all blood cells (including cells of immune system) arise from hematopoietic stem cells (HSC) that reside in the bone marrow -very hard to find and locate
what are the major lymphoid organs?
bone marrow, thymus, lymph nodes, spleen, peyer's patches
what is the breakdown of components of the blood?
50% plasma (factors, globulins, proteins, etc.) 50% red and white blood cells
what are the polymorphonuclear granulocytes?
neutrophils, eosinophils, basophils
what are the mononuclear granulocytes?
monocytes and lymphocytes
describe flow cytometry:
cells in suspension are stained with a number of different antibodies
cells are run through flow cytometer and fluorescence from a given cell is recorded
flow cytometry also allows to sort cells depending on the markers expressed
flow cytometry can be used to count cell numbers, phenotyping of cells and cell sorting
what are the 2 ways for cells to die?
necrosis and apoptosis
what is necrosis?
morphologic changes that accompany death of individual cells or groups of cells and that release large amounts of intracellular components to the environment, leading to disruption and atrophy of tissue
what is apoptosis?
morphologic changes associated with programmed cell death, including nuclear fragmentation, blebbing, and release of apoptotic bodies which are phagocytosed -does not damage surrounding cells
what bcl-2 gene do?
what does the bax gene do?
-oppposes bcl-2 -promotes apoptosis
what does the bcl-XL gene do?
what does bcl-XS gene do?
-opposes bcl-XL -promotes apoptosis
what does the capsase gene do?
what does the fas gene do?
describe homeostasis in the immune system:
homeostasis of cells can be passive (no-density dependent proliferation or death) or active (proliferation or death rates are density-dependent)
production of neutrophils is likely to be . . .
production of memory t cells is likely to be . . .
regulation of homeostasis:
in general, bone marrow has the capacity to increase the production of different cell types
what are monocytes?
-have limited phagocytic activity (must be activated) -relatively short lifespan -found in blood
what are macrophages?
-found in tissues -remove dead/dying cells -deal with infections -high phagocytic activity -can be activated by T-helper cells -short lived (2-3 weeks)
what are neutrophils?
-found in blood -migrate to tissues -kill cells dying from necrosis -high phagocytic activity -important in initial control of infection (bacterial)
what are eosinophils?
-respond to parasitic infections (create pores and damage membranes) -release histamine (allergic reactions) -found in blood /tissues
what are mast cells?
-major mediators of all reactions -express high levels of Fc receptors -found in mucosal tissues especially lung -release histamine
what are dendritic cells?
major professional antigen presenting cells
what are the four types of dendritic cells?
what are Langerhans cells?
reside in the skin, migrate to lymph nodes following local inflammation
what are interstitial cells?
-lymphoid (CD8+) and myeloid (CD11b+) -reside in lymph nodes and spleen
what are plasmacytoid cells?
-reside in the blood -produce large amounts of type I interferons following (viral) infections
what are follicular DCs?
-form structural basis of lymph nodes -help to capture antigen and drive affinity maturation of B cells
describe activity of dendritic cells:
-prior to activation, are able to phagocytize invading pathogens -upon activation, express high levels of MHC class I and II (ligands for t cells) -express high levels of costimulatory molecules
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