ch. 43 part 1 Flashcards
pathogen
any agent that causes disease and infects a wide range of animals (including humans)
ex. of pathogens
- parasites
- protozoa
- fungi
- prokaryotes
- viruses
- prions
2 types of molecular recognition for detection of non-self molecules, particles, and cells
- innate immunity
- adaptive immunity
where is innate immunity found
in all animals and plants
innate immunity in vertebrates
- first response to infection
- foundation adaptive immunity
ex. of innate immunity in insects
- exoskeleton made of chitin forms first barrier to pathogens
- digestive system protected by chitin-based barrier and lysozyme (breaks down bacterial cel walls)
- hemocytes circulate within hemolymph and carry out phagocytosis
- immune system recognizes bacteria/fungi by structures on cell walls
- defense against viruses based on recognition of double-stranded RNA
hemocyte function in insects
- secrete antimicrobial peptides that disrupt the plasma membranes of fungi/bacteria
- carry out phagocytosis in hemolymph
what are the innate defenses of mammals similar to?
those of invertebrates
innate defenses of mammals/invertebrates
barrier defenses, phagocytosis, antimicrobial peptides
innate defenses unique to vertebrates
- natural killer cells
- interferons
- inflammatory response
innate immunity definition
general recognition that something is foreign
barrier defense examples
- skin and mucous membranes of respiratory, urinary, reproductive tracts
- lysozymes that break cell walls in tears, saliva, and mucous of eyes/upper respiratory tract
what does mucus do
trap and allow for removal of microbes
what body fluids are hostile to microbes?
saliva, mucus, tears
what do the low pH of skin and digestive system do
prevent growth of many bacteria
cellular innate defenses (mammals)
- detect, devour, destroy pathogens
how do mammal cells recognize groups of pathogens
TLRs
TLRs - toll-like receptors
recognize fragments of molecules characteristic of a set of pathogens
2 main types of phagocytic cells in mammals
- neutrophils
- macrophages
neutrophils
phagocytic cells that circulates in blood and destroy infected cells
macrophages
phagocytic cells that migrate through the body or reside permanently in organs/tissues
2 additional types of phagocytic cells
- dendritic cells
- eosinophils
dendritic cells
stimulate development of adaptive immunity
- populate tissues that come in contact with the environment
- migrate to lymph nodes after detecting pathogens
eosinophils
discharge destructive enzymes against parasites - multicellular invaders
natural killer cells
tumors, cancers
- circulate through body and detect abnormal cells
- release chemicals leading to cell death, inhibiting spread of virally infected/cancerous cells
what system do many cellular innate defenses involve
lymphatic system
how do peptides and proteins function in innate defense
by attacking pathogens or impeding their reproduction
interferon proteins
innate defense by interfering with viruses and helping activate macrophages
- limit cell-cell spread of viruses
- infected cells release interferons which signal other cells
complement system
causes lysis of invading cells and helps trigger inflammation
how many proteins make up complement system
30
complement protein process
- circulate in an inactive state
- activated by coming in contact with a pathogen
- activation leads to pathogenic cell exploding
inflammatory response
pain and swelling brought about by molecules released upon injury or infection
mast cells
immune cells found in connective tissue
what do mast cells release
histamine
histamine function
triggers blood vessels to dilate and become more permeable
activated complement proteins
- promote further release of histamine
- attract more phagocytic cells
what does enhanced blood flow to a site do
helps deliver antimicrobial peptides
pus
fluid rich in white blood cells, dead pathogens, and cell debris from damaged tissues
what type of inflammation is a fever
systemic - triggered by substances released by macrophages in response to certain pathogens
types of inflammation
local or systemic