علم الدمويات Hematology

dr.Hazemdr.Hazem مدير عام
Hematology is study of blood and blood disorders
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Cells of the body are serviced by 3 fluids


blood
composed of plasma and a variety of cells
transports nutrients, gases and wastes
interstitial fluid
bathes the cells of the body
Lymph
Interstitial fluid that does not directly return to blood vessels.
but first passes thru lymph nodes and then back to blood
Nutrients and oxygen diffuse from the blood into the interstitial fluid & then into the cells
Wastes and carbon dioxide move in the reverse direction

Composition of Blood

Blood is the body’s only fluid tissue
It is composed of liquid plasma and formed elements (Blood cells).
Formed elements include:
Erythrocytes, or red blood cells (RBCs)
Leukocytes, or white blood cells (WBCs)
Platelets
Hematocrit – the percentage of RBCs out of the total blood volume

Techniques of Blood Sampling


Venipuncture
sample taken from vein with
hypodermic needle & syringe
Why stick an vein?
less pressure
closer to the surface
Finger or heel stick
common technique for diabetics to monitor daily blood sugar
method used for infants

Physical Characteristics and Volume

Blood is a opaque fluid with a metallic taste
Color varies from red to dark red
Temperature is 38C, slightly higher than “normal” body temperature
Blood accounts for approximately 8% of body weight

Physical Characteristics

Thicker (more viscous) than water
Flows (Run)more slowly than water
pH 7.4 (7.35-7.45)
Blood volume
5 to 6 liters in average male
4 to 5 liters in average female
There is hormonal negative feedback systems witch maintain constant blood volume and osmotic pressure

التعليقات

  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/05/03
    Functions of Blood


    Transportation
    O2, CO2, metabolic wastes, nutrients, heat & hormones
    Regulation
    Regulate pH through buffers (As Phos +Bicar)
    Regulate body temperature
    High heat capacity and heat of vaporization for water
    vasodilatation of surface vessels allow heat to give out to environment. Vasoconstriction of surface vessels reduces head emission to environment.
    Regulate water content in cells by interactions with dissolved ions and proteins
    Protection from disease & loss of blood

    Components of Blood

    Hematocrit
    55% plasma
    45% cells
    99% RBCs
    < 1% WBCs and platelets

    Blood Plasma

    0ver 90% water
    7% plasma proteins
    created in liver
    limited to bloodstream
    Albumin
    maintain blood osmotic pressure
    Globulins (immunoglobulins)
    antibodies bind to foreignsubstances called antigens
    form antigen-antibody complexes
    Fibrinogen
    for clotting
    2% other substances
    electrolytes, nutrients, hormones, gases, waste products

    Functions of Blood :

    Blood transports

    Oxygen from the lungs and nutrients from the digestive tract
    Metabolic wastes from cells to the lungs and kidneys for elimination
    Hormones from endocrine glands to target organs

    Regulation

    Temperature by absorbing and distributing heat

    PH in body tissues using buffer systems

    Regulate water content in cells to gave adequate fluid volume in the circulatory system

    Protection
    Prevents from loss blood by:
    Activating plasma proteins and platelets
    Initiating the formation of clot when a vessel is broken
    Prevents from infection by:
    Synthesizing and utilizing antibodies
    Activating complement proteins
    Activating WBCs to defend the body against foreign invaders
  • دكتوربالفطرةدكتوربالفطرة عضو مميز
    تم تعديل 2010/05/04
    مشكور لجهودك معنا د.حازم الله لا يحرمنا همتك
  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/05/04
    تسلم أبو فرات ...
  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/05/04
    blood cells

    Erythrocytes, leukocytes, and platelets
    Only WBCs are complete cells
    RBCs have no nuclei or organelles, and platelets are just cell fragments
    Most blood cells survive in the bloodstream for only a few days
    Most blood cells do not divide but are renewed by cells in bone marrow
    Red blood cells ( erythrocytes )
    White blood cells ( leukocytes )
    granular leukocytes
    neutrophils
    eosinophils
    basophils
    agranular leukocytes
    lymphocytes = T cells, B cells, and natural killer cells
    monocytes
    Platelets (special cell fragments)


    Production of Leukocytes
    There are 2 families of cytokines:

    Interleukins (IL-1, IL-2)hematopoietic factors.
    CSFs colony-stimulating factors for the WBCs stimulates granulocytes.

    The important sources of cytokines are Macrophages and T cells.
    Clinically many hematopoietic hormones are used to stimulate bone marrow
    All leukocytes originate from Hemocytoblasts
    Hemocytoblasts differentiate into:
    Myeloid stem cells
    Lymphoid stem cells
    Myeloid stem cells become
    Myeloblasts, Monoblasts, Erythroblasts
    Lymphoid stem cells become lymphoblasts
    Lymphoblasts develop into lymphocytes.
    Myeloblasts develop into:Eosinophils, Neutrophils, and Basophils.
    Monoblasts develop into monocytes

    Agranulocytes Blood cells
    Lymphocytes and monocytes

    Lack visible cytoplasmic granules
    Similar structurally but:
    distinct functions.
    and distinct cell types
    Lymphocytes have spherical shape nuclei but the monocytes have kidney-shape nuclei.
    Monocytes account 4–8% of leukocytes
    Monocytes are the largest leukocytes
    They have abundant pale-blue cytoplasm's
    They have violet-staining nuclei.
    The nuclei have U- or kidney-shaped.
    Monocytes leave the circulation, enter tissue, and differentiate into macrophages
  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/05/06
    Monocyte Function
    In infection take longer time to get to site of infection, but arrive in larger numbers

    Become macrophages, once they leave the capillaries

    Destroy microbes.
    Clean up dead tissue following (after) an infection

    Macrophages Function
    Are highly mobile
    Dynamically phagocytic
    Activate lymphocytes to get bigger an immune response

    Lymphocyte Functions
    B cells
    Destroy bacteria and their toxins
    Turn into plasma cells that produces antibodies
    T cells
    Attack viruses, fungi, transplanted organs, cancer cells & some bacteria
    Natural killer cells
    Attack many different microbes & some tumor cells
    Destroy foreign invaders by direct attack

    Neutrophil Function
    Fastest response of all WBC to bacteria
    Direct actions against bacteria
    Release lysozymes which destroy/digest bacteria
    Release defensin proteins that act like antibiotics &
    Poke holes in bacterial cell walls destroying them
    Release strong oxidants (peroxide-like,strong
    chemicals) that destroy bacteria

    Eosinophil Function
    Leave capillaries to enter tissue fluid

    Release histaminase
    slows down inflammation caused by basophils

    Attack parasitic worms

    Phagocytize antibody-antigen complexes

    Basophil Function
    Involved in inflammatory and allergy reactions

    Leave capillaries enter connective tissue as mast cells

    Release heparin & histamine
    heighten the inflammatory response and account for hypersensitivity (allergic) reaction
  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/05/07
    Platelets

    Platelets are fragments of megakaryocytes with a blue-staining outer region and a lilac granular center
    Their granules contain serotonin, Ca2+, enzymes, ADP, and platelet-derived growth factor (PDGF)
    Platelets function in the clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels
    Platelets not involved in clotting are kept inactive by NO and prostaglandin I2
  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/05/09
    Production of Erythrocytes Erythropoiesis
    A hemocytoblast is transformed into proerythroblast
    Proerythroblasts develop into early erythroblasts
    The developmental pathway consists of three phases
    Phase 1 – ribosome synthesis in early erythroblasts
    Phase 2 – hemoglobin accumulation in late erythroblasts and normoblasts
    Phase 3 – ejection of the nucleus from normoblasts and formation of reticulocytes
    Reticulocytes then become mature erythrocytes
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    Regulation and Requirements for Erythropoiesis

    The number of erythrocytes remains constant and reflects a balance between RBC production and destruction
    Too few red blood cells leads to tissue hypoxia
    Too many red blood cells causes undesirable blood viscosity
    Erythropoiesis is hormonally controlled and depends on adequate supplies of iron, amino acids, and B vitamins

    Hormonal Control of Erythropoiesis

    Erythropoietin (EPO) release by the kidneys is triggered by:
    Hypoxia due to decreased RBCs
    Decreased oxygen availability
    Increased tissue demand for oxygen
    worse erythropoiesis decreases the:
    RBC count in circulating blood
    Oxygen carrying ability of the blood

    Erythrocytes (RBCs)

    Erythrocytes are an example of the complementarity's of structure and function
    Structural characteristics contribute to its gas transport function
    Biconcave shape that has a vast surface area relative to volume
    Discounting water content, erythrocytes are more than 97% hemoglobin
    ATP is generated an aerobically, so the erythrocytes do not consume the oxygen they transport
    Summary of Formed Elements

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  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/05/11
    Formation of Blood Cells


    Most blood cells types need to be continually replaced
    die within hours, days or weeks
    process of blood cells formation is hematopoiesis or hemopoiesis
    In the embryo
    occurs in yolk sac, liver, spleen, thymus, lymph nodes & red bone marrow
    In adult
    occurs only in red marrow of flat bones like sternum, ribs, skull & pelvis and proximal epiphysis of long bones
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    Stages of Blood Cell Formation

    Pluripotent stem cells
    0.1% of red marrow cells (can’t be distinguished from other cells)
    replenish themselves as they differentiate into either myeloid or lymphoid stem cells
    Myeloid stem cell line of development continues:
    progenitor cells(colony-forming units) no longer can divide and are specialized to form specific cell types
    example: CFU-E develops eventually into only red blood cells
    next generation is blast cells
    have recognizable histological characteristics
    develop within several divisions into mature cell types
    Lymphoid stem cell line of development
    pre-B cells & prothymocytes finish their develop into B & T lymphocytes in the lymphatic tissue after leaving the red marrow
  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/06/29
    Medical Uses of Growth Factors

    Available through recombinant DNA technology
    recombinant erythropoietin (EPO) very effective in treating decreased RBC production because of end-stage kidney disease as well as treating anemias
    other products given to stimulate WBC formation in cancer patients receiving chemotherapy which kills bone marrow
    granulocyte-macrophage colony-stimulating factor
    granulocyte colony stimulating factor
    thrombopoietin helps prevent platelet depletion during chemotherapy

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    Globin protein consisting of 4 polypeptide chains
    One heme pigment attached to each polypeptide chain
    each heme contains an iron ion (Fe2+) that can combine reversibly with one oxygen molecule

    Transport of O2, CO2 and Nitric Oxide

    Each hemoglobin molecule can carry 4 oxygens molecules from lungs to tissue cells

    Hemoglobin transports 23% of total CO2 waste from tissue cells to lungs for release
    combines with amino acids in globin portion of Hb

    Hemoglobin transports nitric oxide & super nitric oxide helping to regulate BP
  • dr.Hazemdr.Hazem مدير عام
    تم تعديل 2010/06/29
    RBC Life Cycle
    RBCs live only 120 days
    wear out from bending to fit through capillaries
    no repair possible due to lack of organelles
    Worn out cells removed by fixed/attached macrophages in spleen & liver
    Breakdown products are recycled
    Blood cells are replaced w/in 5-7 days after donation -uses up Fe3+ supplies
    Blood bank makes you wait 8 weeks
    Recycling of Hemoglobin Components
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    In macrophages of liver, spleen and/or red bone marrow
    globin portion broken down into amino acids & recycled
    heme portion split into iron (Fe3+) and biliverdin (green pigment)

    Erythropoiesis: Production of RBCs
    Requires Fe3+, vit B12, intrinsic factor, Erythropoetin, dietary protein
    Proerythroblast starts to produce hemoglobin
    Many steps later, nucleus is ejected & a reticulocyte is formed
    Reticulocytes escape from bone marrow into the blood
    In 1-2 days, they eject the remaining organelles to become a mature RBC

    Feedback Control of RBC Production

    Tissue hypoxia (cells not getting enough O2)
    high altitude since air has less O2
    Anemia: RBC production falls below RBC destruction
    circulatory problems
    Kidney response to hypoxia
    release erythropoietin
    speeds up development of proerythroblasts into reticulocytes
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    Normal Reticulocyte Count
    Should be 0.5 to 1.5% of the circulating RBC’s
    Low count indicate bone marrow problem
    Leukemia
    Nutritional deficiency.
    or failure of red bone marrow to respond to erythropoietin stimulation
    High count might indicate recent blood loss or successful iron therapy
  • الياسالياس عضو جديد
    تم تعديل 2011/03/11
    مشكور كتير دكتور حازم على هاد العمل الكبير و الرائع
  • المجهرالمجهر عضو جديد
    تم تعديل 2011/12/27
    [COLOR="rgb(0, 255, 255)"]شكراً جزيلاً علي المعلومات القيمة ،، وجعلها الله في ميزان حسناتك[/COLOR]