Disease Flashcards
what is a pathogen?
a micro organism that causes disease
what is a vector?
a living factor that transmits the disease
what is an epidemic?
when a communicable disease spreads rapidly to a lot of people at a local or national level
what is a communicable disease?
diseases that can be passed from one organism to another, of the same or different species
what is a fomite?
non-living objects that transmit disease
what are some examples of bacterial diseases?
- TB
- bacterial meningitis
- ring rot
what are the symptoms of TB?
- chest pain
- coughing up blood
- back pain
- abdominal pain
- headaches
- weight loss
- ashy skin
what is a treatment of TB?
antibiotics- long course (9 months)
what is the economic impact of TB?
1% of the world is infected each year
list 4 medical factors that have led to the decline of TB and its severity?
- vaccine development
- x-rays
- antibiotics
- better overall health
list 3 social factors that have led to the decline of TB and its severity?
- better housing
- less overcrowding
- airier and light working conditions
why might it be difficult to vaccinate a wild population?
you will never be able to find them all or track their offspring
what are the symptoms of bacterial meningitis?
- irritable
- vomiting
- abnormal reflexes
- hearing loss
- seizures
- fever
- blotchy rash
how is bacterial meningitis transmitted?
direct contact
how is TB transmited?
carried in the air- droplet infection, cattle, badgers
what are some treatments of bacterial meningitis?
antibiotics, vaccination
what is the economic impact of bacterial meningitis?
10% of people who get it will die
what are some symptoms of ringrot?
damaged leaves, tubers or stems
how is ringrot transmitted?
- infected seed tubers
- handling
- direct contact
what is the treatment of ringrot?
- no cure- leave field empty for 2 years
what is the economic impact of ringrot?
- lose a lo0t of money from no crops for 2 years
what are some examples of viral diseases?
- HIV/AIDS
- influenza
- tobacco mosaic virus
what are the symptoms of HIV/AIDS?
- flu
- TB
how is HIV/AIDS transmitted?
- direct contact of bodily fluids
- sometimes through placenta
what is the treatment of HIV/AIDS?
- retroviral drugs
- no vaccine
what is the economic impact of HIV/AIDS?
in 2021, 38.4 mil with HIV and 650,000 died
what is the difference between HIV and AIDS?
HIV attacks the immune system and so it allows AIDS to develop
what are opportunistic diseases?
disease that infects you if you have a suppressed immune system
what are some symptoms of influenza?
- coughing
- sneezing
- fever
- bad digestive system
- headaches
how is influenza transmitted?
- vaccinations
- antivirals
what is the economic impact of influenza?
- can be fatal
- long periods of time away from work
- in birds or swine flu it can effect farmers
what are some symptoms of the tobacco mosaic virus?
- leaves
- flowers and fruits damaged
- stunts growth
- crop loss
how is the tobacco mosaic virus transmitted?
- direct contact (leaves toughing)
- indirect (workers-hands/tools)
what is the treatment for the tobacco mosaic virus?
- no cure- remove crops, can buy resistant crops
what are some economic impacts of the tobacco mosaic virus?
- crop loss- lose money from lack of crops
what are some protoctista diseases?
- malaria
- potato/tomato late blight
what are some symptoms of malaria?
- anaemic
- tired
- pain
- headaches
- chills
- vomitting
how is malaria transmitted?
mosquitoes
what are some treatments of malaria?
- can’t get rid of it
- antimalaria drugs
- insect repellent
- insect net
what are some economic impacts of malaria?
in 2012, 627,000 deaths
what are some symptoms of potato/tomato late blight?
- hyphae- tiny threads of disease- penetrates leaves, tubers and fruits
what is the transmission of potato/tomato late blight?
spores spread by the wind
what are the treatments of potato/tomato late blight?
- no treatment- chemicals to prevent
what is the economic impact of potato/tomato late blight?
millions of pounds of damage each year
what are some fungal diseases?
- black sigatoka
- ring worm
- athletes foot
what are some symptoms of black sigatoka?
hyphae growing through leaves and fruit turn black
how is black sigatoka transmitted?
water and wind born spores
what is the treatment for black sigatoka?
no cure- chemical preventatives
what is the economic impact of black sigatoka?
50% reduction in yield
what are the symptoms of ringworm?
- in cattle- grey circular areas of dry skin
- humans- red, itchy circles
how is ringworm transmitted?
- direct contact
- fomites
what is the treatment of ring worm?
anti fungal cream
what are the symptoms of athletes foot?
cracking, scaling, itching or sore skin
how is athletes foot transmitted?
- fomites
- direct contact
what is the treatment for athletes foot?
anti fungal cream
what are monoclonal antibodies?
an antibody produced from a cell lineage made by cloning a unique WBC
how do clonal antibodies work?
they work by triggering the immune system and helping it to attack cancer
how do they detect plant diseases?
if the pathogens antigens are present in the plant tissue when the monoclonal antibody sticks to it
what are the types of pathogen?
- bacteria
- fungi
- viruses
- protoctista
what do pathogens have to do to cause disease?
- travel from host to host
- get into tissues
- reproduce
- cause damage
what are the different shapes of bacteria?
- cocci
- spirillum
- virbio
- bacilli
why can the shape cocci live in drier environments?
it has less surface area per volume than others
what shape is the shape spirillum?
spiral cells
how does spirillum meet less resistance in surrounding water?
it move with a corkscrew motion
why is it important that bacilli and vibrio have a greater surface area to volume ration?
it means they can take up nutrients from dilute solutions more effectively
what colour does gram negative bacteria appear under a light microscope, what stain is used and give an example?
- red
- stained with safranin
- E.Coli
what colour does gram positive bacteria appear under a light microscope, what stain is used and give an example?
- purple/blue
- crystal violet
- MRSA
how often can bacteria divide?
one bacteria can divide into 2 new ones every 20 minutes
how do bacteria cause disease?
they produce toxins and cause symptoms by cell damage. they damage ell membranes, enzymes or genetic material
what is the structure of viruses?
- some genetic material is surrounded by a protein shell
- they are non-living as they cannot replicate by themselves
what is a bacteriophage?
a virus that infects bacterial cells
what is the process of viral reproduction?
1) virus attaches to a specific host cell
2) genetic material from virus is injected into the host cell
3) the viral genes cause the host cell to make new viruses
4) the host cell splits open, releasing the new virus
protists are p______?
parasitic
what do many protoctists need to transfer them to their host?
a vector
what is disease?
any disorder or malfunction of the mind or body that leads away from good health
what is health?
the complete state of social, emotional or physical wellbeing, not just the absence of disease
what do you need to be in good health?
in good mental or physical health
what is an infectious disease?
disease that can be transmitted between organisms
label of bacterial cell on IRL flashy
label of fungal cell of IRL flashy
what does bacteria cause?
cause disease by damaging cells or replacing toxic waste products
where do some fungi live and what do they send out?
some live in the skin and send out hyphae to the surface
what do viruses do?
invade cells and take over the genetic machinery, the cells then replicate the virus until it bursts
what are protoctista?
organisms that cause harm by entering the cells and feeding on the contents
what is inoculation?
pathogens entering through a break in the skin (sex), animal bites (rabies) or sharing needles
how does ingestion cause disease?
taking in contaminated food or drink or transferring pathogens from the hands to the mouth
what are some ways disease can be transmitted through indirect contact?
- water
- vectors
- droplet infection
- fomites
how do fomites transmit disease?
inanimate objects such as bedding, socks and cosmetics transfer pathogens
how do droplet infections work?
droplets of saliva or mucus are expelled from your mouth as you cough or sneeze. healthy individuals can then breathe these in
how to vectors transmit disease?
transmit communicable pathogens from one host to another, often animals
how can water transmit disease?
can also be a vector
what are the three key factors to reduce the spread of disease in humans?
- hand washing
- improvements in living and working conditions- reduce overcrowding and ensure good nutrition
- disposal of bodily and household waste effectively
what are some factors affecting transmission in animals?
- overcrowded living and working conditions
- poor nutrition
- poor disposal of waste
- climate change
what are some examples of transmission between animals?
bird flu and brucellosis
how can transmission between animals be minimised?
- reducing close contact with animals
- washing hands thoroughly
what is direct transmission?
when the pathogen is directly transferred from one individual to another
what is indirect transmission?
when pathogens travel from one individual to another indirectly
why is it important to understand how pathogens are transmitted?
to work out ways to reduce and prevent transmission- strategic planning
what are the key factors to reduce the spread of disease in plants?
- leave room between plants
- clear fields as thoroughly as possible after harvesting
- rotate crops
- strict hygiene practices
- control insect vectors
what are factors that affect transmission in plants?
- planting a variety of crops that are susceptible
- overcrowding increases touching
- poor mineral transmission
- damp and warm conditions
what are some primary defences in a plant?
- cellulose cell wall
- waxy cuticle
- bark
what do plants do instead of healing diseased tissue?
they seal it off and sacrifice it
where do plants grow from and why?
from the meristem so they can replace damage
what are the different types of meristem?
- apical
- lateral
what does an apical meristem do?
causes primary growth
where is the apical meristem found?
tips of shoots and roots
what does the lateral meristem do?
causes secondary growth
where is the lateral meristem found?
at the cambium
how do plants recognise an attack?
- receptors respond to molecules from pathogens or chemicals released that attack the cell wall
- the cells will then release signalling molecules
what do signalling molecules do in the plant when an attack is recognised?
they switch on genes in the nucleus which triggers cellular responses such as producing chemicals, sending alarm signals and strengthening the cell wall
what do polysaccharides do in response to an attack in a plant?
increase synthesis of callose and lignin
where is callose deposited and what does it do in an attack of the plant?
in the plasmodesmata between the cell wall and membrane in cells next to the infected cells, making it harder for the invading pathogen to spread
what does lignin do in an attack of a plant?
makes the mechanical barrier even stronger
what does callose do in an attack of the plant?
blocks the sieve plates of the phloem, sealing off infection and preventing spread
why do plants produce chemicals?
to either repel insect vectors or to kill invading pathogens
why are some chemicals extracted from plants?
for insecticides, fungicides etc
what linkages does callose have?
beta 1-3 and beta 1-6 linkages between the glucose monomers that are important in the plant response to infection
is callose made up of alpha or beta glucose?
beta
what is the purpose of callose being initially synthesised and deposited between the cell wall and cell membrane next to infected cells?
the callose papillae act as a barrier, preventing the pathogens entering the plant cells around the site of infection
what is a retrovirus?
a virus that contains RNA and not DNA
what is an antigen?
an identifying chemical on the surface of a cell hat triggers an immune response
what are antibodies?
y shaped glycoproteins made by B-cells of the immune system in response to the presence of an antigen
what is an immune response?
a biological response that protects the body by recognising and responding to antigens and by destroying substances carrying non-self antigens
what is the definition of immune?
totally or partially resistant to a particular infectious disease or pathogen
what are the two types of WBC’s?
- lymphocyte
- phagocyte
what are the types of lymphocyte?
- B lymphocyte
- T lymphocyte
what are the type of B lymphocytes?
- plasma cells
- B memory cells
- B effector
what are the types of T lymphocytes?
- T helper cells (most helpful)
- T memory cells
- T killer cells
- T regulatory cells
what are the types of phagocytes?
- neutrophils
- macrophages
what are neutrophils?
- smaller
- 60% of all WBC’s
- short lived
- multi lobed nucleus
- attracted to histamines
what are macrophages?
- larger
- involved in antigen presentation
- more complex and slower process
- round nucleus
- cut up pathogen to produce antigen presenting cell
what is phagocytosis?
the ingestion of bacteria and other material by phagocytes
what is primary defences?
barriers to prevent pathogens entering- non specific
what are some examples of primary defences?
- expulsive reflexes- coughing, sneezing, diarrhoea
- nasal cavity- hairs and mucus
- stomach- acid
- ear- cerumen inhibits bacteria
- skin- impervious barrier
- eyes- cleansed by tears which contain chemicals
what are the primary repsonses?
- blood clotting
- inflammatory response
- fever
- phagocytes
- neutrophil phagocytosis
- macrophage phagocytosis
- cytokines
- opsonin
what is the process of blood clotting?
- platelets come into contact with collagen in the skin or walls of the damaged blood vessels and adhere to it
- they secrete two important substances:
- thromboplastin- enzyme that catalyses the cascade of reactions
- serotonin- causes blood vessels to contract reducing blood supply to the area
what does inflammation cause?
heat, pain, redness and swelling of the tissue (localised)
what is the process of inflammatory response?
- mast cells (a type of WBC) are activated in response to pathogens/allergens/irritants
- once activated they release the chemicals histamine and cytokines
where are mast cells found?
found in mucosal surfaces on the gut and lung, in the skin and around blood vessels
what do histamines do?
- cause blood vessels to dilate and become more permeable causing localised heat and redness
- blood vessel walls become more permeable so more blood plasma is forced out which causes swelling (odema) and pain
what do cytokines do?
attract WBC’s (phagocytes) to the site which dispose of pathogens and phagocytosis
what happens when you have a fever?
- normal body temperature is maintained by the hypothalamus in the brain (processing centre of homeostasis)
- pathogens reproduce optimally at or below this temp
- pathogens trigger cytokines to signal your hypothalamus to increase your body temp
- this inhibits pathogen reproduction
what are phagocytes?
specialised WBC’s that build up at the site of infection and engulf and destroy pathogens
what is the process of neutrophil phagocytosis?
1) pathogen is tagged with opsonin
2) it is engulfed into a phagosome
3) lysosomes contain hydrolytic enzymes
4) phagosome fuses with lysosome to make a phagolysosome
5) pathogen is then digested partially
6) phagolysosome fuses with cell membrane
7) pathogen is expelled with exocytosis
what is the process of macrophage phagocytosis?
1) pathogen is tagged with opsonin
2) it is engulfed into a phagosome
3) lysosomes contain hydrolytic enzymes
4) phagosome fuses with lysosome to make a phagolysosome
5) pathogen is then digested partially
6) the antigens are combined with glycoproteins to make major histocompatibility complex (MHC)
7) the antigen MHC is presented on the cell surface by antigen presenting cells (APC)
what are cytokines?
cell signalling molecules
what do cytokines do?
inform other phagocytes when there is a pathogen present
what can cytokines do?
- increase body temp
- stimulate the specific immune response
what do opsonins do?
bind to pathogens and tag them so they can be easily recognised by phagocytes
what are lymphocytes?
specialised WBC’s that are involved in the specific immune response
where do lymphocytes originate from?
- bone marrow
- specialised cells are derived from haematopoietic stem cells
- T cells mature in the thymus gland
what is clonal selection?
the theory that exposure to a specific antigen selectively stimulates the proliferation of the cell with the appropriate antibody
what is clonal expansion?
used whenever the cells are replicating by mitosis
what is cell mediated immunity?
the immune response mediated by activating T helper cells
what can mediated immunity lead to?
the other B and T cells being activated and propagated
what are interkleukins?
the name given to cytokines made in cell mediated immunity
what do T helper cells do?
- trigger the specific immune response by producing interleukins
- bind to the specific antigen on the surface of an APC (macrophage)
what do T helper cells have on their cell membrane?
CD4 receptors
what is the causal agent agent for malaria?
Plasmodium
what is the causal agent for athletes foot?
Trichophyton
what do B memory cells do?
- immunological memory
- 2nd infection of that pathogen
- differentiation to specific B cells
what do B effector cells do?
differentiate into B effector and plasma cells
what do plasma cells do?
produce specific antibodies to the antigen
what do T memory cells do?
- immunological memory
- produce T cells
what do T killer cells do?
- produce a chemical called perphorin to make a hole in the cell membrane
- they inject it with H2O2
what do T regulator cells do?
- regulate the immune system by suppression once the pathogen has gone
- recognises self pathogens
- prevents autoimmune response
what is the humoral response?
- B cells are associated with the humoral response
- they are activated by the T cells
- this is the response associated with circulating antibodies
what will the antibodies do in the humoral response?
they will bind to any foreign antigen they find, this could be on a pathogen or on a body cell that has become an antigen presenting cell
what are the main cells involved in humoral immunity?
B cells
what are the main cells involved in cell mediated immunity ?
T helper
where do T helper cells develop?
thymus
are antibodies involved in humoral immunity?
yes
are antibodies involved in cell mediated immunity?
no
how are pathogens identified in humoral immunity?
they have antibodies specific to antigens
how are pathogens identified in cell mediated immunity?
they are presented on macrophage APC
how are pathogens killed in humoral immunity?
either engulfed to become B cell APC’s or antibodies disable them
how are pathogens killed in cell mediated immunity?
T helper cells trigger T killer cells, plasma cells and macrophages
how do cells divide once they are stimulated in humoral immunity?
clonal expansion
how do cells divide once they are stimulated in cell mediated immunity?
mitosis
how are antibodies produced?
by plasma cells
what is the role of antibodies?
1) - antibody of the antigen/antibody complex
- acts as opsonin
- attracts phagocytes so it is engulfed
2) stops pathogens from entering host cells
3) causes pathogens to clump together prevents replication therefor prevents spread
4) - antibodies can act as anti-toxins
- binds to the toxin and makes it harmless
what is an autoimmune disease?
a condition or illness that results from an autoimmune response
when does an autoimmune response occur?
when the immune system acts against its own cells and destroys healthy tissues in the body
why are immunosuppression drugs not a good treatment?
it could also supress the normal immune system
how do autoimmune diseases occur?
it is not fully understood but tends to be genetic
what is the cure for Rheumatoid arthritis?
no cure- only can treat it with anti-inflammatory drugs, steroids, pain relief or immunosuppression
what is Rheumatoid arthritis?
a chronic progressive disease, causing inflammation in the joints and resulting in painful deformity and immobility, especially in the fingers, wrists, feet and ankles
what is Lupus?
a complex and poorly misunderstood condition that effects many parts of the body, ranging from mild to life threatening
