Bone Marrow Objectives
Differentiate apoptosis and necrosis.
Apoptosis is programmed cell death. Cells are removed from circulation and die in a controlled manner. Necrosis is unplanned or uncontrolled cell death. This occurs in circulation. Intracellular contents are exposed to the vasculature.
List the information gained from bone marrow aspirates and biopsy specimens.
Aspirate: cell examination, population examination Biopsy: bone marrow structure/architecture
Define hematopoiesis.
Continuous, regulated process of blood cell production that includes cell renewal, proliferation, differentiation, and maturation.
Determine which cell lines mature in the bone marrow.
Erythroid, megakaryocytic, myeloid, lymphoid
List indications for bone marrow examinations.
Evaluate hematologic disorders Stage lymphoproliferative disorders Investigate fever of unknown origin
Specify sites for bone marrow aspirate and biopsy collection.
Iliac crest Sternum Vertebrae Proximal end of large bones
Identify where adult hematopoietic tissue is located.
Iliac crest, axial skeleton, vertebrae, sternum, proximal end of large bones, skull, thymus
Relate normal and abnormal hematopoiesis to the various organs involved in the hematopoietic process.
In healthy adults, normal hemaptopoiesis occurs in the bone marrow, with some lymphoid development in the primary and secondary lymphoid organs. In certain disease states, the liver and spleen can take up some hematopoietic processes, but the resulting cells are abnormal.
Identify which forms of hemoglobin will be present at each stage of life.
Intrauterine: Gower 1: ζ2 ε2 Gower 2: α2 ε2 Portland: ζ2 γ2 F: α2 γ2 At birth: F: α2 γ2 A1: α2 β2 Two years through adulthood F: α2 γ2 A1: α2 β2 A2: α2 δ2
Determine the features identified or analyzed under low and high power during a bone marrow exam.
Low power: Assess peripheral blood dilution Find bony spicules and areas of clear cell morphology Obesrve fat-marrow ratio Tumors Estimate megakaryocytes High power: Myelotic and erythrocytic ratio (3:1 is ideal) Differential on 300-1000 cells Abnormal distribution of cells or cell maturation stages
Describe the evolution and formation of blood cells from embryo to fetus to adult, including where hematopoiesis is occurring.
Mesoblastic phase: yolk sac Hepatic phase: liver and spleen Medullary phase: bone marrow
Determine the difference between red and yellow marrow.
Red marrow is hematopoietically active marrow that contains developing blood cells and their progenitors. Yellow marrow is hematopoietically inactive and is composed mostly of adipocytes. During infancy and early childhood, the body consists primarily of red marrow. Over time, red marrow is replaced by yellow marrow through a process known as retrogression. Adults have red marrow only in certain bones.
Understand what occurs to blood flow and red blood cells in the spleen.
Slow transit occurs through the red pulp/splenetic artery. Normal red blood cells have membrane flexibility that allows them to withstand the slow transit. Cells that cannot withstand the slow transit are lysed and removed.
Explain the stem cell theory of hematopoiesis, including the characteristics of hematopoietic stem cells, the names of various progenitor cells, and their lineage association.
The most accepted theory is that all blood cell lineages originate from a single pluripotent hematopoietic stem cell. They are self-renewing. These cells can either be non-committed/undifferentiated, or committed progenitor cells. Committed cells are specific for certain cell lineages
