Introduction Flashcards
What are the general types of pathogens?
Virus
Fungus
Parasite
Bacterium
How do invertebrates and vertebrates differ in immune responses?
Invertebrates can clear infection but are soon susceptible again
Vertebrates gain immune memory when they clear an infection
How did the Chinese immunize people against smallpox?
They dried and powdered smallpox scabs and blew them into nasal passages - variolation
What did Edward Jenner do?
Used cow pox as a new form of variolation that has no mortality risk
What is an attenuated vaccine?
Living but weak virus
What is an inactivated vaccine type?
The pathogen is inactive (killed)
What is a subunit vaccine type?
Contains parts or components of a pathogen
What does immune priming in response to a vaccine lead to?
Immune memory that protects when the vaccinated encounter the infecting pathogen
What are the risks of vaccinations?
Anaphylaxis
Vaccine quality or handling errors
What is reproduction ratio?
The number of new infections caused by each infected person
>1 = epidemic
What is herd immunity?
The proportion of a population that needs to be immune to prevent pathogen spread
The more easily transmitted the pathogen, the higher the population proportion needs to be immunized to prevent spread
What are some examples of viral entry routes?
Conjunctiva
Arthropod
Respiratory tract
Scratches
Alimentary tract
Urinogenital tract
Anus
Skin
What are the behavioral barriers to becoming infected?
Staying home
Washing hands
What are the physical barriers to becoming infected?
The skin
Coughing and sneezing
Mucus and intact mucous membranes
Cilia in the lungs
What are the chemical barriers to becoming infected?
Enzymes in mucus, tears, and saliva
Acid in sweat and stomach
Competition from commensal bacteria in the gut and genital tract
Anti-bacterial proteins and zinc in semen
What is mucus?
Lines the GI, respiratory and genitourinary tracts
Thin, permeable barriers
Gas exchange, food absorption, reproduction
What are goblet cells?
Secrete mucus, traps microbes
What is the ciliary escalator?
Cilia push bacterial cells back up
Bacteria trapped by mucus and coughed out or swallowed and killed by stomach acid
What is microbial antagonism?
Normal flora inhibits colonization by pathogenic microorganisms through occupation of habitat and competition for resources
What are chemical barriers?
Enzymes that can degrade microbial cell walls in saliva and anti-microbial peptides (AMP)
What can AMP do to microbes?
Punch holes in microbe membranes
What happens to captured pathogens?
They are taken to the nearest lymph node or to the spleen where circulating lymphocytes transit to see if they recognize it
