(MLS 428) Cell Morphology - Module 3 (Cutoff module for midterm exam) Questions With CompleteSolutions

acanthocyte correct answer: "thorn cells"/spur cells - small spherical cells with thornlike projections - have no central pallor; have membranes with free cholesterol accumulating preferentially in outer bilayer, leading to decreased fluidity anemia correct answer: insufficient number of RBCs, characterized by inadequate tissue oxygenation ankyrin correct answer: large protein serving as high-affinity binding site for attachment of spectrin to inner membrane surface - binds to spectrin near region involved in dimer-tetradimer associations BFU-E correct answer: Burst-forming-unit-erythroid (erythroid progenitor) - regulated primarily by cytokine IL-3 or GM-CSF/CSF2, released by local microenvironmental stromal cells -- have low concentration of erythropoietin receptors and are thus insensitive to EPO -- except in high concentrations - defined as progenitor cells that give rise to a "burst" or multifocal colony of cells in an in vitro colony assay in 10-14 days; colony consists of several hundred to several thousand Hgb-containing RBC precursors -- maturation of BFU-E gives rise to CFU-E progenitor - positive for CD34, progenitor cell marker - high proliferative potential, low cycling rate CFU-E correct answer: colony-forming unit-erythroid (erythroid progenitor) - undergoes only a few cell divisions; gives rise to a single, discrete colony of 8-64 identifiable cells within 7 days of culture -- CFU-E's have high concentration of EPO membrane receptors and, thus, they respond to lower concentrations than BFU-E does -- CFU-E is immediate precursor of earliest morphologically-recognizable erythroid precursor -- the pronormoblast - CFU-E begins expressing surface proteins characteristic of erythroid lineage, including: glycophorin A, Rh antigens -- in a subset of CGU-E, the ABH and Ii antigens cyanosis correct answer: a blue discoloration of skin due to an increased concentration of deoxyhemoglobin in blood - certain oxidant drugs can interfere with methemoglobin reductase and cause abnormally high methemoglobin, resulting in cyanosis erythron correct answer: refers to the totality of all stages of erythrocyte development -- including precursor cells in marrow, mature cells in peripheral blood, and vascular areas of specific organs (such as the spleen) erythrocytosis correct answer: excess # of circulating RBCs -- has no adverse rx. on pulmonary gas exchanges erythroblast correct answer: nucleated erythrocytes in the bone marrow are collectively called this erythroblastic islands correct answer: distinctive histologic configurations in which erythropoiesis occurs - consist of concentric circles of developing erythroblasts and reticulocytes clustered around a central macrophage