Term
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Definition
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Term
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Definition
| type of leukocyte that has an antigen specific receptor |
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Term
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Definition
| clear liquid through which lymphocytes can move (from periphery to heart) lymph tissues are aggregates of lymphoid cells |
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Term
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Definition
| thin walled vessels with valves (fluid is moved by adjacent muscles and gravity. The flow is unidirectional; periphery to the heart. Enters the pLN via the afferent lymphatics (and empties into the blood at a thoracic duct) |
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Term
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Definition
| where lymphocytes and lymph return to blood |
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Term
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Definition
| where naive lymphocytes enter lymph nodes from |
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Term
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Definition
| how antigens from sites of infection reach lymph nodes |
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Term
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Definition
| starts in tissue and lymphocytes can drain out of tissues in this clear extracellular liquid and drains out to clear vessels that have valves |
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Term
| movement of adjacent muscles |
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Definition
| keeps movement of lymph through body, flow is from periphery back to heart. At heart the lymph joins the blood supply and circulation of blood can go back around |
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Term
| Lymph drains to vessels by ______ by __________ |
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Definition
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Term
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Definition
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Term
| 3 categories of lymphoid tissues |
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Definition
1) primary
2) secondary
3) teritary |
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Term
| explain the 3 types of lymphoid tissues |
|
Definition
1) Primary (where the b and t cells are educated/generated)
a. Bone marrow and thymus (sites of b and t cell generation)
2) Secondary
a. Collection points for circulating lymphocytes. Sites of interaction between b cells, t cells and APCs (where immune response begins)
i. Spleen (systemic infections), plays role in filtering blood
ii. Encapsulated lymph nodes (local infections) ,
iii. Peyer’s patches (small intestine)
3) Tertiary
a. MALT (mucus associated lymphoid tissue)
i. Inducible, not encapsulated (develops during inflammation) this tissue is developed in response to inflammation |
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Term
|
Definition
(where the b and t cells are educated/generated)
Bone marrow and thymus (sites of b and t cell generation) |
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Term
| Secondary lymphoid tissue |
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Definition
a. Collection points for circulating lymphocytes. Sites of interaction between b cells, t cells and APCs (where immune response begins)
i. Spleen (systemic infections), plays role in filtering blood
ii. Encapsulated lymph nodes (local infections) ,
iii. Peyer’s patches (small intestine) |
|
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Term
| what are the 3 parts of the secondary lymphoid tissue type |
|
Definition
i. Spleen (systemic infections), plays role in filtering blood
ii. Encapsulated lymph nodes (local infections) ,
iii. Peyer’s patches (small intestine |
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Term
|
Definition
includes MALT (mucus associated lymphoid tissue)
i. Inducible, not encapsulated (develops during inflammation) this tissue is developed in response to inflammation |
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Term
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Definition
| mucus associated lymphoid tissue |
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Term
| where are primary lymphoid tissues made? |
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Definition
Bone marrow
b cell development takes place, get pluripotent HSC that starts out in bone marrow; and becomes common lymphoid progenitor (b cells develop level of pre b cells (undergo VDJ rearrangement in bone marrow) once they reach stage of maturation they leave and enter blood supply and go to peripheral lymph nodes of secondary lymph tissues |
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Term
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Definition
| place where T cell development occurs(positive and negative selection) |
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Term
| characteristics of thymus |
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Definition
-multi-lobed nodular organ located posterior to sternum
-very large in first years of life (maximum size at puberty)
-becomes smaller during involution (degenerative process when connective tissue fibers and fat cells replace the functional (parenchyma) tissue (Hormonal control)
-some residual pieces of functional tissue remain
-evolution of thymic involution is poorly understood |
|
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Term
| what type of lymphoid tissue is the thymus? |
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Definition
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Term
| corticomedullary junction |
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Definition
Early progenitors leave bone marrow and enter thymus by these
(thymus divided into 2 major areas (cortex and medulla), and enter through thymus junction between those two parts. |
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Term
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Definition
| important diagnostic feature, only the thymus tissue has these structures |
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Term
| Progenitors move from bone marrow to thymus where they become ______ t cells. |
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Definition
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Term
| when naïve T cells become mature, what are they? and where do they go? |
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Definition
CD4+ or CD8+
leave the thymus via the blood and eventually find their way to lymph nodes (where primary immune response begins), mucosa-associated lymphoid tissue, or spleen. |
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Term
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Definition
| place of t cell positive selection, immature thymocytes. TcR: rescued from death |
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Term
|
Definition
| place of t cell Negative-selection, epithelial cells AIRE, dendritic cells, macrophages-remove apoptotic cells |
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Term
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Definition
| Thymic cortical epithelial cells expresss this |
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Term
| Medullary epithelial cells are also called |
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Definition
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Term
| positive selection of t cells |
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Definition
| immature thymocytes are rescued from death by signal from t cell receptor and they get signals from MHC molecules which are expressed by cortical epithelial cells |
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Term
| Cells that get survival signals then move into medulla area where they undergo _____________ |
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Definition
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Term
| Most negative selection is signaled by what cells which are in medullary area? |
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Definition
|
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Term
|
Definition
| are involved in removal of dying cells (ones that see antigen in cell fashion with too high affinity, they undergo apoptotic cell death), |
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Term
|
Definition
| cells can provide most of the antigens, but some antigens are not presented by these cells so epithelial cells secrete AIRE (auto immune regulator) that lets them see additional antigens that would not have otherwise been able to be recepted |
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Term
| What are the 3 groups of the secondary lymphoid organs (sites where immune response begins?) |
|
Definition
1) Encapsulated lymph nodes
2) Spleen
3) Peyer’s Patch (do not have a capsule) |
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Term
| primary functions of secondary lymphoid organs |
|
Definition
a) Promote interactions between t cells and APCs (usually dendritic cells)
b) Filter blood and lymph (spleen and lymph nodes) peyers patch is more important to immune response in gut
c) Provide survival factors for naïve b and t cells (without these survival factors, the naïve t cells will not live) |
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Term
| development of secondary lymphoid organs |
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Definition
| needs special type of cells, lymphoid tissue inducer cells, which responds to Lymphotoxin-alpha |
|
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Term
| what types of cells respone to lymphotoxin-alpha in secondary lymphoid organs? |
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Definition
| lymphoid tissue inducer cells |
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Term
| organization of secondary lymphoid organs |
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Definition
is maintained by chemokines (in inflammation). Active process requires G protein coupled receptors
Additional reorganization occurs during inflammation (ex. Development of germinal centers) |
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Term
| development and organization of secondary lymphoid structures requires what family members? |
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Definition
| TNFR (tumor necrosis factor receptor) |
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Term
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Definition
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Term
|
Definition
|
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Term
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Definition
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Term
| Lymphoid tissue inducer cell comes out of the liver during what stage of life? |
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Definition
|
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Term
| what does lymphoid tissue inducer do |
|
Definition
this circulates in blood until they find stromal cells that have lymphotoxin receptor so lymphotoxin is either membrane bound or soluble
-When cells find cells that have lymphotoxin receptor, that’s where the encapsulated lymph nodes begin to develop
So Peyers patches develop (not encapsulated ) |
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Term
| When stromal cells are signaled by lymphotoxin, what happens? |
|
Definition
| they start to produce chemokines that attract immature b cells that provide more lymphotoxin |
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Term
| If you don’t have the lymphotoxin, what happens in spleen and lymph nodes? |
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Definition
| you will not have any uncapsulated lymph nodes on animal models and the spleen is very disorganized (it must be present to organize spleen) |
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Term
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Definition
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Term
| In the SLO, there are 3 zones; |
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Definition
1) Outer Zone – antigen sampling (APC rich)
2) B cell activation zone (in resting conditions: follicle/ during inflammation it contains: germinal centers)
3) T cell activation zone (depending on which tissue you are looking at)
a. Called the Paracortex (in the lymph nodes)
b. Called the T cell areas surrounding arterioles (in the spleen)
c. Called the Interfollicular zone in (in the Peyer’s patches) |
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Term
| What does outer zone of SLO do? |
|
Definition
| antigen sampling (APC rich) |
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Term
| What happens in B cell activation zone of SLO? |
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Definition
| (in resting conditions: follicle/ during inflammation it contains: germinal centers) |
|
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Term
| What are the 3 types of T cell activation zones in the SLO (depending on which tissue you are looking at) |
|
Definition
a. Called the Paracortex (in the lymph nodes)
b. Called the T cell areas surrounding arterioles (in the spleen)
c. Called the Interfollicular zone in (in the Peyer’s patches) |
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Term
| function of peripheral lymph nodes (encapsulated) |
|
Definition
Filter lymph and promote interactions between lymphocytes and APCs (antigen presentation); very important during local infections of peripheral tissue
Naïve t cells (ones that leave the thymus but have not yet seen the t antigen) continually circulate between the pLN via the blood and the lymphatics (survival factors) ; if they find an Ag that is specific to their receptor they will then undergo maturation and develop into an effector cell |
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Term
| Fibrous capsule of peripheral lymph nodes |
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Definition
| subdivided into different compartments by inward pointing trabeculae |
|
|
Term
| what are the 2 basic regions of the fibrous capsule of the peripheral lymph nodes? |
|
Definition
1) Cortex: populated mainly with lymphocytes
a. B cell follicles
b. T cell areas
2) Medulla: labyrinth of lymph-draining sinuses which contain many plasma cells and macrophages which are attached to reticular fibers (function of medulla is not very well understood |
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Term
|
Definition
this is the place where lymph enters through in the lymph node.
it is lined by metallophilic macrophages which are critical for antigen sampling (filters lymph) |
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Term
| Cortex area of lymph node |
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Definition
| where b cell follicles are |
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Term
| Deep cortex of lymph nodes |
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Definition
|
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Term
|
Definition
| a depression where vessels and ducts end up to the organs (so organs have a hilus as well as peripheral lymph nodes) |
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Term
|
Definition
| required for development of FDC's |
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Term
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Definition
| cells of the immune system found in lymph follicles of secondary lymphoid organs and tertiary lymphoid organs.[1] They are probably not of hematopoietic origin, though they look similar to true dendritic cells due to their filiform dendritic processes, but are of stromal, mesenchymal origin. |
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Term
|
Definition
| Follicular dendritic cells |
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Term
| efferent lymph joins blood at the |
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Definition
|
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Term
|
Definition
| afferent lymph enters lymph node through this |
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Term
| efferent lymph exits through the |
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Definition
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Term
|
Definition
| The lymph will bring in Ag’s from periphery where they can interact with t cells. T cells enter the encapsulated lymph nodes through high endothelial venules which are small blood vessels |
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Term
| Naïve t cells come into lymph node from blood into the HEV’s and go into t cell zone, and in the t cell zone, they will find these cells: |
|
Definition
| interdigitating dendritic cells cells (which are immature APC’s) at this point we don’t have an immune response so most dendritic cells are immature |
|
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Term
|
Definition
| has most naïve b cells but there are also follicular dendritic cells and cd4 t cells. |
|
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Term
| Are Follicular dendritic cells of hematopoeitc stem cell origin? |
|
Definition
No!
although they have a dendrite tight morphology they are not really dendritic cells. They cannot process antigen from MHC class 2 (all they can do is collect new complexes which are antigens coated with antibodies) |
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Term
| Can FDCs process antigen from MHC class II? |
|
Definition
NO!
(all they can do is collect new complexes which are antigens coated with antibodies) |
|
|
Term
| What type of substance do b cells make during development of lymph nodes? |
|
Definition
|
|
Term
| why is TNF-alpha important? |
|
Definition
1) for making lymphotoxin during development of the lymph nodes
2)for organization of lymph node
3)for development of FDC’s (follicular dendritic cells |
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Term
|
Definition
| granular cells surrounded by epithelial cells |
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Term
|
Definition
| where the lymph vessels enter the lymph node |
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Term
|
Definition
Paracortex: (the t cell area in the encapsulated lymph nodes); where circulating lymphocytes enter the pLNs via HEV and interact with DCs (naïve t cells enterby HEV with interdigitating dendritic cells)
B- cell area= primary follicles and germinal centers (after antigen challenge). Follicular DC capture immune complexes on their surface for recognition by b cells |
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Term
|
Definition
| a part of the cortex (the t cell area in the encapsulated lymph nodes); where circulating lymphocytes enter the pLNs via HEV and interact with DCs (naïve t cells enterby HEV with interdigitating dendritic cells) |
|
|
Term
| what is the b cell area composed of? |
|
Definition
| primary follicles and germinal centers (after antigen challenge). Follicular DC capture immune complexes on their surface for recognition by b cells |
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Term
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Definition
| labyrinth of lymph-draining sinuses which contain many plasma cells, and some macrophages and memory t cells. The function of this portion is poorly understood. |
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Term
| The artery divides into branching arterioles which lead to: |
|
Definition
| the capillary bed and HEV (selective entry) |
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Term
| HEV's (High endothelial venules) |
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Definition
| venules that control selective entry into peripheral lymph nodes, and this is different from the spleen (because it is selective entry) |
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Term
| Cells can leave the pLN via two routes: |
|
Definition
1)Post capillary venules near the germinal centers
2)From the medulla to efferent lymph (also joins the blood supply at the thoracic duct) |
|
|
Term
| Naïve t cells constantly circulate between...... |
|
Definition
secondary lymphoid tissues
(peripheral encapsulated lymph node and the spleen) |
|
|
Term
| if naive t cells dont find the antigen what will happen? |
|
Definition
| they will keep moving from one lymph node to another depending on survival signals |
|
|
Term
| If there is an immune response, what happens? |
|
Definition
the local lymph nodes will become enlarged (draining lymph node- where immune response will begin), become enlarged as response to inflammation, (infection leads to immature dendritic cell response to pick up antigen and then carrying it to local lymph node), as it moves to local node it becomes a mature dendritic cell and this activates naïve t cell and the naïve t cell leaves draining lymph node and then can go to other places of body
Infected t cells that have been activated can then go to any part of the body.
Naïve t cells begin their response in organized lymphoid tissues that contain professional APCs |
|
|
Term
| where do Naïve t cells begin their response ? |
|
Definition
| in organized lymphoid tissues that contain professional APCs |
|
|
Term
| Is lymphocyte migration an active process? |
|
Definition
|
|
Term
|
Definition
| chemokines and adhesion molecules-membrane bound molecules; control access into peripheral lymph nodes across high endothelial venules, a selective process, interactions with adhesion molecules is the only way it can enter the peripheral lymph nodes (how t cells know where to go) |
|
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Term
|
Definition
(membrane bound)
-control access to pLN via HEV (selective process)
-Selectins CD62L (tethering and rolling) (form weak adhesions to t cells, so they can stick to walls of vessels)
-Integrins (activated by chemokines) firm adhesion (undergo conformation change) after firm adhesion, they can squeeze between wall and enter the lymph node
-ICAMS intercellular adhesion molecules (compartments for integrins) |
|
|
Term
| what are all the different adhesion molecules involved in lymphocyte migration? |
|
Definition
-control access to pLN via HEV
1) Selectins CD62L (tethering and rolling) (form weak adhesions to t cells, so they can stick to walls of vessels)
2) Integrins (activated by chemokines) firm adhesion (undergo conformation change) after firm adhesion, they can squeeze between wall and enter the lymph node
3) ICAMS intercellular adhesion molecules (compartments for integrins) |
|
|
Term
|
Definition
| These are soluble and have a low MW: Chemical gradient and activate integrins; signal via g protein coupled receptors; set up chemical gradient that t cells can follow. |
|
|
Term
| are lymphocytes motile as they pass through the pLN? |
|
Definition
| YES they are constantly motile |
|
|
Term
| when lymphocytes enter by blood and then exit from pLN, they must down regulate what receptors? |
|
Definition
| regulate Sphinosine 1-phosphate (S1P) receptors via g protein coupled receptors |
|
|
Term
|
Definition
naive and memory t cells enter the lymph nodes from the blood via these
(lymphocytes and DC enter the pLN via these; it is an active process which requires chemokines and adhesion molecules) |
|
|
Term
| Diagram of initiation of immune response broken down in word form: |
|
Definition
| Local lymph nodes get bigger (TNF-alpha) --> (dendritic cells mature) --> chemokines signal --> enters through node --> local lymph nodes undergo extensive remodeling during infections --> t cells get activated --> chemokines get signaled --> PAMPS (pathogen associated molecular patterns recognized by innate immune system) |
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Term
| Organization of secondary lymphoid tissue |
|
Definition
| Begins when there’s an infection, the immune system first recognizes the pathogen associated molecular pattern which induce inflammation. When you get inflammation, you get immature cells out in the periphery that pick up antigens and carry them to local lymph nodes. During this process, dendritic cells become mature and upregulate molecules necessary to activate naïve t cells. Naïve t cells come in to lymph node via HEV’s and they find interdigitating dendritic cells where they become effector cells. Effector cells leave via the lymph which then joins back to the blood and then they can go back to site of infection. During this process, inflammation causes the lymph node to become considerably bigger. |
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|
Term
| b cells undergo positive selection in response to antigen that is collected by what? |
|
Definition
| follicular dendritic cells (FDCs) |
|
|
Term
| Cells that find the correct antigen become: |
|
Definition
| memory b cells and plasma cells |
|
|
Term
| what does an enlarged lymph node with clear germinal center indicate? |
|
Definition
| there is a local inflammatory response |
|
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Term
|
Definition
-secondary lymphoid tissue
-has a very obvious clear capsule, but is quite different from peripheral lymph nodes |
|
|
Term
| primary functions of spleen |
|
Definition
: filters blood (5% cardiac output goes straight to spleen) and recycles iron
Captures and destroys pathogens (that may be circulating in blood) and triggers adaptive immune responses |
|
|
Term
| what type of circulation does spleen have? |
|
Definition
open circulation (slightly different to peripheral lymph nodes bc theres no lymphatics): discontinuous endothelial lining from artery to vein (artieries do not connect directly to vein) blood is released into red pulp area, making it discontinuous)
The blood is filtered as it crosses a fenestrated basement membrane surround the venous sinuses. |
|
|
Term
| diagnostic feature of spleen |
|
Definition
red pulp ( contains large numbers CD8 T cells and plasma cells)
There are no HEV and no afferent lymphatics |
|
|
Term
| average spleen size/weight |
|
Definition
About 4 inches long
Weighs 7 ounces |
|
|
Term
| There are 3 zones of the spleen: |
|
Definition
1) Red pulp
a. 75%
b. Loose tissue between the venous sinuses
2) White pulp
a. B and t cell compartments
b. The t cell zone surrounds the arterioles
3) Perifollicular zone
a. 8%
b. Surrounds the b and t cell zones
The marginal zone surrouds the b cell follicles (but not the t cell zone)
Macrophages trap pathogens in the blood stream. All cells enter the white pulp via the marginal zone |
|
|
Term
|
Definition
| one of 3 zones of spleen; makes up 75%, contains loose tissue between the venous sinuses |
|
|
Term
|
Definition
one of 3 zones of spleen
has B and t cell compartments
-has a t-cell zone that surrounds the arterioles |
|
|
Term
|
Definition
one of 3 zones of spleen
-make up 8%
- Surrounds the b and t cell zones |
|
|
Term
| The marginal zone surrouds the _______ but not the _________ |
|
Definition
b cell follicles
but not the
t cell zone |
|
|
Term
| Macrophages trap pathogens in the blood stream. All cells enter the white pulp via the ____________ of the spleen |
|
Definition
|
|
Term
| Arteries leading to spleen |
|
Definition
| -Arteries hardly anastomose at all. At the terminal end of the capillary is a blind ended structure which is surrounded by concentrically arranged macrophages. Blood cells have to pass through the sheath before reaching the lumen of the sinus. |
|
|
Term
|
Definition
contains discontinuous periarteriolar lymphatic t cell sheath (PALS)
The t cell regions are interrupted by the b cell follicles.
The arterioles branch and terminate at the periarteriolar macrophage sheaths |
|
|
Term
|
Definition
| periarteriolar lymphatic t cell sheaths |
|
|
Term
|
Definition
| All lymphocytes enter the spleen via this space between the b cell and t cell area and this is where the blood is filtered by macrophages; and red pulp HEV are not required (non-selective entry) |
|
|
Term
| blood comes in from the trabecular artery and goes to the __________ |
|
Definition
|
|
Term
| Do arteries near spleen form anastomonses? |
|
Definition
NO, they do not
this means that the same vessel does not branch and rejoin so they have these sort of large areas/sinuses at the end which have macrophages which are important to filter blood. |
|
|
Term
| Once t cells leave marginal zone, where do they go? |
|
Definition
|
|
Term
|
Definition
| interconnecting mesh, with bulb-like extensions and blind ends |
|
|
Term
|
Definition
| they are remarkable for their numerous anastomoses (reconnections between streams that previously branched out). |
|
|
Term
| are there many anastomoses in red pulp in venous blood supply? |
|
Definition
|
|
Term
| Red Pulp is divided into 2 zones |
|
Definition
1) Filtering Zone
a. Loose reticular tissue rich in partially sheathed capillaries and venous sinuses surrounded by circular bands of basement membrane. The arterial blood arrives into cords of red pulp and passes into venous sinuses, where it is forced through the slits formed by the stress fibers and endothelial cells. (Red blood cells cannot pass through these sinuses).
2) Non-filtering areas: no capillaries |
|
|
Term
| Filtering zone of red pulp |
|
Definition
| a. Loose reticular tissue rich in partially sheathed capillaries and venous sinuses surrounded by circular bands of basement membrane. The arterial blood arrives into cords of red pulp and passes into venous sinuses, where it is forced through the slits formed by the stress fibers and endothelial cells. (Red blood cells cannot pass through these sinuses). |
|
|
Term
|
Definition
| this zone of red pulp has no capillaries |
|
|
Term
|
Definition
-a tubular network in spleen and lymph nodes; bundles of collagen fibers surrounded by stromal cells
-small molecules (delivers chemokines and peptides/antigens into lymph node) (not carried by dendritic cells; they are soluble antigens)
-some cells can also enter during inflammation |
|
|
Term
|
Definition
| what part of the conduit system of the spleen is in white pulp supplies (supplies the blood) |
|
|
Term
|
Definition
| this material makes up part of the conduit system in pLN that is surrounded by basement membrane and reticular fibroblasts (supplies the lymph) |
|
|
Term
| what are the 2types of mucus-associated lymphoid tissues (MALTs) : |
|
Definition
| Gut associated lymphoid tissue (GALT) or the Peyer’s Patches |
|
|
Term
| where are Peyer's patches found? |
|
Definition
|
|
Term
| Where are single lymphoid follicles that actually make up inducible tertiary lymphoid tissue found? |
|
Definition
|
|
Term
| is the peyers patch attached to lymphatics? |
|
Definition
no
you don’t get lymph from a capsule bc there is no capsule; |
|
|
Term
|
Definition
-different to encapsulated lymph node
-its not attached to lymphatics
-actually faces in toward the lumen of the small intestine
-there are specialized cells so it has a dome structure (specialized cells, apex of dome brings antigens in from the intestine)
-) these cells actually have a folded surface on them and they can pass antigens all the way through
-At the bottom there are pockets with dendritic cells in them and these dendritic cells pick of Ag’s and bring them to b and t cell areas and sometimes they will end up in afferent lymphatics and then mesenteric lymph nodes (largest lymph nodes ; serve the intestine) |
|
|
Term
| how do T cells enter and exit? |
|
Definition
| enter via HEV and leave via afferent lymphatics (go to mesenteric lymph nodes) |
|
|
Term
| Antigens and microorganisms are transported by what? |
|
Definition
| by M cells (microfolds on their luminal surface to DC which are located in the dome. |
|
|
Term
| most immature DCs remain where? |
|
Definition
| in the sub epithelial dome |
|
|
Term
| Upon maturation the DC move where? |
|
Definition
| into interfollicular t cell areas, b cell zone, and draining lymphatics |
|
|
Term
| what is the function of the Peyers patch? |
|
Definition
| specialized site that takes up bacteria and produces immune response |
|
|
Term
| Mucosal associated lymphoid tissues (MALT) |
|
Definition
organized collections of lymphocytes (separate t and b cell zones)
-development is induced/maintained by inflammation (TNFalpha)
-Lymphotoxin is not required (even if animal doesn’t have lymphotoxin and wont have encapsulated lymph nodes however,they can still produce MALT)
-predominantly antigen-experienced t cells
-has 3 sub-types |
|
|
Term
| What are the types of teriary lymphoid tissues? |
|
Definition
1) Mucosal associated lymphoid tissues (MALT)
2) Gut associated lymphoid tissues (GALT) (type of MALT)
3) Nasal associatied lymphoid tissues (NALT) (type of MALT)
4) Bronchus associated lymphoid tissue (BALT) (type of MALT) |
|
|
Term
| Gut associated lymphoid tissues (GALT) |
|
Definition
| Isolated lymphoid follicles in the large intestine (type of tertiary lymphoid tissue and type of MALT) |
|
|
Term
| Nasal associated lymphoid tissues (NALT) |
|
Definition
| type of tertiary lymphoid tissue in respiratory tract (type of MALT) |
|
|
Term
| Bronchus associated lymphoid tissue (BALT)- |
|
Definition
| type of teriatry lymphoid tissue of(respiratory tract) in children (and not very obvious in adults) (type of MALT) |
|
|
Term
|
Definition
| when tertiary lymphoid tissues form at sites of chronic inflammation |
|
|
Term
| what are the characteristics of tertiary lymphoid tissues? |
|
Definition
-not capsulated
-form at sites of chronic inflammation through a process referred to as lymphoid neogenesis
-organized b cell compartments, which contain germinal centers
- t cell compartments in which contain antigen-presenting cells
High endothelial venules through which lymphocytes can enter from blood |
|
|
Term
|
Definition
| part of MALT’s of upper respiratory tract (filter against disease) |
|
|
Term
|
Definition
| ovoid masses of lymphoid tissue situated on either side of the throat |
|
|
Term
| Pharyngeal tonsils (adenoids): |
|
Definition
|
|
Term
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Definition
| at the back of the tongue (act as a filter against disease organisms); often becomes site of infection (tonsilitis) and becomes enlarged. |
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Term
Thymus:
1) Diagnostic features
2) Germinal centers?
3) Circulation
4) Stroma
5) Migrating cells
6) Functions |
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Definition
primary lymphoid tissue
Diagnostic features: poorly developed capsule, has Hassall’s corpuscles
Germinal centers: none
Circulation: HEV; blood efferent lymphatics
Stroma: epithelial reticular cells; few fibers
Migrating cells:lymphocytes
Functions:produces t cells. Not exposed to blood or lymph-borne antigens. No afferent lymph vessels |
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Term
Spleen:
1) Diagnostic features
2) Germinal centers?
3) Circulation
4) Stroma
5) Migrating cells
6) Functions |
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Definition
for primary immune response
Diagnostic features: well developed capsule; red pulp
Germinal centers: present
Circulation: efferent lymphatics; red pulp
Stroma: reticular cells and fibers
Migrating cells: all white blood cells
Functions: systemic infections; filters soluble antigen from blood; phagocytosis; production of antibodies; sequestration of blood cells, reprocessing hemoglobin |
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Term
Lymph Node:
1) Diagnostic features
2) Germinal centers?
3) Circulation
4) Stroma
5) Migrating cells
6) Functions |
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Definition
Diagnostic features: Well developed capsule
Germinal centers: Present
Circulation: afferent and efferent lymphatics; HEV: blood
Stroma: Reticular cells and fibers
Migrating cells: Lymphocytes, plasma cells, macrophages/DC
Functions: Local infections; filters soluble antigen from lymph (rather than the blood); phagocytosis; production of antibodies; clonal expansion of b cells |
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Term
MALT (mucous associated lymphoid tissue)
1) Diagnostic features
2) Germinal centers?
3) Circulation
4) Stroma
5) Migrating cells
6) Functions |
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Definition
Diagnostic features: No capsule (except in tonsils)
Germinal centers: present
Circulation: efferent lymphatics; HEV
Stroma: Reticular cells and fibers
Migrating cells: Lymphocytes; plasma cells
Functions: Protect mucosal tissues (induced during inflammation); production of antibodies to; produce lymphocytes found in lamina propria |
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