatment of drinking water
-thorough washing of fresh food
DIRECT transmission- droplet infection and factors affecting it
-pathogen carried in tiny water droplets in air
E.g influenza, tuberculosis
Factors affecting this transmission
- catch it- bin it- kill it
-cover mouth when coughing or sneezing
DIRECT transmission- Transmission by spores
- carried in air
- or carried by soil or on surfaces
Factors affecting this is
- wear masks
- wash skin after contact with soil
Other factors affecting transmission - social
-Overcrowding
-poor health
-poor ventilation
Indirect transmission in animals
Vector
- pathogen uses another organism to enter primary host
give 2 Transmission ways of PLANT pathogens
-Fungi spores - carried in wind - airborne transmission
-Pathogens present in soil infects plant by roots
Indirect transmission of PLANT pathogens
Insect attack - insects attack infected plant then attacks another plant
What do Passive defences include
Physical barriers and chemicals
Give examples of physical defences
- cellulose cell wall- physical barrier and has lots of chemicals
-callose- in sieve tubes- blocks flow so can stop pathogen spreading
-stomatal closure- when pathogen is detected guard cell closes stomata
Chemical defences
-Menthols - produced by mint- which is an e.g of terpenoids (oils with antibacterial properties)
-Alkaloids such as caffeine and morphine which is bitter prevents herbivores eating them
-phenols such as tannin interfere with digestion thus inhibiting insects from attacking the plant
Primary defences are non specific, what is non specific defences
Prevent entry of any pathogen
What are the primary defences (skin)
Skin
-acts as physical barrier blocking pathogens from entry
-also acts as a chemical barrier
Another defence (mucous membranes)
-Secrete mucous to trap pathogens
-contains anti microbial enzymes
Blood clotting
-plug wounds to stop entry of pathogens
-platelets are exposed to damaged blood vessels
-clot prevents bleeding
-also forms a scab
Inflammation
-swelling, pain and heat
-by tissue damage- releases molecules and starts to leak fluid (swelling)
-molecules cause vasodilation increasing blood flow to area and brings white blood cells
Expulsive reflexes
-Sneezing and coughing
-mucous membranes are irritated in nostrils
-sneezing/coughing is an attempt to get rid of foreign objects
Wound repair
Skin repairs itself in injuries
-uses collagen to repair
-surface is repaired by layer of skin dividing
What are antigens
-Molecules on the surface of cells
-when a pathogen enters the body the antigen on it is foreign so it initiates a body response
Fill in the gaps
1.Immune system involves - - - and - - - stages
2.The specific response is - - - aimed at specific pathogens
3.it involves white blood cells called - - - and - - - lymphocytes
1.Specific and non specific
2.Antigen specific
3. T and B
Stage 1: Steps of phagocytosis
-phagocyte recognises the antigens on a pathogen
-phagocyte engulfs the pathogens (made easier by opsonins)
-it is now contained in a phagosome
-lysosome fuses either the phagosome and enzymes breakdown the pathogen
-the phagocyte then presents the pathogens antigens
~it sticks the antigens on its surface to activate other immune system cells
What is opsonins
Chemicals that bind to foreign cells making it easier for phagocytes to recognise
What is stage 2: phagocytes activating T lymphocytes
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