Communicable Diseases Flashcards
How do parasites make people sick
Parasites live in host feed from host at the expense of the host
How is tuberculosis spread
Via inhalation of droplets released by coughing and sneezing
How do mosquitoes spread malaria
It is a vector and contains plasmodium in its saliva it then feeds on the human causing a break in its skin and the virus enters the blood
Why does the law on needles prevent spread of hiv
As it reduces the chance of sharing needles as they are contaminated
What is health
Health is being free from diseases. It is the physical and mental and social well-being .
How do bacteria make food go bad
Bacteria reproduce and secrete enzymes which destroys the food eg the proteins beckoned amino acids which causes the appearance to change
What vector helps malaria reproduce
Female anopheles
Why is it hard to make drugs for malaria
As there are different strands of plasmodium due to mutations so they would need a different vaccine . The parasite also hides inside the cells and is only exposed for a short time
Indirect vs direct
Direct transmission requires physical contact between the infected organism and an uninfected organism, eg influenza Indirect transmission relies on some kind of living or non-living “third party” such as a household object or an insect eg malaria Direct transmission is more common in animals than in plants (as plants are stationary), indirect is more common in plants.
How do plants spread disease
Via direct contact and vectors
Agglutinins
clump together pathogens making it harder to enter cells so more can be consumed by phagocytes at once.
why do neutrophils have a lobed nucleus
so that they can change shape to fit in between cells
what does the variable region do?
allows specifity to different antigens to prevent entry to host cells.
cytokines
Have a specific shape which binds to receptors on B lymphocyte to activate clonal expansion by mitosis
Humoral response
B cell has antigen receptors which is specific to only one antigen.Clonal selection is where B lymphocytes are activated y cytokines from T helper cells.Clonal expansion is where the cell divides by mitosis. B cell differentiates to form plasma cells which secrete antibodies which are specific to the antigen.They also make memory cells which are long lived and remain in the body.
what do memory cells do when a virus enters
memory cells recognise the antigens and divide to make clones they then differentiate into plasma cells which can make antibodies to fight the virus.
what does the constant region do
allows recognition by phagocytes and is where they bind to the phagocyte.
Describe the process by which a pathogen is destroyed after it has become attached to
the surface of a phagocyte
Pathogen is engulfed by endocytosis.phagosome forms and then fuses with lysosome to form a phagolysosome.Lysins digest pathogen into sugars and amino acids and then the unwanted products ate secreted by exocytosis.
opsonins
bind to antigen on pathogen and assist binding to phagocyte
differences between cell mediated and humoral immunity
Humoral immunity involves b lymphocytes which mature in the bone marrow whereas cell mediated involves t lymphocytes which mature in the thymus.In humoral immunity b lymphocytes can bind to pathogens and apcs whereas in cell mediated it can only bind to apcs.Humoral immunity differentiate into plasma cells and produce antibodies whereas cell mediated produce t killer cells which secrete perforin and pierce cell membrane.
similarities between cell mediated and humoral immunity
they both produce memory cells which circulate the body they both undergo clonal expansion and clonal selection.
neutralisation
when the active site is blocked as it binds to the pathogen so it cant enter the cell
how do phagocytes enter tissue
they pass from the blood to the tissue as they are lobed and so can change shape and histamine makes the walls more leaky.
histamine leaky
when leaky more tissue fluid is formed increases pressure in tissue causes swellling wbc pass into tissues larger molecules pass into tissue fluid
antigens
used for binding to host cell