front 1 What are the 4 steps of leukocyte trafficking (in order)? | back 1 Rolling → Activation → Firm adhesion → Diapedesis |
front 2 Where does leukocyte egress occur? | back 2 Post-capillary venules |
front 3 Why are post-capillary venules ideal for leukocyte egress? | back 3 Slow blood flow, thin walls, high adhesion molecules, easier cell passage |
front 4 What are High Endothelial Venules (HEVs)? | back 4 Specialized lymph node vessels that allow lymphocyte entry from blood |
front 5 What molecules are involved in rolling? | back 5 Selectins (L, E, P) and Sialyl Lewis X |
front 6 What molecules are involved in activation? | back 6 Chemokines and chemokine receptors |
front 7 What molecules are involved in firm adhesion? | back 7 Integrins and ICAMs |
front 8 What molecules are involved in diapedesis? | back 8 Integrins, ICAMs, and junction adhesion molecules |
front 9 What are selectins? | back 9 Adhesion molecules that mediate leukocyte rolling |
front 10 What do selectins bind to? | back 10 Carbohydrate-containing mucin-like molecules |
front 11 What are lectin domains? | back 11 Carbohydrate-binding regions of proteins |
front 12 What is Sialyl Lewis X (SLeX)? | back 12 Carbohydrate ligand that binds selectins |
front 13 What are chemokines? | back 13 Small signaling proteins that guide leukocyte movement |
front 14 What are key characteristics of chemokines? | back 14 Small, form gradients, bind GPCRs |
front 15 What are chemokine receptors? | back 15 7-transmembrane GPCRs on leukocytes |
front 16 What are integrins? | back 16 Adhesion receptors for firm binding |
front 17 What is the structure of integrins? | back 17 Alpha and beta subunits |
front 18 What do integrins bind to? | back 18 ICAMs and extracellular matrix proteins |
front 19 What is inside-out signaling? | back 19 Chemokines activate integrins to increase binding affinity |
front 20 What are ICAMs? | back 20 Immunoglobulin superfamily adhesion molecules |
front 21 What do ICAMs bind to? | back 21 Integrins |
front 22 What is the role of ICAM-1? | back 22 Adhesion during inflammation |
front 23 What is the role of ICAM-2? | back 23 Leukocyte trafficking |
front 24 What is the role of ICAM-3? | back 24 T cell interactions |
front 25 What is the function of L-selectin? | back 25 Helps lymphocytes enter lymph nodes |
front 26 What is the function of P-selectin? | back 26 Initiates leukocyte rolling |
front 27 What is the function of E-selectin? | back 27 Helps leukocytes roll at inflamed tissue |
front 28 What is αMβ2 (Mac-1)? | back 28 Integrin for firm adhesion and migration |
front 29 What are sentinel cells? | back 29 Tissue-resident cells that detect infection |
front 30 What are examples of sentinel cells? | back 30 Macrophages, dendritic cells, mast cells |
front 31 What do sentinel cells release? | back 31 Cytokines and chemokines |
front 32 What are the consequences of sentinel cell activation? | back 32 Recruit leukocytes, increase adhesion molecules, initiate inflammation |
front 33 What is the purpose of myeloid cell migration? | back 33 Move to sites of infection |
front 34 What is the purpose of lymphocyte migration? | back 34 Immune surveillance |
front 35 How does antigen arrive at lymph nodes? | back 35 Free antigen via lymph, dendritic cells, subcapsular macrophages |
front 36 How do lymphocytes circulate? | back 36 Blood → lymph node → lymph → blood |
front 37 What is in the cortex of a lymph node? | back 37 B cells |
front 38 What is in the paracortex? | back 38 T cells |
front 39 What is in the medulla? | back 39 Plasma cells and macrophages |
front 40 What is the role of chemokines in lymph nodes? | back 40 Guide cells to correct zones |
front 41 How do T cells meet antigen-presenting cells? | back 41 Both follow CCL19/CCL21 via CCR7 to the paracortex |
front 42 What is the fibroblastic reticular cell (FRC) network? | back 42 Scaffold guiding T cell movement |
front 43 What do FRCs secrete? | back 43 CCL19 and CCL21 |
front 44 What is S1P? | back 44 Lipid signaling molecule high in blood and lymph |
front 45 What is S1PR1? | back 45 Receptor for S1P on lymphocytes |
front 46 What is the function of S1P | back 46 S1PR1? / Controls lymphocyte exit from lymph nodes |
front 47 How does S1P signaling work? | back 47 Cells follow gradient from low (node) to high (blood) to exit |