TBL 14: Bone Marrow Flashcards
What are the different hematopoietic organs from gestation to birth?
Blood islands in the mesoderm surrounding the yolk sac. From 2nd to 7th month of gestation, the liver is colonized by hemangioblast-derived hematopoietic stem cells. From 7th month on, the bone marrow is colonized by these stem cells
What are blood smears good for?
cells details, maturation, differential counts, ratio of myeloid to erythroid cells, morphological changes, detect anemias, leukemias, and myeloma
What are needle biopsies good for?
Panoramic view of bone marrow and normal architecture, bone marrow cellularity (index of hematopoietic cells to adipocytes)
How do autologous and allogeneic bone marrow transplants differ?
Autologous - used in lymphoma where marrow is contaminated. Harvest bone marrow and reinject it after obliterating the remaining stem cells
Allogenic - bone marrow comes from another person who matches MHC
What are the four CFU cells?
erythrocytic, granulocytic-monocytic, lymphocytic, megakaryocytes
The cells of erythropoiesis and the characterization of them
CFU-E, proerythroblasts, basophilic, polychromatophilic, orthochromatophilic, nuclear extrusion, reticulocytes (no central pallor), erythrocyte
What is the role of erythropoietin? How long does erythropoiesis last?
produced in kidneys and it stimulates and sustains erythropoiesis which takes about 7-8 days
Why is hypoxia the principal stimulus for erythropoietin secretion?
Regulation exists as a feedback loop. Hypoxia tells the kidneys that not enough O2 is delivered to tissues so it produces erythropoietin to stimulate the development of more RBCs to increase the blood’s O2 carrying capacity
Why does cytoplasmic color change from blue to reddish pink during erythropoiesis?
The RNA also absorbs the basic stain. Over time, the cytoplasm has less RNA as the nucleus is gone so the cytoplasm changes color
Describe granulopoiesis
CFU-GM, myeloblasts, promyelocytes, myelocytes, metamyelocytes, band cells and lobulation of the horseshoe shaped nuclei completes process
When do neutrophilic, eosinophilic, and basophilic granules become distinct?
Metamyelocytes
Characterize Promyelocytes
large, round nuclei and reddish blue cytoplasmic granules (lysosomes)
Characterize Myelocytes
Nuclei are eccentrically positioned and flattened on one side
Characterize metamyelocytes
The flattened side of the nucleus becomes indented and the granules become distinct
Characterize band cells
progressive deepening of the indentation results in horseshoe-shaped nuclei
What is sepsis and when can it progress to septic shock?
systemic response to infection. Blood poisoning. Infection in blood leading to inflammation. Can progress to shock if hypotension and organ dysfunction fail to respond to antimicrobial treatment
At what age are progenies of T cells established by?
Mid-twenties
Describe the thymus
Two lobes surrounded by connective tissue capsule. Short trabeculae project into outer portions of lobe subdividing them into lobules with an dark stained cortex around a pale medulla