Lecture 8- Innate Immunity Flashcards
what does the immune system do?
fights off foreign material that threatens the body and protects against disease
what are the two different types of immunity?
innate
adaptive
what is adaptive immunity?
highly specific
what is innate immunity?
non- specific
what does the innate immune system specifically do?
protects humans from most infectious diseases
when does immunity start?
at birth and is always present
what is natural host resistance?
host resistance has no memory but our susceptibility to pathogens varies from one species to another
what is an example of how susceptibility to pathogens varies from one species to another?
HIV can infect human cells but not mice
anthrax causes fatal blood infection in cattle but just a minor skin infection in humans
can the immune system be specific?
YES can be specific for a particular tissue
can pathogens be specific?
yes! they prefer a specific body site to initiate infection (some have specific receptors and bind to specific cell types)
how can pathogens spread?
aerosols (sneezing)
bodily fluids (blood)
what is Clostridium tetani?
anaerobic and thus prefer to live in our anaerobic bodies, can be ingested or can enter into deep wounds. this is why we get tetanus shot to prevent microbes like this
how does the innate immune system protect us? what barriers/ defenses does it have? (5)
physical barriers
chemical defenses
cellular defenses
molecular defenses
physiological processes
what are two main barriers to infection?
skin
mucous membranes
how does the skin act as a physical barrier?
prevents invasion by microbes because its slightly acidic (pH 5) which microbes dont like
high NaCl (because salty microbes dont like this)
what is the skin made of?
keratin which is a tough protective protein
what can grow on the skin and how?
fungal infections can grow on skin surface can break skin to get in but many require broken skin in order to penetrate and cause infection
what is mucous produced by?
goblet cells which trap microbes preventing infection
what does a mucous membrane do?
line tracts in the body and contain antimicrobial secretions
what tracts does the mucous membrane line? 4
respiratory tract
gastrointestinal tract
large intestine (colon)
genitourinary tract
what does the respiratory tract contain?
mucociliary escalator
what do the mucosal epithelial cells within the respiratory tract contain?
cilia
what do cilia do in the respiratory tract?
filter incoming air through a sweeping action
the sweeping action allows for removal of mucous and trapped microbes from the lungs
what are the two major components of the gastrointestinal tract?
stomach
small intestine
do many microbes survive in the stomach? why?
no because its a very acidic environment (pH 2) and contains proteases
how does the small intestinal tract counteract the high pH of the stomach?
pancreatic juice that contains pancreatic enzymes buffers acidity of incoming contents from the stomach (pH 7)
do many microbes live in the small intestine?
no, the microbes cant maintain cellular integrity in the harsh environment with the bile
what does the large intestine contain?
normal microbiota
where does a normal microbial resident that lives in the large intestine live symbiotically?
inside the colon
how do microbes living in the large intestine and colon persist?
by using attachment sites
what does it mean to consume undigested nutrients in the large intestine?
competitive exclusion
what does it mean to produce antimicrobial compounds in the large intestine?
microbial antagonism
