Immune and Disease Flashcards
State the definition of disease
-impairs normal function of an organisim
state the definition of a pathogen
a microorganisms that causes disease
what diseases are caused by bacteria
- bacterial meningitis
- tuberculosis (TB)
- Ring rot potato
what diseases are caused by fungi
- Athletes foot
- Ringworm
- Black sigatoka
what diseases are caused by virus
- HIV
- Influenza
- Tobacco mosaic virus
what diseases are caused by Protista
- Malaria
- Tomato late blight
How can diseases be transmitted directly
- Direct contact (kissing, touching)
- inoculation (makeup brushes, needles)
- Ingestion
- droplet infection
How can diseases be transmitted indirectly
- Fomites
- Vectors
- spores
What factors can affect transmission
Living conditions
-Overcrowding can increase transmission of disease
Example is TB, spread through droplet infection
Social Factors
- such as income, occupation and area
- sometimes can be hard to access good healthcare (people may be less likely to get diagnosed, treatment may be hard to obtain etc)
- good health education (telling people how certain diseases can spread and how to avoid that
Climate
- Potato late blight is common during wet summers because spores need water to spread
- Malaria spreads in hot humid conditions because this ideal for mosquitoes to bread
How does the skin act as a primary defence mechanism
- Physical barrier
- main primary defence
- Dead skin cells act as a barrier
- secrete lysozymes which catalyses breakdown of bacterial cell walls
- can secrete fatty acids that can kill bacteria and also lower pH of skin to make conditions unfavourable
How do mucus membranes act as a primary defence mechanism
- Protect openings that are exposed to environment (mouth, nostrils, ears etc)
- Cilliated cells waft mucus up your airway to be swallowed
- goblet cells secrete mucus which traps microorganisms and contains phagocytes and lysozymes
What is an expulsive reflex and how do they act as a primary defence mechanism
- Coughing and sneezing, same with vomitting and diahorea
- help expel pathogen from body
How does blood clotting and wound repair work
- Blood clots because skin is broken
- The platlets then interact with the collagen to make a blood clot
- collagen secretes thromoplastin and sertanonin to help blood clot and reduce blood flow
- clot dries scab forms
Wound repair
- epitheli cells below the scab start to grow, collagen fibres deposited to give new tissue strength
- skin grows and scabs shrinks, edges of laceration are pulled together
- if there are too many collagen fibres you end up with scar
How does blood clotting and wound repair work
- Blood clots because skin is broken
- The platlets then interact with the collagen to make a blood clot
- collagen secretes thromoplastin and sertanonin to help blood clot and reduce blood flow
- clot dries scab forms
Wound repair
- epitheli cells below the scab start to grow, collagen fibres deposited to give new tissue strength
- skin grows and scabs shrinks, edges of laceration are pulled together
- if there are too many collagen fibres you end up with scar
How does inflammation work
- mast cells activate histamines and cytokines
- histamines make blood vessles dilate, which causes heat and redness. High temp means pathogen can’t reproduce
- also blood walls are more leaky, which increases perembality so tissue fluid leakes out causing swelling (odema) which isolates any pathogens
What primary defences do plants have
Physical
- waxy cuticle provides barrier against pathogens. Also stops water collecting on leaf which reduces risk of infection as water is a vector
- Surrounded by cell wall
- proudce callose which is deposited between plant cell walls and plasma membrane when pathogen enters
- callose deposition at plasdostmta limits the pathogen from travelling into neighbouring cells
Chemical
- Saponins which can destroy cell membranes of fungi
- phytoalexins which inhibit growth of fungi
also there chemicals can be secreted to stop insects
Outline how phagocytosis occurs
- recognises there is a foreign body in cell
- Opsonins highlight pathogens and cytokines alert neutrophills
the process
- cytoplasm of neutrophill/macrophage moves around pathogen to engluf it
- Pathogen is now in a phagosome
- this fuses with a lysosome to make a phagolysosome (the hydrolytic enzyme breaks down pathogen)
In a macrophage
-It will present the pathogens on cell surface membrane to act as an antigen presenting cell (APC)
How does the immune response work
APC goes to find the t-cell with a complimentary receptor to the antigen
- this is called clonal selection
- then clonal expansion happens through mitosis
- t-helper cells activate b-lympocytes and t-killer cells
- this activates t-killer cells which an destroy pathogen by attaching to cell taken over by a virus
- t-regulatory cells which suppress immune response from there wbc
What happens during B-lymphocyte activation
- T helper cells activates b lymphcytes by releasing interleukins
- clonal selection happens where b lymphocyte with antibodies is selected
- b lymphocytes contain antibodies, which can form an antibody-antigen complex
- correct b lymphocyte divides into plasma cells and memory cells by clonal expansion via mitosis
What do plasma cells produce
Opsinins
antitoxins
antibodies
What is the structure of an antibody
antibody is a glycoprotein
-made from 4 polypeptide chains 2 light two dark
It has a
-variable region: antigen binding site, shape is complimentary to antigen
-constant region: same in antibodies but the function is it allows for phagocytes to bind
-hinge region:allows for flexibility when binding to antigen
-
What is the structure of an antibody
antibody is a glycoprotein
-made from 4 polypeptide chains 2 light two dark
It has a
- variable region: antigen binding site, shape is complimentary to antigen
- constant region: allows binding of receptors on immune cells, reigon is same in all antibodies (made up of same sequence of amino acids)
- hinge region: allows for flexibility when binding to antigen
- Disulfide bridge: holds polypeptide chain together
What is the structure of an antibody
antibody is a glycoprotein
-made from 4 polypeptide chains 2 light two dark
It has a
-variable region: antigen binding site, shape is complimentary to antigen
-constant region: allows binding of receptors on immune cells, reigon is same in all antibodies (made up of same sequence of amino acids)
-hinge region:allows for flexibility when binding to antigen
-
What are the roles of antibodies
- Aggultination
- this is when pathogens can clump together, to make it easier for phagocytes to engulf it - Neutralsing toxins
- antitoxins can bind onto toxins from pathogens. This prevents it from affecting human cells - Act as opsinins
- highlight pathogens to make them more visible to phagocytes
What is the primary immune response
- This is when the antigen activates the immune system
- Humoural and cell mediated
- Primary response is slow due to clonal selection and expansation (not enough b lymphocytes that can make antibodies needed)
- can cause symptoms
What is the role of t memory cells
remember specific antigen and can recognise it the 2nd time
What is the role of b memory cells
records specfic antibodies needed to bind onto antigens
What is the secondary immune system
- if the same pathogen enters immune response will be quicker and stronger
- clonal selection is faster
- memory b cells can divide into plasma cells
- memory t cells are activated ( divide into t lymphocytes to kill the pathogen)
- secondary immune system gets rid of pathogen before symptoms
Why does immunity not last forever
- memory b and t cells have a limited lifespan
- when they die, a person may be susceptible to attacks again
- Immunity can be maintained by being continually exposed to pathogen so you make more b and t memory cells
What is active immunity
type of immunity where your body makes its own antibodies after being stimualted by antigen
What are the two types of active immunity and give an example
Natrual :immune after having the disease (e.g after getting measles as a child and getting it again)
Artifical:become Immune after a vaccine
What is passive immunity
Immunity obtained from being given antibodies made from another organism
so its not your own antibodies
What are two types of passive immunity and give examples
Natural: when baby becomes immune due to antibodies it receives from mother (from breastmilk)
Artificial: when you become immune from being injected with somebody else antibodies (e.g if you get tetanus your injected with antibodies from blood donations)
Can you compare passive and active immunity
- active immunity requires exposure to antigen but passive doesn’t
- for passive immunity protection is immediate but for active it takes some time
- active immunity protection is long term whereas in passive it’s short term
- in active immunity memory cells are produced but not in passive immunity
What does an autoimmune disease do
It attacks the bodies own cells
Give examples of autoimmune diseases
Lupus: autoimmune disease that attacks connective tissues, damage causes painful inflammation. Lupus can affect skin, joints, hearts and lungs
Rheumatoid arthritis: when immune system attacks cells the joints, causes inflammation and pain.
Type 1 diabetes
How can you get a vaccine into your body
What do vaccines contain
- they can be taken injected or taken orally
- Vaccines contain antigens that can cause an immune response
- the antigens can be weakened, isolated, free, or attached
What is the disadvantage of taking vaccines orally
- can be broken down by enzymes in the gut
- or the vaccine can be too large to absorb into blood
What is herd immunity
when unvaccinated people are protected against the vaccine due to the occurrence of disease is reduced by vaccinated people
What routine vaccines do we take
the MMR vaccine: taken around 1-year-olds, contains attenuated (weakened) measles, mumps and rubella
the meningitis c vaccine: given at 3 months and at 1 year
Why are new vaccines developed every year
The influenza virus can change the antigens on its surface
so every year there is a new vaccine made
-their effectiveness is tested by WHO and the CDC
-the one that’s chosen is most effective against that years influenza
What is an antibiotic
chemicals that inhibit and kill bacteria
Who discovered antibiotics and what was the name of the antibiotic
Alexander Fleming
Penacilin
What are the risks of antibiotics
- side affects
- can cause severe allergic reactions
- antibiotic resistance
When did antibiotic resistance become widespread
mid-twentieth century
Give two examples of bacteria resistant to antibiotics
MRSA: causes serious wound infections, resistance to methicillin
Clostridium difficile: affects digestion system, produces toxins which cause diarrhoea
How can you prevent antibiotic resistance
-doctors encourage to reduce use of antibiotics only give it when needed not as a prevention
-patients advised to take full course of antibiotics to kill all bacteria
-
What is synthetic biology
involves technology to design and make artificial proteins, cells and microorganisms
for example scientist that engineer bacteria destroy cancer cells whilst leaving healthy body cells intact
What is personalised medicine
medicines that are tailored to one’s DNA
the theory is we can use it to predict how we will respond to different medicines
help only to prescribe ones that will work for you
