immune system Flashcards
(12 cards)
bacterias form of immunity and amobea and nemotodes
CRISPR and sentinel cell - immune cells
antimcrobial peptides
- immunity is ancient
lymphatic system
- network of lymphatic vessels, lymph nodes, and lymphoid organs. It helps maintain fluid balance, filter waste, and defend against infections
-lymph vessels don’t have a pump ie. no heart , movement of body ie muscles squeeze and squish fluid around - lymph node - cervical lymph nodes msot commonly known (neck) as first point of contact, areas cells get together to coordinate activities/ centres of control
- a system of vessels that drain lymphs from tissues to lymph nodes in passive way to sense things are presence (pathogens)
thymus = under neck
spleen = middle of body
= both crucial for production of wbc, immune compromised if removed
major steps of immunity
-barriers = skin, mucous
-alarms = macrophages, tissue response
first responders = neutrophils
messangers = dendritic cells, macrophages
survelinnace and coordination = t cells
ogioing defense = b cells and antobody
barriers
epithelia cells - sealed by tight junctions
external epithelium is keratinised - protein in hair and nails, dead, difficult to penetrate
- internal epithelia maintains constant flow via peristalsis(wave like contractions movement in gut) , cilia ( The mucociliary cascade) or fluid (salivia) where coughed up
alarms
- tissue resident macrophages are sentinels of infection
fast accurate and specific - big eater
- protrol tissue and triggers response
eaten and alarm raised by producing pulse of distrubutal signals - cytokines ie. chemokines- proteins call in help from wbcs
-vasodilation (widening of blood vesssels and loosen junctions between cells so cells can get out and help) and increased vascular permeability cause redness and swelling, inflammatory cells migrate into tissue releasing inflammatory mediators that cause pain
first responders
neutrophils = respond to cytokines and damage signals and respond to atp which normally inside cell
- eat and destroy = phagocytose
- degranulation = release antimicrobial substances to kill pathogens
NET formation = neutrophils can form whoch traps and neutralises DNA
and then apoptosis
messangers
cells of immune system constantly communicate but key vertebrate immune system is dendritic cell = extensions, coordinators of systemic injury
- feed with foreign pathogen and consumes/digests to kill to breakdown proteins to tell immune system what to do - t cells
- antigen presenting at the lymph node = dendritic cells migrate to lymph node/ draining point, where wbcs get to see blood system, tells circulating cells trouble to trigger adaptive immunity
innate immune vs adaptive
innate = slow, evolutionarily old, relatively non specific, no specific memory, mostly driven by myeloid cells
adaptive = slower, found in verterbrates, specific, memory, driven by lymphoid cells
lymphocyte formation
wbc bone marrow = lymphoid (adaptive) or myleoid route (innate)
t cells
arise in bone marrow
- mature in thymus and adopt final function
- helper t cell = express TCR and recognise antigen, roam and engage and trigger t cell help process, talk to APCS and dendritic cells and wait for matching t cell and differentiates to raft of dif options: role is to secrete cytokines to coordinate broader immune response
th1 = stimukates cytotoxic t cells to proliferate
th2= cells stimulate b cells to proliferate
- cytotoxic t cells = cells that kill other cells via releasing killer blow, all cells have MHC and infection displayed as peptides on MHC, if match they kill
t cells discriminated by
- surface markers ie. proteins
CD8 = cyto, CD4 = helper
-transcription factor expression
FOXP3 = regulatory t cells, Tbet = helper
= can use flow cytometry via staining
or transgenics
b cells
b cells arise and mature in bone marrow and stimulated to release antibodies
- come in different isotypes with different functions e.g. IgG antibodies stimulate phagocytosis
diversity of immune cells
genes encoding antibodies and t cell receptors are modular
no two t cell are the same
