What are the 4 general types of pathogens
viruses, fungus, parasite, bacterium
What are the basic characteristics of immune responses
- most invertebrates can clear an infection, but can be infected again (no immune memory)
- not all responses are successful - some can lead to death or disease
- can result in the clearing of infecting pathogens
- successful immunity leads to immune memory
What is immune memory
when the immune system has already dealed with a disease and therefore is more prepared for further infection and has faster elimination then first time
What is variolation?
used in China which was used to immunize people against smallpox, where a dried version of smallpox was blown into the nasal passage
What were Edward Jenner’s observations
- noticed that english milkmaids got cowpox but not smallpox and it was less deadly with a lower portion of mortality
- Jenner used cow pox variolation to prevent smallpox infections
What are the three types of vaccines
- Attenuated: living but weak virus
- Inactivated: killed whole pathogen
- Subunit: parts or components of pathogen
What is immune priming?
large amounts of vaccine which leads to immune memory that protects when the vaccinated encounter the infecting pathogen
What are some risks with vaccinations
Can cause allergic responses (anaphylaxis), which can also be caused by vaccine quality or handling errors
What is Reproduction ratio?
of new infections caused by each infected person also known as transmissibility
How can we differentiate if a infection is a epidemic or not?
- if reproduction ratio is less than 1 - not an epidemic as infection will slowly die out
- if reproduction ratio is greater than 1 - then epidemic infection will spread in the population
What is herd immunity
proportion of a population that needs to be immune to prevent pathogen spread, based upon the reproduction ratio
What are some examples of viral entry routes
- respiratory
- oral - fecal transmission
- sexually
- needles
- through blood
What are some physical and chemical barriers of our body?
- mucous and mucous membranes
- acid in sweat (pH 4.5 - 6)
- acid in stomach (pH 2)
- anti-bacterial proteins and zinc in semen
- competition from commensal bacteria in gut and genital tract
- coughing
- cilia in respiratory trap foreign material
Mucus characteristics?
- mucous membranes cover 400 m2, while skin only covers 2m2
- lines the GI, respiratory and genitourinary tracts
- thin, permeable barriers
- gas exchange, food absorption, reproduction
What are goblet cells
secrete mucus - trap microbes
What is the ciliary escalator
- ciliated epithelial cells in trachea and nasopharynx, cilia push bacterial cells back up
- bacteria trapped by mucous and coughed out or swallowed and killed by stomach acid
What is normal microbial flora
- biological barrier to infection
- present on all body surfaces exposed to the environment
- area of higher moistures have higher normal flora
How does normal flora prevent infection
Microbial antagonism: as they already inhabitat our bodies, through habitat and competition for resources, this limits vacancy for pathogens
What are chemical barriers
enzymes that degrade microbial cell walls in saliva and anti-microbial peptides (AMPs)
- can punch holes in microbe membranes
What are AMPs also known as?
defensins
What is the function of the spleen in the lymphatic system
screens the blood
What is the function of lymph nodes
screens the bodies tissues
