Communicable Diseases Key Terms and Processes Flashcards
Define the term :
Health
State of mental, physical and social well being, not just the absence of disease
Disease: Tuberculosis
Type of pathogen and name?
Method of transmission?
Treatment?
- Bacterium, Mycobacterium Tuberculosis or M.bovis
- Indirect transmission; inhalation of infected droplets in the air
- Antibiotics taken for 4-6 months
Disease: Meningitis
Type of pathogen and name?
Method of transmission?
Treatment?
- Bacterium, Neisseria meningitidis, Haemophilus influenzae
- Direct transmission with exchange of body fluids eg: kissing; also indirect transmission by inhalation of airborne droplets
- Antibiotics, vaccines for some forms
Disease: HIV/AIDS
Type of pathogen and name?
Method of transmission?
Treatment?
- Virus, Human immunodeficiency virus
- Direct transmission, through unprotected sex, unscreened blood, during birth, breast milk
- No cure or vaccine, antiviral drugs to reduce viral load in the blood, treatments for opportunistic infections
Disease: Influenza
Type of pathogen and name?
Method of transmission?
Treatment?
- Virus, Influenza A, B, C or D
- Indirect transmission through inhaling airborne droplets, very small % through eating or drinking contaminated, unpasteurised dairy products from infected cattle
Disease: Malaria
Type of pathogen and name?
Method of transmission?
Treatment?
- Protoctista, Plasmodium falciparum, P. ovale, P. malariae, P. vivax
- Indirect transmission through female = anopheles mosquito (vector)
- Drugs available, resistance is increasing, preventative measures more effective
Disease: Ringworm
Type of pathogen and name?
Method of transmission?
Treatment?
- Fungus, Trichophyton verrucosum
- Direct transmission, skin to skin contact
- Antifungal cream
Disease: Athlete’s Foot
Type of pathogen and name?
Method of transmission?
Treatment?
- Fungus, Tinea Pedia
- Indirect contact such as contact with towels used by infected people, and direct transmission with skin to skin contact
Function of the :
Red Blood Cell
- transports oxygen and carbon dioxide
Function of the :
Neutrophil
- undertakes phagocytosis
- short lived cell
- produced in bone marrow
- circulates in blood
- lobed nucleus, granular cytoplasm with many mitochondria, ribosomes and lysosomes
Function of the :
T-Killer
- white blood cell part of the specific immune response
- produced in bone marrow, matures in thymus gland
- kills infected body cells and pathogens using lysins and perforin
Function of the :
B-Lymphocyte
- white blood cell is part of the specific immune response
- produced and matures in bone marrow
- produces antibodies via a plasma cell
Function of the :
T-Helper
- white blood cell part of the specific immune response
- produced in bone marrow, matures in thymus
- coordinates B and T killer lymphocytes and macrophages through cell signalling molecules such as interleukins
Function of the : ]
B-Memory
- long lasting white blood cell produced during clonal expansion
- important in secondary immune response
Function of the :
Regulatory T-Cells
- type of t-cell that regulates and supresses the ummune system to prevent autoimmune responses
- prevents over response when pathogens have been destroyed
Function of the :
T-Memory Cells
- long lasting white blood cell produced during clonal expansion
- important in faster secondary immune response
Describe the non-specific immune response of blood clotting
- when a blood vessel becomes damaged, platelets become sticky and clump forming a temporary plug which activated thromboplastin
- thromboplastic activates prothrombin in the plasma which is converted into thrombin
- thrombin activates fibronogen (soluble) and is then converted to fibrin (soluble)
- this forms a fibre mesh and taps more platelets and RBCs forming a bloodclot
- clot will be digested by enzymes when wound is healed w/ new cells formed by mitosis
- vasoconstriction in arteries and arterioles in damaged areas mediated by serotonin released by clumping of platelets in contact with collagen in skin which decreases blood flow to the damaged area, reducing blood loss
Describe phagocytosis
- phagocyte stimulated by presence of foreign antigens or anitbodies bound to pathogens, or opsonins
- CSM is extended around the pathogen
- pathogen engulfed as endocytosis vesicle
- lysosomes containing enzymes and lysins moves towards engulfed pathogen using the cytoskeleton and ATP
- lysosome fuses with phagosome (both have phosphoplipid bilayer) to form a phagolysosome
- digestive enzymes hydrolyse and breakdown pathogen, products of digestion could include amino acids, fatty acids and glycerol, and glucose
Cytokines cause :
- other phagocytes to enter infected area
- stimulation of specific immune response
- rise in body temperature
Opsonins coat..
… pathogens with antibodies
What is an antibody?
a soluble protein that fits around an antigen and is involved in the destruction of a pathogen
Function of the :
Variable region
in an antibody
specific sequence of amino acids (110) whose 3D shape is complimentary to a specific antigen where it will bind
Function of the :
Hinge region
in an antibody
allows flexibility of aintibody when it binds to more than one antigen
Function of the :
Disulphide bridge
in an antibody
keeps the light and heavy chains joined together
Function of the :
Constant region
in an antibody
allows attachment of antibody to phagocyte to allow phagocytosis of the pathogen
Function of the :
Plasma cell
produces antibody by protein synthesis
Natural Passive Immunity
- from mother to baby, in utero transfer of antibodies through the placenta, after birth through breast milk, antibodies are transferred
- short term provision of antibodies, temporary protection, plasma cells don’t produce antibodies
Natural Active Immunity
- response to an infection
- long term immunity
- B and T memory lymphocytes produces as a result of infection and encountering an antigen
Artificial Passive Immunity
- antibodies are injected into an individual to provide instant immunity
- short term provision of antibodies, temp. protection
- B and T cells not activated, plasma cells don’t produce antibody
Artificial Active Immunity
- vaccinations
- long term immunity
- B and T memory lymphocytes produced as a result of vaccine and encountering an antigen
Vaccinations
- provide long term immunity to many diseases and help prevent epidemics, or pandemics
- contain specific antigens that when injected into the body stimulate the immune system to produce antibodies by plasma cells and memory cells
The antigen can be in 5 different forms:
- pathogen could be inactive or dead
- pathogen can be weakened (attenuation)
- toxins that the pathogen produces may be detoxified so they don’t cause disease
- antigens may be isolated from the pathogens
- the antigen may have been genetically engineered
Herd Immunity
occurs when vaccination pf a significant portion of a population provides a measure of protection for susceptibles
Ring Vaccination
Controls an outbreak by vaccinating and monitoring a ring of people around the infected individual , when an infection is diagnosed, all people who have been exposed are vaccinated
Antigenic Drift
DNA mutations in DNA which make small changed=s in the amino acid sequence, this means that the antigens on the CSM change
Antigenic Shift
The whole pathogen changes
Specific Immune Response by B Lymphocytes
Humoral Response
- form and mature in the bone marrow, circulate in the liver and spleen
- when pathogen has evaded first and second line of defense, B Lymphocyte will encounter the pathogen either on an infected body cell, an antigen presenting cell or the pathogen directly
- antigen and B Lymphocyte bind (clonal selection)
- B Lymphocyte will then divide by mitosis, the cells will then differentiate into either plasma cells that produce antibodies by protein synthesis, or B Memory cells; this is the primary immune response
- the antibodies are specific to one specific antigen and act in two main ways; agglutination or neutralisation
- B memory cells can last for years, if the same type of pathogen is encountered again, these memory cells will undergo a faster response at a higher jesus. and will last for longer
The specific immune response by T-Killer and T-Helper cells
Cell Mediated Immunity
- formed in bone marrow, mature in thymus, circulate in the blood and lymphatic system
- receptors present on CSM
T-Helper Action - when an individual has been infected with a pathogen that has evaded the fist and second line of defense, the specific T-Helper cell will encounter the pathogen either on an infected body cell, an antigen presenting cell or the pathogen itself
- antigen and and T-Helper cell bind: clonal selection
- T-Helper lymphocyte divides by mitosis: clonal expansion
- T-Helper cells release cytokines into blood plasma, which stimulates the B-Lymphocyte to undergo faster clonal expansion and differentiation into plasma cells that produce antibodies
- the cytokines also stimulate macrophages to undergo phagocytosis
- T-Helper memory cells also produced by clonal expansion which are then used in the secondary immune response
T-Killer Action - when the pathogen’s antigen and T-Killer bind: clonal selection
- the T-Killer Lymphocyte then will divide by mitosis: clonal expansion
- 2 types of T-Killer cells arise from differentiation; T-Killers that secrete enzymes and toxins and T-Memory cells which are used in the secondary immune response
Function of antibiotics
- used to treat bacterial infections
- targets different metabolic processes within the bacterium to ultimately cause it’s death, preventing further transmission and infection, but do not affect host cell metabolism, this is selective toxicity
Describe Antibiotic Resistance
- there is a bacterial infection
- antibiotics are taken, this acts as a selection pressure
- most bacteria will die, but some may remain as they have a beneficial allele (that has arisen randomly, as DNA mutations are random) which makes them resistant to the antibiotics taken, survival of the fittest
- these bacteria remain in the body and reproduce asexually via binary fission, so the offspring will have this beneficial, resistant allele
- these mutated bacteria survive the next dose of antibiotics, and the beneficial allele becomes more common in the population of bacteria
Describe Conjugation
When bacteria donates it’s DNA through a conjugation tube to another bacteria
What is an autoimmune disease?
The immune system begins to attack self cells
eg: Lupus, Hashimoto’s Disease, Rheumatoid Arthritis
can be caused by environmental factors, pollutants, stress or genes
