Communicabke Diseases, Prevention And Immune Systems Flashcards
Name 4 groups of pathogen that can cause communicable diseases
Bacteria
Fungi
Protoctists
viruses
How does M. tuberculosis causes tuberculosis (TB) in human
The bacteria infect the lungs, causing a chronic cough and bloody mucus
It is a disease often associated with poor hygiene and sanitation
Bacteria is a type of pathogen who can they be classified
By there shape or by there cell walls
What are the two main types of bacterial cell walls
how the different structures react differently with a process called gram staining
whys it’s useful
Gram positive bacteria
- purple blue under light microscope
Gram negative bacteria
- appear red
This is useful because the type of cell wall affects how bacteria react to different antibiotics
Viruses are a type of pathogen explain there structure
Viruses are non living infectious agent
Basic structure; genetic material surrounded by proteins
How do viruses work
Viruses invade living cells where the genetic material of the virus take over the biochemistry of the host cell to make more viruses
Viruses reproduce rapidly and evolve n
By developing adaptations to their host
How do protoctists act as pathogens
They use people or animals as their host organism
Pathogenic protists may need a vector to transfer to their hosts or enter body
Structure of fungi
Eukaryotic cells have cel walls and central vacuole their bodies consists of filament known as hyphae these hyphae form a network amd spread throughout host
Different type of fungus
Saprophytes- means they feed on dead and decaying matter
Parasitic - feed on living plants and animals
What is pathogen mode of action
- damaging host tissues directly viruses
Take over cell metabolism
Genetic material gets into the host. Ell and is inserted into hiss’s DNA
Virus uses host cells to make new viruses which burst out of the cell destroying it and then spread to infect other cells
What is protoctista mode of action by damaging the host tissues directly
Some take over cells and break them open as the new generation emerge but they do not take over genetic material,
They digest and use the cell contents as they reproduce
What is fungi mode of action damaging the host tissues directly
They digest living cells and destroy them
Combines with the response of the body to the damage causes the symptoms of disease
What is bacteria mode of action by producing toxins which damage host tissues
Bacteria produce toxin that poison or damage the host cells
Some bacteria, toxins damage the host cells by breaking down cell membrane
Some damage or inactivate enzymes
some interfere with the host cell genetic material so cells cannot divide
Explain ring rot
Is a bacterial disease of potatoes, tomatoes and aubergines cause by gram positive bacterium
Damages leaves, tubers and fruit
It will destroy the crop and can’t be grow again for at least another 2 years
What is TMV and what does it do to the plants
Is a virus
It damages leaves,flowers and fruit
It sunstroke growth and reduces yields and can lead to total crop loss
Method of transmission is lead to leaf contact or humans touching different plants
What is potato’s blight and what does it do
Fungus
The hyphae penetrate host cells, destroying leaves, tubes and fruit and causing millions pounds worth of damage each year
Method of transmission is Spores being carried by wind from plant to plant
What is black Sigatoka
Banana disease caused by fungus
Hyphae penetrate and digest the cellls turning leaves black
Cause reduction ins yield
Method of transmission is leaf to leaf contact or preadolescent of spores by humans or within infected plant matter
What is TB
Bacterial disease
Damages and destroys lung tissue and suppresses the immune system
Makes body less able to fight of other diseases
Treatment: antibiotics
Presentations: improving living standards vaccination
Bacterial meningitis
Bacterial infection
Meninges of the brain spread into the rest of the body causing septicaemia and rapid death
Symptoms: blotchy red/purple rash that doesn’t disappear when glass pressed on it
Prevention: vaccine
Treatment: antibiotics
What is HIV
Is a virus infection
Infects T helper cells in the immune system
HIV destroys the T helper cells of the immune system of affected people so more susceptible to other infections
Spread by exchange if bodily fluids
Treatment: antiretroviral drugs slow process of disease
Prevention: no vaccine or cure, don’t reuse needles, safe sex
HIV replication
HIV I had RNA as its genetic material and contains the enzyme reverse transcriptase which transcribes RNA to a single strand DNA of host cell
Describe Influenza
Viral infection of the ciliated epithelium cells in gas exchange system
Kills cells making them airways open for secondary infection
Treatments: hydrate ibuprofen
Prevention: flu vaccine
Outline malaria
Protocista
Spread by bites of infected mosquitoes
Prevention: vaccine,nets repellent, long clothing
Treatment, anti malaria drugs
Plasmodium lifecycle
- Mosquito bites person transferring plasmodia into the blood
- Plasmodia reproduce sexually in mosquito
- Mosquito sucks blood containing plasmodia
- Plasmodia burst out of red blood cells
- Plasmosia reproduce asexually in liver cells and the burst out of liver cells and plasmodia entered the liver
- It enters the red blood cells and reproduce asexually again
Ring worm
Fungal disease
Circular areas of skin which is itchy
Prevention - keep areas dry and clean
Treatment - antifungal cream
When plants are attacked by pathogens they set up mechanical defences what are they
They produce Callose
scientists do not fully understand role of callose but resesrch suggests
- Within minutes of initial attack callose is synthesised and deposited between cell wall and cell membrane in cells next to infected cells
- callose acts as a barrier
- Lignin is added making mechanical barrier thicker and stronger
- Callose blocks sieve plates in phloem sealing of infected parts
- callose is deposited in the plasmodesmata between infected cells as their neighbouring cell
Sends alarm signals to uninflected cells so they can put defences in place
Atheletes foot
Fungal disease
Grows on and I
Digest the warm moist skin on feet
Can be itchy and sore
Treatment: antifungal cream
Prevention: dry areas
What are the two main types of of transmission
Direct and indirect
Name direct transmissions and examples
Direct contact - kissing,skin to skin, from faeces
Inoculation - brakes in the skin eg during sex, animal bite, puncture wound or needles
Ingestion - contaminated food or drink
Name indirect transmission
Forties- inanimate object eg bedding socks
Droplet infection (inhalation) - droplets fromsaliva mucus cough or talk
Vector- vector transmit communicable disease
What are factors affecting the transmission of communicable disease in animals (7)
Overcrowded living and working conditions
Poor nutrition
Compromised immune system
Climate change - Increase in temp results in sweating and wind and vectors love more in hotter temp
Culture- physical contact different to each an
Infrastructure waste management
Socioeconomic factors lack of trained health workers
Direct transmission of plants
Direct contact of healthy plant touching any part of a diseases plant
Indirect transmission of plants
Soil contamination
Vectors - wind, water, animals, humans
What factors affect the transmission of communicable diseases in plants
Planting varieties of crops thst are susceptible to disease
Over crowding
Poor mineral nutrition
Deep warm conditions
Climate changes
How do plant recognise an attack
Receptors in cells respond to molecules from pathogens or to chemicals produced when attacked
Stimulates release of signalling molecules — which switch on genes
This triggers cellular responses
When plants are attacked by pathogens they set up a mechanical defence what are they
The produce Callose scientists do not fully understand role of callose but resesrch suggests
- Within minutes of initial attack callose is synthesised and deposited between cell wall and cell membrane in cells next to infected cells
- callose acts as a barrier
- Lignin is added making mechanical barrier thicker and stronger
- Callose block sieve plates in
Phloem is desposited in the plamodesmata between the infected cell and neighbouring sealing them of healthy cells
What does callose do to the pant
It prevents pathogens enetering plant cell
It can Also seal off the infected part preventing spread of pathogen
What is non specific
Means it’s present at birth, defends don’t distinguish between different pathogen they give same responses each time a particular pathogen enters body
Act quickly but aren’t always effective
What are one primary response that event pathogen entering body
- Skin
- Mucous membrane
- Blood clotting
- Inflammation
- Wound repair
- Expulsions reflex’s
- Tears
- Saliva
How does the skin prevent pathogen entering
The epidermis made by cells called keratinocytes the cells are produced by mitosis at base of epidermis and Migrate to the surface of the skin then when cells then when cells get to surface they are dead and act as effective barriers
Blood clotting
Temporary seal made of protein fibrin
it involves calcium ions and 12 clotting factors.
Clotting factors released from platelets and damaged tissues thromboplastin is an enzyme that triggers cascade resulting in large amount of fibrin to seal wound serotonin contracts smooth muscle to slow blood flow
Wha a the enzyme invoked in blood clotting
Thromboplastin
Inflammatory response
Mast cells activated in damaged tissues and release chemicals called histamines and cytokines
- histamines make blood vessels dilate causing localised heat and redness this raises temperature which prevents pathogens reproducing
- makes blood vessels walls leaky forcing blood plasma out which is then known as tissue fluid which causes swelling and pain
Cytokines attract white blood cell to site they dispose pathogens by phagocytosis
Accumulation of dead phagocytes and pathogen forms visible pus layer
What are the two monotype of phagocytes
Neutrophils
Macrophages
What is the star of phagocytosis
- Pathogens produce Chemical that attract phagocytes
- Phagocyte bind to oponsin attached to antigen of pathogen
- Phagocyte engulfs the pathogen o form phagosome
- Lyosome moves towards and fuses with phagosome o form phagolyosome releasing lytic enzymes that break down pathogen
- After digestion harmless products are absorbed and antigens Connie with MHC in cytoplasm
- MHC complex is displayed on phagocyte membrane making an antigen presenting cell APC
What is meant by the term communicable disease
Disease that can be passed from one organism to another organism
Explain the difference between the way virus and protist cause disease
Viruses insert genetic material into host DNA and take over cell metabolism to make new viruses before breaking out of the cell protists take over cells and feed on cell contents and divide before breaking out of cell
What are some chemical defenders of plants
Insect repellants
Insecticides
Antifungal compounds
General toxins
Antibacterial. Compounds including antibiotics
How does cytokines make the process of phagocytosis more effective
Cytokines act as cell signalling molecules which informs phagocytes that the body is under attack and stimulating them to move to site of infection they also increase body temperature and stimulate specific immune system
When viewing a blood smear what could u see
Red blood cell- no nuclei and distinct biconcave shape
White blood cell - irregular shapes
Neutrophils - distinct lobed nuclei
Lymphocytes - large nuclei nearly occupy the entire cell
How does opsonins make the process of phagocytosis more effective
They. Are chemicals that bind to pathogens and tag them so they can be easily recognised by phagocytes phagocytes have receptors on their cell membrane that bind to common opsonins
What does antigens trigger
Antigens trigger an immune response which involves the production of polypeptides called antibodies
Strucutre of antibodies
Y shaped glycoproteins called immunoglobulins
What do antibodies do
Immunoglobulins bind to specific antigen on the pathogen or toxin that has triggered the immune response
What are antibodies made up of
Antibodies are made up of two identical long polypeptides chains called the heavy chains ans two shorter identical chains called the light chains
Chains held together by disulfide bridges
What is formed when an antibody binds to an antigen
It forms an antigens - antibody complex
How do antibody gets its specificity
Antibodies bind to antigens with a protein based lock and key mechanisms
Binding site is an area of 110 amino acids on both the heavy and light chains
It is different shape on each antibody
This gives the antibody is specificity
What does the hinge region of the antibody provide the molecule
Provides molecule with flexibility allowing it to bind two separate antigens one at each of its antigen binding sites
How do antibodies defend the body
- The antibody of the antigen and antibody complex acts as an opsonin so complex is easily engulfed and digested by phagocytes
- Pathogens can no longer invade host cells once part of an antigen antibody complex
- Antibodies act as agglutinates
- Antibodies can act as anti toxins
Antibodies act as agglutinins what does this do
Causes pathogens carrying antigen-antibody complexes to clump together. This helps prevent them spreading through the body nd makes it easier for phagocytes to engulf lots Of pathogens at the same time
The specific immune system is based on white blood cells called
Lymphocytes
B lymphocytes mature in the bone marrow
T lymphocytes mature in the thymus gland
What are the three main types of t lymphocytes
T helper cells
T killer cells
T memory cells
T regulator cells
T helper cells
- have CD4 receptors on cell surface membrane which binds to surface antigens on APCs
- produce interleukins this stimulates the activity of b cells which increase antibody production, stimulate production of other types of T cells and attracts and stimulates macrophages to inject pathogens with antigen-antibody complexes
T killer cells
Destroy pathogen carrying antigen
Produce chemical callled perforin which kills pathogen making holes in cell surface membrane
T memory cells
These live for a long time and part of immunological memory
If antigen is met for a second time they divide rapidly to form a huge number of clones of t killer cells that destroy the pathogen
T regulator cells
These cells suppress the immune system
Acting to control and regulate it
It makes sure the body recognises self antigens and does not set up an autoimmune response
Interleukins are important in this control
What are the main types of b lymphocytes
Plasma cells
B effector cells
B memory cells
Plasma cells
Produce antibodies to particular antigen and release them into circulation
Active plasma cell as only live for a few days but produce 2000 antibodies per second while alive and active
B effector cells
Divide to form the plasma cell clones
B memory cells
Live for a long time and provide immunological memory
Programmed to remember a specific antigen and enable th body to make a rapid response when pathogen carrying antigen is encountered again
What happens in cell mediated immunity
T lymphocytes respond to cells of an organism that have been changed in some way by antigen processing or by mutation and to cells from transplanted tissue
What is an autoimmune disease
When immune system stops recognising self cells and starts to attack healthy body tissue
What is a pandemic
Is where the same disease spreads rapidly across a number of countries and continents
What is herd immunity
Using a vaccination to provide immunity to all/ almost all of the population at risk 80-85%
What is ring vaccination
Vaccinating all people in immediate vicinity of the case
What is acitve natural immunity
The immune system produces T and B memory cells so if u meet the pathogen again your immune system recognises the antigens and can immediately destroy pathogen before it causes disease
What is natural passive immunity
Where a mother passes on antibodies to babies
- some antibodies cross the placenta from mother to her fetes
- breast feeding first milk is called colostrum which is high in antibodies
What is artificial passive immunity
Antibodies formed in one individual extracted and then injected into bloodstream of another individual giving temporary immunity
What is artificial active immunity
Immune system of body is stimulated to make its own antibodies to a safe form of an antigen which is injected into bloodstream
Vaccines can contain what antigen material
Live and whole pathogen
Dead pathogen
Attenuated pathogen
Toxoid
Surface antigen
What is a vaccine
A biological preparation that provides active acquired immunity to a particular infectious disease
What steps are involved with the use of vaccine
- Pathogen made so antigens intact but no risk of infection
- Vaccine injected into bloodstream
- Primary immune response is triggered and body produces antibodies and memory cells
- If in contact with live pathogen the secondary immune response is triggered and destroy pathogen rapidly before symptoms of disease
What is a epidemic
When communicable disease spreads rapidly to a lot of people at a local or national level
What problems can occur durimg vaccination
- Poor immune system
- Antigenic variance
- Antigenic concealment - hide in cells
- Overly scared of side effects
- Economic boundaries
What is antigenic variance
Antigenic drift - slight changes so memory cell stilll recognised
Antigenic shift - major and changes not recognised
Antibody function - neutralising toxins
Mayn’t pathogens can produce endotoxins which harm the host organism
Antibodies bind to endotoxins and neutralise them
Antibody function - neutralising antigens
Antibodies can directly neutralise viruses
Viruses have a attachment proteins that bind to and infect host cell
An antibody bind to these viral attachment proteins so virus cannot infect cells
Antibody function - agglutination
Antibodies will clump pathogen togehter
Antibodies can ind to multiple antigens so clump pathogen this big group cannot infect cells ans makes it easier for phagocyte to engulf multiple pathogen in one go
Antibodies function - marking
Antibodies mark pathogens they bound to a pathogen and are beacons for immunological cells and attract phagocyte and lymphocytes to the area
What are consequences of antibiotic resistance
Antibiotics become less effective as
- overuse of antibiotics and them being prescribed when unnecessary
- patients failing to complete full course of antibiotics
- large scale use of antibiotics I farming to prevent disease when livestock are in close quarters even when animals not sick
How to reduce antibiotic resistance
- tighter controls in countries in which antibiotics are sold without doctors prescription
- doctors avoiding the overuse of antibiotics
- must finish entire course of antibiotics
- them not being used for viral infection
- ## type of antibiotics being changed so same antibiotic is not always prescribed
What are antibiotics
The are chemical Substances that inhibit or kill bacterial cells with little or no harm to human tissue
Antibiotics are either described as being
Bactericidal ( they kill)
Bacteriostatic ( inhibit growth processes)
