lymph Flashcards
2 main features of adaptive immunity, and what they allow
1) specificity and memory
2) it can identify and respond to specific threats and remember previous encounters with them for a prolonged period, providing rapid protection to subsequent exposures
what are the specialised receptor on their cell surface of b and t cells called
B cell receptors (BCR) or T cell receptors (TCR)
where are lymphocytes produced
primary lymphoid organs
what is the process of producing lymphocytes called
lymphopoieses
what are the lympocytes
b and t cells
nk cells
what are the 3 main primary lymphoid tissue
thymus
bone marrow
foetal liver
where does most of our lymphopoeis occur in the uterus
foetal liver
what is specificity provided by
a wide range of unique t cell and b cell receptor
what are the 2 main forms of t cells
cd4 or t helper cells
cd8
where is the primary site of haematopoeisis
bone marrow
what happens when we encounter significant infections or inflammatory events
haematopoiesis increases
where is the b cell repertiore generated
bone marrow
what is a Repertoire
the range of genetically distinct BCRs or TCRs present in a given host – with larger the repertoire the more threats can be recognized.
immature t cells migrate from where to where
migrate from bone marrow to the thymus
what 2 forms of selection do t cells undergo
positive and negative
what happens in positive selection
they see hla molecules on sorrounding cells using tcr
what happens if they can’t see mhc
the tcr has lead to a non functioning t cell receptor
they have to be deleted in case they cause non specific activation
what happens after + slection
- selection
what happens in negative selection
the body checks if the t cell reacts against our own body antigen
what happens if they do
apoptosis
what is the last step
final selection of t cells hat recognise a non self antigen
how is teh thymus output affeted by age
the thymus output declines
how is teh thymus output affeted by age
the thymus output declines
what are secondary lympoid tisusue
where lymphocytes can interact with antigen and other lymphocytes
how are lympoid located around teh body
distributed
how are they connected
by the lymohatic system and the blood
what is the function of teh 2dry lymphoid tissue
to brinf the cells close proximity with the antigen
what layers are the b and t cells found in lymph noid
b cells found on teh outer layer of the lymph node
t cells in the inner layer
what separtaes the spleenfrom other 2ndry lympoid tissue
highly attatched to ateroile circulation so it can filter blood antigen
where is lympoid netweork string
areas sourounding our external facing membrane
where is payers patcher found
below the epithelium of the ileum of the small intestines
what is teh payers patch
specialised secondary lympoid tissue
what is Germinal centre:
anatomically restricted site where B cells undergo mutation and selection to generate high affinity antibodies
why does. the intestines have so many germinal centres
high amount of antigen provided in the form of microbial products from the microbiota of the interstrinal tract
why does. the intestines have so many germinal centres
high amount of antigen provided in the form of microbial products from the microbiota of the interstrinal tract
what does the tonsils comprise of
pharyngeal tubular palantine lingual tonsils
what do the tonsils encircle to create
oral and nasal cavity to create the waldeyer ring
what are the tonsils speacilised for
antigen encounter
why is the function of the epithelial layer
antigen can be sampled directly from the external enviroment
why do the tonsils have large germinal centres
as food, air pass through the ring making it the perfect environment to encounter the foreign antigen on daily basis
how do t celld enter lymph node
extravasation
describe the of extravasation
1) rolling
2) activation
3) arrest/adhesion
4) Transendothelial migration
what provides the chemotactic signal to draw t cells into the secretary lymphoid tissue
ccl21
ccr7
what provides the chemotactic signal to draw t cells into the secretary lymphoid tissue
ccl21
ccr7
how are antigens transported from the site of inflammation to the secondary lymphoid tissue via lymphatics
1) uptake by antigen presenting cells (mostly dendtrtic cell) migrate out of inflammed tissue and traffic to lymph node to t and b cells. interact with t cells
2) the antigen will eventually flow into the lymphatics, and tooken to lymhatic node
what is Antigen presentation
The display of peptides in the major histocompatibility complex I or II proteins such that the T cell receptor can attempt to bind them.
