Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
38 Cards in this Set
- Front
- Back
|
What are the 3 mucosa-associated lymphoid tissues (MALT)?
|
1) tonsils
2) Peyer's patches 3) appendix |
|
|
physical barriers, inflammatory responses, antimicrobial substances are all part of what?
|
- innate immune response
- they are all non-specific |
|
|
What are the 3 antigen presenting cells? What MHC do APCs present? 2 lymphocytes?
|
APCs: 1) macrophages, 2) langerhan's cells (skin) 3) dendritic cells (everywhere)
- APCs present MHC class II (present to T cells) Lymphocytes:B & T (also NK cells part of innate response) |
|
|
Difference between B cells and T cells in terms of antigen presentation?
|
- B cells can bind soluble foreign Ag
- T cells are spoiled and have to have antigens presented to them |
|
|
Presentation to T lymphocytes stimulates: 1) ______ or 2) _______. what is the difference?
|
1) terminal differentiation of cytotoxic T cells (activated killing cells)
2) terminal differentiation of helper T cells to assist B cells to differentiate into plasma cells |
|
|
Cytotoxic T cells target _____ pathogens or ____ cells. With the MHC I complex what do cells present?
|
- intracellular (viruses)
- mutate (cancerous) - present fragments from all endogenous proteins |
|
|
How do cytotoxic T cells kill? What MHC presents to them?
|
- release perforin to open target cell
- secrete granzymes (serine proteases) into the target cell - MHC I |
|
|
B cells and antibody-producing plasma cells target ______ pathogens. MHC II helps to activate
|
- extracellular pathogens
- MHC II - activates T helper & B cell becomes plasma cell |
|
|
Bacteria can be ______ with antibodies and then the ____ receptor can bind phagocytosing cells (macrophage, neutrophil, etc)
|
- opsonized
- Fc receptor |
|
|
The thymus grows out of the ______. ______ is released to recruit thymocytes from bone marrow
|
- pharyngeal arches III & IV
- thymotaxins |
|
|
_____ cells in thymus create a network that supports the thymocytes. They exist because the thymus lacks ______ in b/w thymocytes. What are their 2 functions?
|
- epithelial reticular cells (epithelioreticular cells)
- connective tissue 1) educate thymocytes to become immunocompetent T cells 2) form blood thymus barrier |
|
|
What gives the thymus cortex the starry night sky appearance?
|
- lots of lymphocytic nuclei
- macrophages are the stars within it |
|
|
How are thymocytes educated (pos & neg selection)? Once they leave the thymus they can undergo ______
|
IN CORTEX: epithelioreticular cells present MHC molecule - if poor MHC recognition, thymoctye dies = POSITIVE SELECTION
IN MEDULLA: epithelioreticular cell expresses self peptide - if strongly recognized by T cell then it dies = NEGATIVE SELECTION - terminal differentiation (activation) - by this time they have differentiated into cytotoxic & helper |
|
|
How do T-cells exit the thymus?
|
- via HEV (high endothelial venules)
- selectin molecules are expressed on both - lymphocytes craw through to get out - happens in spleen and lymph nodes but in OPPOSITE direction |
|
|
hassall's corpuscles
|
- structures in thymic medulla unknown function
|
|
|
What happens in the germinal centers of lymphoid nodules? What does diffuse tissue have?
|
- B cell proliferation
- NEVER find a plasma cell in there, b/c actually differentiate in connective tissue - diffuse tissue has the T cells |
|
|
What makes up mucosa? Most lymphocytes are present where?
|
- mucosa: epithelial lining, lamina propria, muscularis mucosa
- below is the submucosa - most lymphocytes present in submucosa |
|
|
How do lymphocytes in tonsils sense a pathogen?
|
- papillae extend from lamina propria into epithelium - cells can crawl up
- pinocytosis allows cells to sample environment |
|
|
What are M cells?
|
- micofold cells: specialized for sampling
- extracellular invagination of basal surface, allows lymphoid cells to get close to surface - pinocytosis to bring in tact antigens to B & T cells |
|
|
What are the two mechanisms to generate lymph flow in the lymphatics?
|
1) skeletal muscle contraction external to lymphatics
2) smooth muscle contraction in lymphatic wall |
|
|
What are two mechanisms of lymph resorption?
|
1) inter-endothelial flow (down intraluminal pressure gradient)
2) vesicle transcytosis |
|
|
What does the lymph node hilum contain?
|
- artery, vein, efferent lymphatic
|
|
|
In the lymph nodes, where do afferent lymphatics feed in? Where are nodules found? Where is the diffuse tissue found?
|
- CT capsule
- found in outer cortex - diffuse tissue is found in inner para cortex |
|
|
What is found in the medullary cord? The medullary sinuses have ______ epithelium
|
- reticular fibers, plasma cells, lymphocytes, fibroblasts, neutrophils
- discontinuous |
|
|
What is the difference between splenic and medullary sinuses?
|
- splenic do not have reticular fibers in the sinus
- have blood instead of lymph |
|
|
In the lymphatic system deep to the CT space there is a _____ sinus. It is continuous with the ______ sinus, that is continuous with the medullary sinus.
|
-subcapsular
- trabecular sinus |
|
|
Lymph system: outer cortex is rich in ___ cells, inner (para) cortex is rich in ___ cells, and medullary sinus is rich in _____ cells.
|
- B
- T - Plasma cells |
|
|
You will never see ______ in the germinal center. You will find these in the ______ cords.
|
- plasma cells
- medullary |
|
|
What are the 3 mechanisms to assure lymph-lymphocyte/APC interaction?
|
1) sinuses are lined by discontinuous endothelium
2) reticular fibers traverse sinuses 3) afferent lymphatics outnumber efferent (bottlenecking) |
|
|
Where do HEV exist? What happens here? What do the porin channels do? How do lymphocytes roll on the HEV wall?
|
- inner para cortex
- this is where lymphocytes escape blood to enter lymph node - porin channels concentrate the lymph - get fluid back into artery - roll on wall via 1) selections initial adhesion 2) integrins stabilize/strengthen adhesion |
|
|
What is the paracortical reaction?
|
- when you have viral infection - cytokines release into blood --> lymphocytes express more selectin --> stick & come through HEV
- activated HEV (post-capillary venules) - bring more cells in than are leaving --> swelling of lymph node - happening in the inner (para) cortex |
|
|
what happens in HIV?
|
- HIV infects CD4 cells --> cytotoxic T cells attack CD4 cells
- helper T cels (CD4) cannot help B cells differentiate into plasma cells - humoral immunity is decreased |
|
|
What is lymphoma? Difference between Hodgkins & non-Hodgkins? Reed-sternberg cells present in which one?
|
- lymphoma - solid tumor of lymphatic system
- reed-sternberg cells diagnostic of hodgkins lymphoma |
|
|
Difference between white and red pulp in the spleen?
|
- white pulp: packed with lymphocytes
- red pulp: where all the blood is |
|
|
What happens in the trabecular artery of the spleen? What does this artery become when it loses it's CT? What is it surrounded by? When arteries come off of this what do they end in?
|
- artery lumen pulls through connective tissue which is part of trabeculum
- artery gets surrounded by lymphocyte = central artery --> has periarterial lymphatic sheath (PALS) - arteries coming off end in the marginal zone that has reticular fibers |
|
|
In addition to reticular fibers, the marginal zone also has _______ & _______
|
- marginal zone macrophages
- metallophilic macrophages - these cells phagocytose matter in blood & capture pathogens to present to T cells |
|
|
What is the artery that begins after the central artery? What happens here?
|
- pennicillar artery
- has macrophage sheath, blood is then dumped into red pulp cords |
|
|
stave cells
|
- filtration slits in the red pulp splenic sinuses - b/c look like barrel
- when bood gets dumped into pulp cords has to travel through filtration slits to get into venus sinuses |
