immune cells and organs Flashcards
(18 cards)
list cell types in immune system
T lymphocytes
APC
B lymphocytes
how do you distinguish between immune cells
cant distinguish with microscope
use (cluster of differentiation) CD receptors - specific antigens on surface - have their own function
T lymphocytes CD 3 4 8 - all CD3 2/3 CD4 1/3 CD8
B lymphocytes CD 19 20
T lymphocyte function
CD4 + helper - cytokines
CD8+ cytotoxic - lyse and cytokines
recognised processes antigen (MHC)
B lymphocyte function
effector - produce antibodies
recognise intact antigen
have surface antigen receptor
MHC class 2
APC function
present processed antigen to T lymphocytes
dendritic, b lymphocytes, activated macrophages.
What is lymphocyte recirculation
lymphocytes exit primary lymphoid tissue and enter blood
circulate between lymph, lymph node/spleen (secondary lymphoid tissue) and blood
why is lymphocyte circulation important
so that it has a higher chance of meeting its specific antigen - initiating an immune response.
explain the steps of extravasation of naïve T cells into lymph nodes
travel on endothelial cells of HEV chemokine bind lymphocyte receptor integrin change conformation - high affinity binding stop rolling migrate through endothelia
recall the primary lymphoid organs
where lymphocytes are produced - LYMPHOPOIESIS
bone marrow
thymus [develop]
recall the secondary lymphoid organs
where lymphocytes meet antigen and other lymphocytes
spleen/lymph node/Mucosal associated lymphoid tissue (malt)
what is the structure of the thymus
bilobular
septa separate lobules
cortex and medulla
Hassall’s corpuscle - fibroblast cells - regulatory T cells develop
what is the structure of bone marrow
fat globules
red marrow produces blood cells
yellow marrow - fat
What is the lymphatic system
drainage system - antigens collected and filtered through nodes
Structure of lymph node
afferent and efferent lymphatic vessel - filtration system - allow time to function
lymphoid follicles - aggregate of mainly B cells
germinal centre - dark area in follicle - high proliferation of B cells
HEV [except spleen] - cell enter lymph node - b periphery, t centre [chemokines - chemotaxis]
structure of spleen
red and white pulp
phagocytes
white pulp immediately around artery
primary follicles
structure of epithelial
physical barrier
most immune cells in MALT - likely site of infection because of thin layer
structure of GALT
microfold cell - antigen from gut to lymphocytes
peyer’s patch - aggregate of follicles
features of cutaneous tissue
dendritic - capture antigen and move into lymph node
