Exam 1 Flashcards
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What is the myeloid tissue and the derivatives?
RBCs, platelets, granulocytes, megakaryoblasts, monocytes, etc.
tissue is BM
What are the lymphoid tissues and derivatives?
thymus, spleen, lymph nodes
Where do plasma cells and memory lymphocytes reside?
bone marrow
When is the liver important in blood cell production?
month 3 of development until shortly before birth
Why are placental HSCs important?
they can be used in future therapy via transplantation
What is the earliest fetal site of blood cell production?
mesonephros
What is the final developing site of fetal blood cell production?
bone marrow
What general area is hematopoietically active in post-pubertal adults?
axial skeleton
What are hemtopoietic stem cell markers?
cKIT+, Sca-1+, LIN-
Why are differentiated cells easier to identify than stem cells based purely on markers?
they become more specific with differentiation
What are the two essential features of hematopoietic stem cells?
pluripotency and capacity for self renewal
What can stress and G-CSF do to stem HSCs?
mobilize them into peripheral blood
How can unregulated clonal expansion occur?
lack of GF dependence and inability to mature
What is the normal morphology of the bone marrow?
thin-walled sinusoids lined with endothelial cells, the interstitium is filled with HSCs and fat cells
Where are megakaryoblasts found in in normal BM?
next to sinusoids and extend cytoplasmic processes into blood stream to elaborate platelets, also have surrounding precursor RBCs “nurse cells” can give iron to help with Hg synthesis
What is leukoerythroblastosis?
abnormal release of immature precursors into the peripheral blood
What are immature WBCs in the peripheral blood known as and what should be done?
they are called blasts and should be worked up for neoplasia, can be differentiated with cell markers
How is bone marrow fat useful in identifying hematopoietic tumors?
ratio is normally 1:1 fat to hematopoietic elements, this decreases with tumors
What are the two broad categories of WBC disorders?
proliferative is increased which can be reactive or neoplastic and leukopenias are decreases,
What causes reactive proliferation of WBCs?
infections and inflammation
What are the common causes of lymphopenias?
HIV infections, glucocorticoid or cytotoxic drug therapy, malnutrition, acute viral infections
How do viral infections cause lymphopenia?
redistribution phenomenon where T cells are sequestrated in the lymph nodes
What are neutropenia and agranulcytopenia?
low and nearly absent neutrophils, respectively
What are the main mechanisms by which neutropenia is caused?
inadequate/inaffective granulopoiesis or increased destruction/sequestration in the periphery