immune Flashcards
immune system organization
- innate-nonspecific
- adaptive-specific, based on experience
innate immunity
all animals have it
- exists prior to immune change
- low specificity
- rapid
- no memory of recurring infection
- 2 lines of defense
pathogen
disease-causing bacteria, viruses, worms, fungi, protists
first line of defense
- epithelial–most important
- exclude pathogens
- inhibit microbe growth
- damage microbes
- wash away–saliva, tears, mucus
- inhibit microbe growth–ph down
second line of defense
- cellular
- leukocytes–give generic response that is directed against any pathogen
- white blood cells
- in circulation and lymph nodes
inflammatory response
- platelets release proteins that form clots
- wounded tissues and macrophages secrete chemokines
- mast cells release histamines to constrict blood vessels and reduce blood flow
- neutrophils migrate to site of infection
mast cells
secrete histamines, lower blood flow from wound and increase to wound
neutrophils
- kill invading cells by phagocytosis
- many, short lived
macrophages
- release cytokines that recruit other cells to wound site
- kill invading cells by phagocytosis
antigens
foreign molecules that activate immune response
cytokines
- produced by injured tissues and macrophages
- mark path to wound
- induce fever
- increase leukocyte production
pattern recognition receptors
- recognize specific pathogens
- specific antogens made by all pathogens withing a group
- do not recognize host-specific molecules
- transduce signals resulting in cellular responses
- toll-like receptors are subset of
antimicrobial proteins
- nonspecific, numerous
complement system
a protein tag signals microbe location and antimicrobial activity
interferons
proteins released in response to viral infection, signals to neighboring cells
adaptive immunity–third line of defense
- lymphocytes
- vertebrates only
lymphocytes
- produced in bone marrow
- B cells mature in bone marrow
- T cells mature in thymus
- lymphocites activated in spleen and lymph nodes
lymphocite attributes
- specificity respond to specific microbe/pathogen strains
- diversity–recognizes a limitless array of antigens
- memory–reactivated quickly if recognizes antigens from previous infection
-
self-nonself recognition–molucles that are produced by individual do not act as antigens
- if cell has anti-self receptors, then destroyed
immunological memory
- shorter latency to response
- amplified response
t-cell mediated immunity
- intracellular pathogens
- rejection of transplanted tissue
- attack of cancerous cells
dendritic cells
- collect antogens, report to lymph nodes and present them to lymphocytes
- activate T cells via MHC antigen activation
key event that links innate and adaptive
antigen presentation–with out the transfer of information, adaptive immune response would not be activated to respond to infection
activated t cells
- directly kill cells–killer T
- secrete cytokines (induce fever and stimulate leukocyte division)–helper T
Helper T
fully activate B cells
what do b cells do
produce antibodies
what do T cells do
involved with graft rejection, recognizing and killing infected host cells
complement protein
punch hole in plasma membrane
lymphatic system
- digestion, circulatory, immune
- collect debris
- contain lymphocytes and macrophages
lysozyme
antibiotic that digests bacterial cell walls
