Unit 6 - Infection and Defects in Defense Flashcards
Descriptions of pathogens
Virulence- Reaction
Pathogenicity - How likely to produce disease
Communicability - Spread
Infectivity - Invasion
Bacteria
Prokaryotes
Aerobic or Anaerobic
Mobile or Immobile
Gram + vs Gram - Bacteria
Gram (-) has an additional membrane component that is a carbohydrate layer. Gram (+) easier to fight.
Virus
Nucleic Acid protected by protein layer capsule.
Virion attaches to cell,
Can now affect or penetrate.
Gets out of its shell, enters nucleus and replicates.
Replications mature, exocytosis to leave cell and go get more cells infected.
Cytopathic effects of virus
Stops DNA production.
Keeps immune system busy.
Turns host into cancer cells.
Disrupts lysosomal membranes.
Bacteriostatic vs Bacteriocidal
Static - Stops growing.
Cidal - Kills bacteria.
Immune Deficiency
Failure of immune system to function properly, resulting in increased susceptibility to infections. Congenital or acquired.
Retroviruses
Reverse Transciptase - converts RNA to DNA. Insert their own DNA into genetic DNA
Two enzymes in retroviruses
Reverse transcriptase and integrase.
How retrovirus “HIV” works
Virion attaches to CD4 and chemokines on T helper cells.
Fusion of HIV membrane. Genetic material leaks in (HIV RNA)
Reverse transcriptase converts the RNA to DNA.
HIV DNA goes into the nucleus, integrates into host DNA with integrase.
Makes HIV transcript (synthesis by proteases) which spreads to other host cell.
Hypersensitivities
“Allergies”. IgE antibodies and mast cells.
Re-exposed to allergens.
Allergen bound to antibodies presented to mast cells. Mast cells deregulate and produce histamine. Histamine causes itching, smooth muscle contraction.
Types of immune Defects
Hypersensitivities, Primary (Congenital), Secondary (Acquired)
