Hematopoiesis

Total Page:16

File Type:pdf, Size:1020Kb

Hematopoiesis See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/300889403 Hematopoiesis Chapter · December 2015 DOI: 10.1016/B978-0-12-801238-3.05054-6 CITATIONS READS 0 13,987 2 authors, including: Yusuke Shiozawa Wake Forest School of Medicine 109 PUBLICATIONS 3,898 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Open for Submission-Special Issue "Targeting Bone Metastasis in Cancer" View project Bone metastasis View project All content following this page was uploaded by Yusuke Shiozawa on 30 May 2018. The user has requested enhancement of the downloaded file. Hematopoiesis☆ R Kawahara, University of Nebraska Medical Center, Omaha, NE, USA Y Shiozawa, University of Michigan School of Dentistry, Ann Arbor, MI, USA. ã 2015 Elsevier Inc. All rights reserved. Introduction 1 Methods to Study Hematopoiesis 2 Hematopoietic Stem Cell Markers 2 Hematopoiesis During Development 2 Hematopoietic Stem Cell Niche 3 Hematopoietic Stem Cell Plasticity 3 References 4 Introduction Hematopoiesis is the process by which the entire repertoire of blood cell lineages is generated from hematopoietic stem cells (Figure 1). The term hematopoiesis is all-encompassing and includes erythropoiesis, leukopoiesis, and thrombopoiesis, all of which are involved in the production of erythrocytes (red blood cells). In addition, leukopoiesis includes lymphopoiesis, which relates to the generation of lymphocytes and granulocyte-macrophage lineages of myelopoiesis (myelos is Greek for marrow). Adult blood cells types can be separated by sedimentation or by centrifugation of blood samples. On examination of the sample, a red cell layer that is composed of hemoglobin-containing erythrocytes (erthrosis Greek for red) comprises 45% of the total blood volume. Erythrocytes facilitate the transport of oxygen and carbon dioxide between the lungs and tissues. On top of the red cell layer is a thin, white, buffy coat that contains white blood cells or leukocytes (leukos is Greek for white). Leukocytes, which occupy 1% of the blood volume, are composed of granulocytes (leukocytes with granules), monocytes, and lymphocytes. Different types of granulocytes are distinguished using acidic or basic dyes. Whereas eosinophils stain readily with eosin, an acidic dye, basophils stain readily with basic dyes, and neutrophils lack affinity for either acidic or basic dyes. Sixty percent of the leukocytes are neutrophils. Together, leukocytes function as components of the immune system. Examination of a blood clot reveals aggregates of thrombocytes or platelets. Platelets, like adult erythrocytes, do not have a nucleus. Their function is to adhere and aggregate at the site of an injury to form the primary hemostatic plug to prevent further blood loss. Figure 1 Major differentiation pathways of hematopoiesis. Mature blood cells differentiate from pluripotent hematopoietic stem cells. The differentiation of mature blood cells from hematopoietic stem cells represents a continuous process that involves discrete changes triggered by the surrounding microenvironment and cumulative signals from soluble glycoprotein factors. The signals that stimulate mature blood cell production and signals that act to prevent the overproduction of blood cells are carefully balanced to supply the quantity of blood cells necessary for life. Not all of the regulatory processes are fully understood. Early progenitor cells, such as the colony-forming-unit granulocyte, erythrocyte, macrophage, megakaryocyte (CFU-GEMM), are able to differentiate into multiple lineages but are unable to reconstitute the entire hematopoietic system when transplanted into an irradiated host. ☆ Change History: December 2014. Y Shiozawa made small edits in the text, added Keywords, Abstract, ‘Hematopoietic stem cell markers’ section, ‘Hematopoietic stem cell niche’ section, three references. Reference Module in Biomedical Research http://dx.doi.org/10.1016/B978-0-12-801238-3.05054-6 1 2 Hematopoiesis Methods to Study Hematopoiesis Microscopic examination after staining with dyes is an important procedure for studying fully differentiated blood cells and their immediate precursors. Differentiated blood cells and precursors have a defined morphological appearance and can be distin- guished readily from each other by direct observation. Precursor cells have limited proliferation potential and differentiate into mature blood cells with finite life spans. The progenitor cell compartment is composed of cells committed to develop into one or more blood lineages. Multilineage progenitor cells are presumed to be more primitive than progenitor cells committed to a single lineage. Cells in this compartment display greater plasticity and proliferative potential as compared to the precursor cell compartment. Progenitor cells are not morphologically distinguishable by microscopic examination. Surface markers and functional assays are used to distinguish progenitor cells from each other. To examine cell-surface markers, multiple monoclonal antibodies that recognize a common cell-surface antigen are joined together to form clusters of differentiation (CD). The clusters are numbered sequentially with respect to when they were discovered and defined. The cell-surface reactivity of monoclonal antibodies to each CD antigen is detected by flow cytometry. The presence and abundance of cell-surface antigens are a distinguishing characteristic of the different progenitor populations and other cells that comprise the hematopoietic system. Selected CD antigens are used as lineage-specific markers. Common cell-surface markers include CD34 for stem cells, Mac-1 for macrophages, Gr-1 for granulocytes, ter-119 for reticulocytes, À CD3 and CD8 for T-cells, and B220 for B-lymphocytes. Stem cells are lineage marker negative (Lin ) because they do not express surface markers used to identify mature blood cells. The colony-forming assay is an in vitro functional assay used to define the process of hematopoiesis. Cells to be tested are harvested and resuspended in methylcellulose or agarose with culture media and growth factors. Over the next few days, responding cells proliferate and differentiate to form discrete colonies. Larger colonies contain highly proliferative cells with multilineage potential. Smaller colonies with lower proliferative potential give rise to mature blood cells within a shorter period of time. Highly proliferative progenitors are also detected in blast-forming assays, a variant of the colony-forming assay. In the blast- forming assay, primary colonies are replated and analyzed for their ability to form secondary colonies. A colony-forming assay capable of definitively identifying hematopoietic stem cells has yet to be developed. The standard for the presence of hematopoietic stem cells is the ability of the cells to regenerate the entire hematopoietic system when transplanted into an irradiated host. Hematopoietic stem cells, which can be concentrated by selecting for cells that express the CD34 cell-surface antigen, are rare cells that can self-renew and differentiate into highly proliferative progenitor cells of all blood lineages. A second side population of CD34 negative hematopoietic stem cells has been identified that may represent an earlier stage in stem cell maturation Goodell et al (1997). In addition to hematopoietic stem cells, the bone marrow contains mesenchymal stem cells that are able to differentiate into bone, muscle, cartilage, and fat, but not blood cells. Hematopoietic Stem Cell Markers Since hematopoietic stem cells are an extremely rare population in the marrow (approximately 1/10000 bone marrow cells), the identification of hematopoietic stem cells in the marrow is still challenging. Historically, the functional assays, including in vitro colony-forming assay and in vivo serial dilution transplantation assay, are used to determine stem cell activity. It has been recently shown that the combination of several cell-surface markers can be used to identify hematopoietic stem cells. For human stem cells, CD34+CD38-CD90+CD45R-Lin- cells (Stem cell frequency 1/10 cells) are defined as hematopoietic stem cells Majeti et al, 2007. For mouse, CD150+CD244-CD48-Sca-1+c-Kit+Lin- cells (Stem cell frequency 1/2 cells) are used to identify hematopoi- etic stem cells Kiel et al, 2005. Hematopoiesis During Development The early stages of mammalian hematopoiesis, which begins in the blood islands of the yolk sac, may be divided into two developmental processes (Figure 2). In mice, primitive hematopoiesis begins at embryonic day 7 and is sustained for a relatively short period of time. A common precursor, the hemangioblast, gives rise to both endothelial cells and the primitive hematopoietic cells of the early circulatory system. Primitive hematopoiesis is characterized by the production of large nucleated erythrocytes that express embryonic globins. There are a several primitive monocytes/macrophages and megakaryocytes that are also produced. The switch from primitive hematopoiesis to definitive hematopoiesis coincides with the switch of the principal site of hematopoiesis from the yolk sac to the fetal liver. This switch occurs between embryonic days 10 and 11 in the mouse. Definitive hematopoiesis is distinguished from primitive hematopoiesis by the presence of enucleated adult-type erythrocytes that produce fetal globin in humans and adult globin in the mouse. Long-term repopulating stem cells (LTRSC) capable of reconstituting the
Recommended publications
  • Inflammation 14.11. 2004
    Inflammation • Inflammation is the response of living tissue to damage. The acute inflammatory response has 3 main functions. Inflammation • The affected area is occupied by a transient material called the acute inflammatory exudate . The exudate carries proteins, fluid and cells from local blood vessels into the damaged area to mediate local defenses. • If an infective causitive agent (e.g. bacteria) is present in the damaged area, it can be destroyed and eliminated by components of the exudate . 14.11. 2004 • The damaged tissue can be broken down and partialy liquefied, and the debris removed from the site of damage. Etiology Inflammation • The cause of acute inflammation may • In all these situations, the inflammatory be due to physical damage, chemical stimulus will be met by a series of changes in substances, micro-organisms or other the human body; it will induce production of agents. The inflammatory response certain cytokines and hormones which in turn consist of changes in blood flow, will regulate haematopoiesis, protein increased permeability of blood vessels and escape of cells from the synthesis and metabolism. blood into the tissues. The changes • Most inflammatory stimuli are controlled by a are essentially the same whatever the normal immune system. The human immune cause and wherever the site. system is divided into two parts which • Acute inflammation is short-lasting, constantly and closely collaborate - the innate lasting only a few days. and the adaptive immune system. Inflammation Syst emic manifesta tion • The innate system reacts promptly without specificity and memory. Phagocytic cells are important contributors in innate of inflammation reactivity together with enzymes, complement activation and acute phase proteins.
    [Show full text]
  • WHITE BLOOD CELLS Formation Function ~ TEST YOURSELF
    Chapter 9 Blood, Lymph, and Immunity 231 WHITE BLOOD CELLS All white blood cells develop in the bone marrow except Any nucleated cell normally found in blood is a white blood for some lymphocytes (they start out in bone marrow but cell. White blood cells are also known as WBCs or leukocytes. develop elsewhere). At the beginning of leukopoiesis all the When white blood cells accumulate in one place, they grossly immature white blood cells look alike even though they're appear white or cream-colored. For example, pus is an accu- already committed to a specific cell line. It's not until the mulation of white blood cells. Mature white blood cells are cells start developing some of their unique characteristics larger than mature red blood cells. that we can tell them apart. There are five types of white blood cells. They are neu- Function trophils, eosinophils, basophils, monocytes and lymphocytes (Table 9-2). The function of all white blood cells is to provide a defense White blood cells can be classified in three different ways: for the body against foreign invaders. Each type of white 1. Type of defense function blood cell has its own unique role in this defense. If all the • Phagocytosis: neutrophils, eosinophils, basophils, mono- white blood cells are functioning properly, an animal has a cytes good chance of remaining healthy. Individual white blood • Antibody production and cellular immunity: lympho- cell functions will be discussed with each cell type (see cytes Table 9-2). 2. Shape of nucleus In providing defense against foreign invaders, the white • Polymorphonuclear (multilobed, segmented nucleus): blood cells do their jobs primarily out in the tissues.
    [Show full text]
  • Cell Dose on Engraftment After Scts: Personalized Estimates Based on Mathematical Modeling
    Bone Marrow Transplantation (2014) 49, 30–37 & 2014 Macmillan Publishers Limited All rights reserved 0268-3369/14 www.nature.com/bmt ORIGINAL ARTICLE The impact of CD34 þ cell dose on engraftment after SCTs: personalized estimates based on mathematical modeling T Stiehl1,ADHo2 and A Marciniak-Czochra1,3 It is known that the number of transplanted cells has a significant impact on the outcome after SCT. We identify issues that cannot be addressed by conventional analysis of clinical trials and ask whether it is possible to develop a refined analysis to conclude about the outcome of individual patients given clinical trial results. To accomplish this, we propose an interdisciplinary approach based on mathematical modeling. We devise and calibrate a mathematical model of short-term reconstitution and simulate treatment of large patient groups with random interindividual variation. Relating model simulations to clinical data allows quantifying the effect of transplant size on reconstitution time in the terms of patient populations and individual patients. The model confirms the existence of lower bounds on cell dose necessary for secure and efficient reconstitution but suggests that for some patient subpopulations higher thresholds might be appropriate. Simulations demonstrate that relative time gain because of increased cell dose is an ‘interpersonally stable’ parameter, in other words that slowly engrafting patients profit more from transplant enlargements than average cases. We propose a simple mathematical formula to approximate the effect of changes of transplant size on reconstitution time. Bone Marrow Transplantation (2014) 49, 30–37; doi:10.1038/bmt.2013.138; published online 23 September 2013 Keywords: SCT; hematopoiesis; mathematical modeling INTRODUCTION of benefit to individuals.
    [Show full text]
  • White Blood Cells)
    Lec.4 Medical Physiology – Blood Physiology Z.H.Kamil Leukocytes (White Blood Cells) Leukocytes are the only formed elements that are complete cells, with nuclei and the usual organelles. Accounting for less than 1% of total blood volume, leukocytes are far less numerous than red blood cells. On average, there are 4800–10,800 WBCs/μl of blood. Leukocytes are crucial to our defense against disease. They form a mobile army that helps protect the body from damage by bacteria, viruses, parasites, toxins, and tumor cells. As such, they have special functional characteristics. Red blood cells are kept into the bloodstream, and they carry out their functions in the blood. But white blood cells are able to slip out of the capillary blood vessels in a process called diapedesis and the circulatory system is simply their means of transport to areas of the body (mostly loose connective tissues or lymphoid tissues) where they mount inflammatory or immune responses. The signals that prompt WBCs to leave the bloodstream at specific locations are cell adhesion molecules displayed by endothelial cells forming the capillary walls at sites of inflammation. Once out of the bloodstream, leukocytes move through the tissue spaces by amoeboid motion (they form flowing cytoplasmic extensions that move them along). By following the chemical trail of molecules released by damaged cells or other leukocytes, a phenomenon called positive chemotaxis, they pinpoint areas of tissue damage and infection and gather there in large numbers to destroy foreign substances and dead cells. Whenever white blood cells are mobilized for action, the body speeds up their production and their numbers may double within a few hours.
    [Show full text]
  • Significance of Peroxidase in Eosinophils Margaret A
    University of Colorado, Boulder CU Scholar Series in Biology Ecology & Evolutionary Biology Spring 4-1-1958 Significance of peroxidase in eosinophils Margaret A. Kelsall Follow this and additional works at: http://scholar.colorado.edu/sbio Recommended Citation Kelsall, Margaret A., "Significance of peroxidase in eosinophils" (1958). Series in Biology. 14. http://scholar.colorado.edu/sbio/14 This Article is brought to you for free and open access by Ecology & Evolutionary Biology at CU Scholar. It has been accepted for inclusion in Series in Biology by an authorized administrator of CU Scholar. For more information, please contact [email protected]. SIGNIFICANCE OF PEROXIDASE IN EOSINOPHILS M a rg a ret A . K e lsa ll Peroxidase-bearing granules are the primary component and product of eosino­ phils. The physiological significance of eosinophils is, therefore, considered to be related to the ability of this cell to synthesize, store, and transport peroxidase and to release the peroxidase-positive granules into body fluids by a lytic process that is controlled by hormones, by variations in the histamine-epinephrine balance, and by several other stimuli. Peroxidase occurs not only in eosinophils, but also in neutrophils and blood platelets; but it is not present in most cells of animal tissues. The purpose of this work is to consider, as a working hypothesis, that the function of eosinophils is to produce, store, and transport peroxidase to catalyze oxidations. Many of the aerobic dehydrogenases that catalyze reactions in which hydrogen peroxide is produced are involved in protein catabolism. Therefore, relations between eosinophils and several normal and pathological conditions of increased protein catabolism are emphasized, and also the significance of peroxi­ dase in eosinophils and other leukocytes to H 20 2 produced by irradiation is considered.
    [Show full text]
  • Blood Dyscrasias
    MEDICATION-INDUCED BLOOD DYSCRASIAS Etiology And Disease Types Jassin M. Jouria, MD Dr. Jassin M. Jouria is a medical doctor, professor of academic medicine, and medical author. He graduated from Ross University School of Medicine and has completed his clinical clerkship training in various teaching hospitals throughout New York, including King’s County Hospital Center and Brookdale Medical Center, among others. Dr. Jouria has passed all USMLE medical board exams, and has served as a test prep tutor and instructor for Kaplan. He has developed several medical courses and curricula for a variety of educational institutions. Dr. Jouria has also served on multiple levels in the academic field including faculty member and Department Chair. Dr. Jouria continues to serves as a Subject Matter Expert for several continuing education organizations covering multiple basic medical sciences. He has also developed several continuing medical education courses covering various topics in clinical medicine. Recently, Dr. Jouria has been contracted by the University of Miami/Jackson Memorial Hospital’s Department of Surgery to develop an e-module training series for trauma patient management. Dr. Jouria is currently authoring an academic textbook on Human Anatomy & Physiology. Abstract Although drug-induced hematologic disorders are less common than other types of adverse reactions, they are associated with significant morbidity and mortality. Some agents, such as hemolytics, cause predictable hematologic disease, but others induce idiosyncratic reactions not directly related to the drug’s pharmacology. The most important part of managing hematologic disorders is the prompt recognition that a problem exists. The main mechanisms to manage hematologic disorders include vigilance to observe signs and symptoms indicating a blood disorder and patient education of the warning symptoms to alert them of the need to report a condition to their primary care provider or an emergency health team.
    [Show full text]
  • The Tel-Pdgfrß Fusion Gene Produces a Chronic
    Leukemia (1999) 13, 1790–1803 1999 Stockton Press All rights reserved 0887-6924/99 $15.00 http://www.stockton-press.co.uk/leu The Tel-PDGFR␤ fusion gene produces a chronic myeloproliferative syndrome in transgenic mice KA Ritchie1,2 AAG Aprikyan1,3, DF Bowen-Pope2, CJ Norby-Slycord1,2, S Conyers1, E Sitnicka4,5 SH Bartelmez4,5 and DD Hickstein1,3 1Medical Research Service, VA Puget Sound Health Care System, Seattle, WA; 5Seattle Biomedical Research Institute Seattle, WA; Department of 4Pathobiology School of Public Health, and Departments of 2Pathology, and 3Medicine, School of Medicine, University of Washingon, Seattle, WA, USA Chronic myelomonocytic leukemia (CMML) is a pre-leukemic with myeloid metaplasia (MMM), and granulocytes in chronic syndrome that displays both myelodysplastic and myeloprolif- myeloid leukemia (CML). All the MPS are characterized by erative features. The t(5;12) chromosomal translocation, present in a subset of CMML patients with myeloproliferation splenomegaly, and may display subacute clinical problems fuses the amino terminal portion of the ets family member, Tel, associated with the hyperplastic lineage (eg hyperviscosity in with the transmembrane and tyrosine kinase domains of plate- PV, thrombosis in ET). Over time, these diseases may evolve let-derived growth factor receptor ␤ (PDGFR␤) gene. To investi- into marrow failure. All of the MPS are associated with an gate the role of this fusion protein in the pathogenesis of increased risk of developing leukemia, best exemplified by ␤ CMML, we expressed the Tel-PDGFR fusion cDNA in hemato- CML, which progresses from a chronic phase to an acute poietic cells of transgenic mice under the control of the human CD11a promoter.
    [Show full text]
  • Immature/Transitional 1 B Cells Recombination, and Antibody
    T-Independent Activation-Induced Cytidine Deaminase Expression, Class-Switch Recombination, and Antibody Production by Immature/Transitional 1 B Cells This information is current as of September 26, 2021. Yoshihiro Ueda, Dongmei Liao, Kaiyong Yang, Anjali Patel and Garnett Kelsoe J Immunol 2007; 178:3593-3601; ; doi: 10.4049/jimmunol.178.6.3593 http://www.jimmunol.org/content/178/6/3593 Downloaded from References This article cites 38 articles, 19 of which you can access for free at: http://www.jimmunol.org/content/178/6/3593.full#ref-list-1 http://www.jimmunol.org/ Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication by guest on September 26, 2021 *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2007 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology T-Independent Activation-Induced Cytidine Deaminase Expression, Class-Switch Recombination, and Antibody Production by Immature/Transitional 1 B Cells1 Yoshihiro Ueda, Dongmei Liao, Kaiyong Yang, Anjali Patel, and Garnett Kelsoe2 Inflammation elicits a splenic lymphopoiesis of unknown physiologic significance but one that juxtaposes developing B cells and exogenous Ag.
    [Show full text]
  • IL-4 Determines Eicosanoid Formation in Dendritic Cells by Down-Regulation of 5-Lipoxygenase and Up-Regulation of 15-Lipoxygenase 1 Expression
    IL-4 determines eicosanoid formation in dendritic cells by down-regulation of 5-lipoxygenase and up-regulation of 15-lipoxygenase 1 expression Rainer Spanbroek*†, Markus Hildner*, Andre´ Ko¨ hler‡, Angelika Mu¨ ller‡, Felix Zintl‡, Hartmut Ku¨ hn§, Olof Rådmark¶, Bengt Samuelsson¶, and Andreas J. R. Habenicht* *Center for Vascular Medicine, Friedrich Schiller University Jena, Nordha¨userstrasse 78, 99089 Erfurt, Germany; ‡Children’s Hospital, Kochstrasse 2, 07740 Jena, Germany; §Institute of Biochemistry, Humboldt University Berlin, Hessische Strasse 3-4, 10115 Berlin, Germany; and ¶Department of Medical Biochemistry and Biophysics, Division of Chemistry II, Karolinska Institutet, S-17177 Stockholm, Sweden Contributed by Bengt Samuelsson, February 15, 2001 Dendritic cell (DC) differentiation from human CD34؉ hematopoi- transcripts of LT receptors are expressed in lymphoid organs etic progenitor cells (HPCs) can be triggered in vitro by a combi- (unpublished data); 5-LO-deficient mice show reduced ovalbu- nation of cytokines consisting of stem cell factor, granulocyte- min-dependent cellular and humoral immune responses during macrophage colony-stimulating factor, and tumor necrosis factor antigen-dependent allergenization of the lung (7); and mice ␣. The immune response regulatory cytokines, IL-4 and IL-13, deficient in the cysteinyl LT transporter multidrug resistance promote DC maturation from HPCs, induce monocyte-DC transdif- protein-1 have a defect in DC mobilization from skin to lymph ferentiation, and selectively up-regulate 15-lipoxygenase 1 (15- nodes (8). Although these data associate the 5-LO pathway with LO-1) in blood monocytes. To gain more insight into cytokine- the adaptive immune response, the precise molecular mecha- regulated eicosanoid production in DCs we studied the effects of nisms of LTs action within the immune system remain elusive.
    [Show full text]
  • Pre and Postnatal Hematopoiesis
    Pre_ and postnatal hematopoiesis Assoc. Prof. Sinan Özkavukcu Department of Histology and Embryology Lab Director, Center for Assisted Reproduction, Dep. of Obstetrics and Gynecology [email protected] 3 8 6 40 8 28 18 E Hemopoiesis (Hematopoiesis) • It is carried out in hematopoietic organs. • Erythropoiesis • Leukopoiesis • Thrombopoiesis ■Erythrocytes, platelets and granulocytes (neutrophils, eosinophils, basophil leukocytes) of blood cells are produced in myeloreticular tissue (red bone marrow). ■Agranulocytes (lymphocytes and monocytes); they are made both in the red bone marrow and in the lymphoreticular tissues (lymphoid organs). Ensuring continuity • The circulating blood cells have certain lifetimes. The cells are constantly destroyed and renewed. Therefore, a continuous production dynamics is needed. Blood product Life span Red blood cells 120 days Fetal red blood cells 90 days Platelets 7-12 days Transfused platelets 36 hours 8-12 hours in circulation Neutrophils 4-5 days in tissue Prenatal hematopoiesis • Yolk sac Stage 3rd Week Hemangioblast formation Prenatal Hemopoez Mesoblastic phase (2nd week-mesoderm of the yolk sac) Hepatosplenothymic phase Liver (6th week) Spleen (8th week) Thymus (8th week) Medullalymphatic phase (3-5th month) Temporary blood islets of the yolk sac • In the 3rd week of embryological development, mesodermal cells in the yolk sac wall are differentiated into hemangioblast cells. • These cells are the precursors of both blood cells and endothelial cells that will form the vascular system. • Blood precursors formed in this region are temporary. • The main hematopoietic stem cells develop from the mesoderm surrounding the aorta, called the aorta-gonad-mesonephros region (AGM), next to the developing mesonephric kidney. • These cells colonize the liver and form the main fetal hematopoietic organ (2-7th month of pregnancy) • Cells in the liver then settle into the bone marrow, and from the 7th month of pregnancy, the bone marrow becomes the final production center 1.
    [Show full text]
  • Chapter 21 the Lymphatic System
    Chapter 21 Lecture Outline See separate PowerPoint slides for all figures and tables pre- inserted into PowerPoint without notes. Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 Introduction • The body harbors at least 10 times as many bacterial cells as human cells – Some beneficial – Some potentially disease-causing • Immune system—not an organ system, but a cell population that inhabits all organs and defends the body from agents of disease – Especially concentrated in the true organ system: lymphatic system • Network of organs and vein-like vessels that recover fluid • Inspect it for disease agents • Activate immune responses • Return fluid to the bloodstream 21-2 The Lymphatic System • Expected Learning Outcomes – List the functions of the lymphatic system. – Explain how lymph forms and returns to the bloodstream. – Name the major cells of the lymphatic system and state their functions. – Name and describe the types of lymphatic tissue. – Describe the structure and function of the red bone marrow, thymus, lymph nodes, tonsils, and spleen. 21-3 The Lymphatic System • Fluid recovery – Fluid continually filters from the blood capillaries into the tissue spaces • Blood capillaries reabsorb 85% • 15% (2 to 4 L/day) of the water and about half of the plasma proteins enter the lymphatic system and then are returned to the blood 21-4 The Lymphatic System • Immunity – Excess filtered fluid picks up foreign cells and chemicals from the tissues • Passes through lymph nodes where immune cells stand guard against foreign matter • Activates a protective immune response • Lipid absorption – Lacteals in small intestine absorb dietary lipids that are not absorbed by the blood capillaries 21-5 The Lymphatic System Copyright © The McGraw-Hill Companies, Inc.
    [Show full text]
  • Studies of Neutrophil Production and Turnover in Grey Collie Dogs with Cyclic Neutropenia
    Studies of neutrophil production and turnover in grey collie dogs with cyclic neutropenia D. C. Dale, … , H. R. Kimball, S. M. Wolff J Clin Invest. 1972;51(8):2190-2196. https://doi.org/10.1172/JCI107026. Research Article 12 grey collie dogs had cyclic neutropenia with the neutropenia recurring at 11.8±0.1-day intervals. The recovery from neutropenia was accompanied by a single wave of myeloid proliferation, an increase in marrow myeloid-labeling indices, and an increase in serum muramidase levels. After recovery from neutropenia during the period when blood neutrophils (PMN) were normal or increased, marrow myeloid precursors became scarce. The decline in marrow precursors and marrow PMN reserves heralded the recurrence of neutropenia. Neither diisopropyl fluorophosphate (DF32P) leukokinetic studies nor the rate of development of neutropenia suggested shortened PMN survival as a mechanism for the neutropenia. These studies indicate that the cyclic neutropenia is due to a regularly recurring failure in PMN production. Find the latest version: https://jci.me/107026/pdf Studies of Neutrophil Production and Turnover in Grey Collie Dogs with Cyclic Neutropenia D. C. DALE, S. B. WARD, H. R. KIMBALL, and S. M. WOLFF From the Department of Health, Education and Welfare, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Laboratory of Clinical Investigation, Bethesda, Maryland 20014 A B S T R A C T 12 grey collie dogs had cyclic neutropenia -METHODS with the neutropenia recurring at 11.8+0.1-day intervals. Dogs. 12 grey collie dogs of both sexes were acquired The recovery from neutropenia was accompanied by a from eight breeders in six states.
    [Show full text]