BIO 447 Lecture Notes - Lecture 14: Pharynx, Stratified Squamous Epithelium, Lymphoblast
Document Summary
Small lymphocyte (t or b cell) undifferentiated, prior to antigen activation. Blast cell (t or b cell) undifferentiated, primitive blood cell. Cell enlarges, nucleus active in dna synthesis. Extensive golgi because it makes/secretes lots of antibodies. The blast and plasma cell are both twice the diameter (4x size) of lymphocyte. Intitially produced: bone marrow, migrates into bloodstream and lymph organs (to meet antigens) Clone types: plasma/effector cells antibody factories, mass produced, memory cells - circulate long-term, create immunological memory. Allow for rapid response next time around. Intitially produced: bone marrow: undergo differentiation and acquire secondary characteristics (thymus, undergo a selection process to eliminate cells that cannot separate self/non-self (positive/negative selection) lymph nodes. Positive selection: tests ability of mhci and mhcii to distinguish self/nonself must bind only self-mhc molecules. Negative selection: self-tolerance; tests binding of cd4 and cd8: fails if the receptors binds to self immune cells. Primary lymphoid organ selection, edit, educated: thymus.
