Communicable Diseases Flashcards
pathogen
a microorganism that causes disease
direct transmission
passing a pathogen from host to new host with no intermediary
transmission
passing a pathogen from an infected individual to an uninfected individual
indirect transmission
passing a pathogen from host to new host via a vector
vector
an organism that carries a pathogen from one host to another
callose
a large polysaccharide deposit that blocks old phloem sieve tubes
inflammation
swelling and redness of tissue caused by infection
mucous membrane
specialised epithelial tissue that is covered by mucus
primary defences
those that prevent pathogens entering the body
antigen-presenting cells
a cell that isolates the antigen from a pathogen and places it on the plasma membrane so it can be recognised by other cells in the immune system
clonal selection
selection of a specific B or T cell that is specific to the antigen
cytokines
hormone-like molecules used in cell signalling to stimulate the immune response
neutrophil
a type of white blood cell that engulfs foreign matter and traps it in a phagosome which fuses with lysosomes to digest it
opsonins
proteins that bind to the antigen on a pathogen and then allow phagocytes to bind
antibodies
specific proteins released by plasma cells that can attach to pathogenic antigens
B memory cells
remain in the blood for a long time providing long-term immunity
clonal expansion
an increase in the number of cells by mitotic cell division
interleukins
signalling molecules that are used to communicate between different white blood cells
plasma cells
derived from B lymphocytes, they manufacture antibodies
T helper cells
release signalling molecules to stimulate the immune response
T killer cells
attack and destroy our own body cells that are infected by a pathogen
T memory cells
remain in the blood for a long time providing long-term immunity
T regulator cells
involved with inhibiting or ending the immune response
agglutinins
antibodies that cause pathogens to stick together
anti-toxins
antibodies that render toxins harmless
opsonins
antibodies that make it easier for phagocytes to engulf the pathogen
primary immune response
the initial response caused by a first infection
secondary immune response
a more rapid and vigorous response caused by a second or subsequent infection by the same pathogen
active immunity
where the immune system is activated and manufactures its own antibodies
artificial immunity
immunity achieved as a result of medical intervention
epidemic
a rapid spread of disease through a high proportion of the population
natural immunity
achieved through normal life processes
passive immunity
achieved naturally by another then antibodies are passed to the individual through breast feeding or injection
vaccination
a way of stimulating an immune response so immunity is achieved
antibiotic
a chemical which prevents the growth of microorganisms (antibacterial or antifungal)
personalised medicine
development of designer medicines for individuals
synthetic biology
the re-engineering of biology- production of new molecules that mimic natural processes or use of natural molecules to produce new biological systems that do not exist in nature
a host
an organism in which pathogens live, creates a good habitat but takes nutrition & damages in the process
why do bacteria and fungi often live in vascular tissue of plants
have access to the plants nutrients and water to replicate around the plant
social factors that affect direct transmission
overcrowding, poor ventilation/diet/health, homelessness, living/working with migrants from where disease is common
protoctists, bacteria and fungi grow and reproduce more rapidly in…
warm and moist conditions, warmer climates (damaged/even killed by cool climates)
passive defences in plants
defences present before infection, prevent entry and spread of pathogen
active defences in plants
when pathogens attack specific chemicals in their cell walls, it can be detected by plant cells that fortify the defences
why are most pathogens killed by the stomach
very acidic (pH1-2) which denatures its enzymes
why immunity takes time to develop
body has to encounter the pathogen
lymphocytes must divide to form clones
B lymphocyte have to secrete enough antibodies
T cells have to be produced and destroy all infected cells
…..in which this is enough time for the pathogen to replicate and cause illness
interferon
released by many cells to inhibit virus replication and stimulate T killer cells
herd vaccination
using a vaccine to provide immunity to almost all population at risk- once enough immune, disease can no longer spread
ring vaccination
used when a new case of disease is reported by vaccinating all people in immediate vicinity of it
process of an epidemic
when pathogens undergo genetic mutations which changes their antigens so memory cell produced by vaccination won’t recognise them –> pathogen transmitted –> some unstable so regularly undergo changes –> epidemic rise
what happens if you leave the disease area
no further exposure to pathogens so memory cells will die –> no immunological memory
transmission of malaria
bite from an infected femal Anopheles mosquito which carries the Plasmodium vivax parasite
