Disease Flashcards
(44 cards)
Virus
-Not alive
-Cannot reproduce outside of cell.
-Capsid with sites to attach to host cells.
-Eg tobacco mosaic virus, HIV
Fungus
-Eukaryotic
-Chitin cell wall
-Can be single or multicellular
-Eg black sigatoka, ring worm
Bacteria
-Prokaryotic.
-Peptidoglycan cell wall.
-Divide by binary fission.
-Eg Ring rot, tuberculosis
Protists
-Eukaryotic.
-Singular or multicellular.
-Eg tomato blight, malaria.
Direct transmission
-Where a pathogen is passed from one organism to another without any stages.
Direct contact
-Two organisms touching.
-Skin to skin.
-Exchange of bodily fluids.
Inoculation
-Where the skin is broken and microorganisms enter directly.
Ingestion
-Where infected food or drink is consumed.
Indirect transmission
-When a pathogen is passed through an intermediate stage.
Fomites
-Inanimate objects with pathogens on.
Droplet infection
-Transfer of pathogens through sneezing or coughing.
Vectors
-Move to transfer pathogens to other places.
-Eg mosquitoes, wind, water
Factors increasing rate of transmission
-Overcrowding.
-Poor nutrition.
-Compromised immune system.
-Poor waste disposal and sanitation.
-Warm, damp conditions.
-Poor, crowded infrastructure.
-Increased rainfall or wind speed.
Bodily barriers to stop infection
-Skin is a physical barrier, and changes pH outside of bacterial optimum.
-Blood clotting forms a fibrin scab to prevent bacteria from entering the wound.
-Mucous traps pathogens.
-Coughs and sneezes expel pathogens.
-Inflammation increases blood flow by making capillaries more permeable, allowing more phagocytes onto tissues.
-Saliva contains lysosomes to destroy pathogens.
-Ear wax traps pathogens
-Stomach acid denatures enzymes in pathogens.
-Fever raises the body temperature, making enzymes in pathogens less effective.
Neutrophil
-Most common phagocyte.
-Multi lobed nucleus.
-Do phagocytosis.
Macrophage
-Largest phagocyte.
-Large nucleus.
-Become macrophages in tissue.
Monocytes
-Less common phagocyte.
-In tissues such as in the alveoli.
-Does phagocytosis.
Process of phagocytosis
-Phagocyte is attracted by chemical signals called cytokines to a tissue with a pathogen.
-Attracted by chemicals called opsonins produced by the phagocyte.
-Phagocyte identifies pathogen as non-self.
-Phagocyte’s cytoplasm engulfs the pathogen.
-Pathogen is contained within a vesicle called a phagosome inside the cytoplasm.
-Lysosomes move into the phagosome and fuse with it, delivering digestive enzymes.
-Phagocyte displays the pathogen’s antigens, becoming an antigen-presenting cell.
-This activates the specific immune response.
Secondary (specific) immune response
-Receptors on T-Lymphocytes bind to antigen of antigen-presenting-cell and are activated.
-Interleukins are produced by T-helper cells, which stimulate the production of more receptors complimentary to the antigen. This is known as clonal selection.
-T cells formed from clonal selection divide by mitosis.
T-Killer cells
-Formed from division of T-cells formed in clonal selection.
-Destroy complimentary pathogens by using perforins to punch holes in their membranes.
T-memory cells
-Formed from division of T-cells formed in clonal selection.
-Provides an immunological memory of specific pathogen.
-Can divide rapidly into many t-killer cells upon encountering the antigen a second time.
T-regulator cells
-Formed from division of T-cells formed in clonal selection.
-Suppress the immune system after the pathogen is destroyed.
-Prevent autoimmune response from T-killer cells.
T-helper cells
-Formed from division of T-cells formed in clonal selection.
-Can produce interleukins that either stimulate further phagocytosis or B-helper cells to divide.
B-Lymphocyte activation/humoral immunity
-B-lymphocytes are activated through encountering its complementary antigen (clonal selection) or by T-helper cells.
-They divide by mitosis (clonal expansion)
