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Blood and its components

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    Blood and its components Blood and its components Presentation Transcript

    • BLOOD ANATOMY
      BY DR. SUMAIYA TAREEN
    • BLOOD AND ITS COMPONENTS
    • Fluids of the Body
      Cells of the body are serviced by 2 fluids
      blood
      composed of plasma and a variety of cells
      transports nutrients and wastes
      interstitial fluid
      bathes the cells of the body
      Nutrients and oxygen diffuse from the blood into the interstitial fluid & then into the cells
      Wastes move in the reverse direction
      Hematology is study of blood and blood disorders
    • Physical Characteristics of Blood
      Thicker (more viscous) than water and flows more slowly than water
      Temperature of 100.4 degrees F
      pH 7.4 (7.35-7.45)
      8 % of total body weight
      Blood volume
      5 to 6 liters in average male
      4 to 5 liters in average female
      hormonal negative feedback systems maintain constant blood volume and osmotic pressure
    • Functions of Blood
      Transportation
      O2, CO2, metabolic wastes, nutrients, heat & hormones
      Regulation
      helps regulate pH through buffers
      helps regulate body temperature
      coolant properties of water
      vasodilatation of surface vessels dump heat
      helps regulate water content of cells by interactions with dissolved ions and proteins
      Protection from disease & loss of blood
    • Blood components
      55% plasma: 7 to 8% dissolved substances (sugars, amino acids, lipids & vitamins), ions, dissolved gases, hormones
      most of the proteins are plasma proteins: provide a role in balancing osmotic pressure and water flow between the blood and extracellular fluid/tissues
      loss of plasma proteins from blood – decreases osmotic pressure in blood and results in water flow out of blood into tissues – swelling
      most common plasma proteins: albumin, globulins, clotting proteins (fibrin)
    • Blood: Cellular elements
      45% of blood is the cellular elements or formed elements
      99% of this (44.55% of total blood) is erythrocytes or RBCs
      formed by differentiation of hematopoietic stem cells (HSCs) in the red bone marrow of long bones and pelvis – makes about 2 million per second!
      most numerous cell type in the body – 4 to 6 million per ul blood
      as they mature in the marrow they lose most organelles and its nucleus
      lack mitochondria and cannot use the oxygen they transport for ATP synthesis
      lives only about 120 days – destroyed by the liver and spleen
      liver degrades the hemoglobin to its globin component and the heme is degraded to a pigment called bilirubin - bile
      Iron(Fe+3)
      transported in blood attached to transferrin protein
      stored in liver, muscle or spleen
      attached to ferritin or hemosiderin protein
      in bone marrow being used for hemoglobin synthesis
    • 1% found in the Buffy coat :
      -leukocytes (WBCs) and platelets (thromobocytes)
      -neutrophils: phagocytic properties
      -release lysozymes which destroy/digest bacteria
      -release defensin proteins that act like antibiotics & poke holes in bacterial cell walls destroying them
      -release strong oxidants (bleach-like, strong chemicals ) that destroy bacteria
      - releases cytokines that attract other neutrophils
      -eosinophils: parasitic defense cells
      -also involved in the allergic response
      -release histaminase
      slows down inflammation caused by
      basophils
      -basophils: heparin, histamine & serotonin
      -heighten the inflammatory response and account for hypersensitivity (allergic) reaction
      -monocytes: enter various tissues and
      differentiate into phagocytic macrophages
      -lymphocytes: T and B cells
    • Blood Plasma
      • Composed of approximately 90 percent water
      • Includes many dissolved substances
      • Nutrients, Salts (metal ions)
      • Respiratory gases
      • Hormones
      • Proteins, Waste products
    • FORMED ELEMENTS OF BLOOD
      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)
    • Erythrocytes (Red Blood Cells)
      • The main function is to carry oxygen
      • Anatomy of circulating erythrocytes
      • Biconcave disks
      • Essentially bags of hemoglobin
      • Anucleate (no nucleus)
      • Contain very few organelles
      • Outnumber white blood cells 1000:1
    • Contain oxygen-carrying protein hemoglobin that gives blood its red color
      1/3 of cell’s weight is hemoglobin
      Biconcave disk 8 microns in diameter
      increased surface area/volume ratio
      flexible shape for narrow passages
      no nucleus or other organelles
      no cell division or mitochondrial ATP formation
      Normal RBC count
      male 5.4 million/drop ---- female 4.8 million/drop
      new RBCs enter circulation at 2 million/second
    • HAEMOGLOBIN
      • Iron-containing protein
      • Binds strongly, but reversibly, to oxygen
      • Each hemoglobin molecule has four oxygen binding sites
      • Each erythrocyte has 250 million hemoglobin molecules
      Globin protein consisting of 4 polypeptide chains
      One heme pigment attached to each polypeptide chain
      each heme contains an iron ion (Fe+2) that can combine reversibly with one oxygen molecule
    • Each hemoglobin molecule can carry 4 oxygen 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
      iron ions pick up nitric oxide (NO) & super nitric oxide (SNO)& transport it to & from the lungs
      NO causing vasoconstriction is released in the lungs
      SNO causing vasodilation is picked up in the lungs
    • Production of abnormal hemoglobin can result in serious blood disorders such as thalassemia and sickle cell anemia.
      The blood test, hemoglobin A1c, can be used to monitor blood glucose levels in diabetics
    • Hematocrit
      Percentage of blood occupied by cells
      female normal range
      38 - 46% (average of 42%)
      male normal range
      40 - 54% (average of 46%)
      testosterone
      Anemia
      not enough RBCs or not enough hemoglobin
      Polycythemia
      too many RBCs (over 65%)
      dehydration, tissue hypoxia, blood doping in athletes
    • Erythropoiesis: Production of RBCs
      Erythrocyte formation, called erythropoiesis, occurs in adult red bone marrow of certain bones.
      The main stimulus for erythropoiesis is hypoxia.
      Proerythroblast starts to produce hemoglobin
      Many steps later, nucleus is ejected & a reticulocyte is formed
      orange in color with traces of visible rough ER
      Reticulocytes escape from bone marrow into the blood
      In 1-2 days, they eject the remaining organelles to become a mature RBC
    • ANEMIA
      Symptoms
      oxygen-carrying capacity of blood is reduced
      fatigue, cold intolerance & paleness
      lack of O2 for ATP & heat production
      Types of anemia
      iron-deficiency = lack of absorption or loss of iron
      type of nutritional anemia
      failure to take in essential raw ingredients not made by the body
      pernicious = lack of intrinsic factor for vitamin B12 absorption from the digestive tract
      B12 is essential for normal RBC formation and maturation
      binding of B12 to intrinsic factor allows its absorption
      intrinsic factor – synthesized by the small intestine
    • hemorrhagic = loss of RBCs due to bleeding (ulcer)
      hemolytic = defects in cell membranes cause rupture
      rupture of too many RBCs by external factors such as malaria (normal RBCs) or genetic disorders like sickle cell anemia (defective RBCs)
      thalassemia= hereditary deficiency of hemoglobin
      aplastic = destruction of bone marrow (radiation/toxins)
      failure of the bone marrow to produce enough RBCs
      may selectively destroy the ability to produce RBCs only
      but may also destroy the myeloid stem cells – affect WBCs and platelets
    • WHITE BLOOD CELLS
      Leukocytes (white blood cells or WBCs) are nucleated cells and do not contain hemoglobin. Two principal types are granular (neutrophils, eosinophils, basophils) and agranular (lymphocytes and monocytes).
      Granular leukocytes include eosinophils, basophils, and neutrophils based on the straining of the granules.
      Agranular leukocytes do not have cytoplasmic granules and include the lymphocytes and monocytes, which differentiate into macrophages (fixed and wandering).
      Leukocytes have surface proteins, as do erythrocytes. They are called majorhistocompatibility antigens (MHC), are unique for each person (except for identical siblings), and can be used to identify a tissue.
    • Less numerous than RBCs
      5000 to 10,000 cells per drop of blood
      1 WBC for every 700 RBC
      Leukocytosis is a high white blood cell count
      microbes, strenuous exercise, anesthesia or surgery
      Leukopenia is low white blood cell count
      radiation, shock or chemotherapy
      Only 2% of total WBC population is in circulating blood at any given time
      rest is in lymphatic fluid, skin, lungs, lymph nodes & spleen
    • WBCs leave the blood stream by emigration.
      Some WBCs, particularly neutrophils and macrophages, are active in phagocytosis.
      The chemical attraction of WBCs to a disease or injury site is termed chemotaxis.
    • WBCs roll along endothelium, stick to it & squeeze between cells.
      adhesion molecules (selectins) help WBCs stick to endothelium
      displayed near site of injury
      molecules (integrins) found on neutrophils assist in movement through wall
      Neutrophils & macrophages phagocytize bacteria & debris
      chemotaxis of both
      kinins from injury site & toxins
    • Types of Leukocytes
      • Granulocytes
      • Granules in their cytoplasm can be stained
      • Include neutrophils, eosinophils, and basophils
      • Agranulocytes
      • Lack visible cytoplasmic granules
      • Include lymphocytes and monocytes
    • Granulocytes
      • Neutrophils
      • Multilobed nucleus with fine granules
      • Act as phagocytes at active sites of infection
      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 (bleach-like, strong chemicals ) that destroy bacteria
      • Eosinophils
      • Large brick-red cytoplasmic granules
      • Found in repsonse to allergies and parasitic worms
      Leave capillaries to enter tissue fluid
      Release histaminase
      slows down inflammation caused by basophils
      Attack parasitic worms
      Phagocytize antibody-antigen complexes
      • Basophils
      • Have histamine-containing granules
      • Initiate inflammation
      Involved in inflammatory and allergy reactions
      Leave capillaries & enter connective tissue as mast cells
      Release heparin, histamine & serotonin
      heighten the inflammatory response and account for hypersensitivity (allergic) reaction
    • Agranulocytes
      • Monocytes
      • Largest of the white blood cells
      • Function as macrophages
      • Important in fighting chronic infection
      Take longer to get to site of infection, but arrive in larger numbers
      Become wandering macrophages, once they leave the capillaries
      Destroy microbes and clean up dead tissue following an infection
      • Lymphocytes
      • Nucleus fills most of the cell
      • Play an important role in the immune response
      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
    • Platelets
      • Derived from ruptured multinucleate cells (megakaryocytes)
      • Needed for the clotting process
      • Normal platelet count = 300,000/mm3
    • Thrombopoietin stimulates myeloid stem cells to produce platelets.
      Myeloid stem cells develop into megakaryocyte-colony-forming cells that develop into megakaryoblasts.
      Megakaryoblasts transform into megakaryocyteswhich fragment.
      Each fragment, enclosed by a piece of cell membrane, is a platelet (thrombocyte).
      Normal blood contains 250,000 to 400,000 platelets/mm3. Platelets have a life span of only 5 to 9 days; aged and dead platelets are removed by fixed macrophages in the spleen and liver.
    • Disc-shaped, 2 - 4 micron cell fragment with no nucleus
      Normal platelet count is 150,000-400,000/drop of blood
      Other blood cell counts
      5 million red & 5-10,000 white blood cells
    • HEMOSTASIS
      A clot is a gel consisting of a network of insoluble protein fibers (fibrin) in which formed elements of blood are trapped.
      The chemicals involved in clotting are known as coagulation (clotting) factors; most are in blood plasma, some are released by platelets, and one is released from damaged tissue cells.
      Blood clotting involves a cascade of reactions that may be divided into three stages: formation of prothrombinase (prothrombin activator), conversion of prothrombin into thrombin, and conversion of soluble fibrinogen into insoluble fibrin.
    • Stoppage of bleeding in a quick & localized fashion when blood vessels are damaged
      Prevents hemorrhage (loss of a large amount of blood)
      Methods utilized
      vascular spasm
      platelet plug formation
      blood clotting (coagulation = formation of fibrin threads)
    • Platelet Plug Formation
      Platelets store a lot of chemicals in granules needed for platelet plug formation
      alpha granules
      clotting factors
      platelet-derived growth factor
      cause proliferation of vascular endothelial cells, smooth muscle & fibroblasts to repair damaged vessels
      dense granules
      ADP, ATP, Ca+2, serotonin, fibrin-stabilizing factor, & enzymes that produce thromboxane A2
      Steps in the process
      (1) platelet adhesion (2) platelet release reaction (3) platelet aggregation
    • Blood Clotting
      Blood drawn from the body thickens into a gel
      gel separates into liquid (serum) and a clot of insoluble fibers (fibrin) in which the cells are trapped
      If clotting occurs in an unbroken vessel is called a thrombosis
      Substances required for clotting are Ca+2, enzymes synthesized by liver cells and substances released by platelets or damaged tissues
      Clotting is a cascade of reactions in which each clotting factor activates the next in a fixed sequence resulting in the formation of fibrin threads
      prothrombinase & Ca+2 convert prothrombin into thrombin
      thrombin converts fibrinogen into fibrin threads
    • Prothrombinase is formed by either the intrinsic or extrinsic pathway
      Final common pathway produces fibrin threads
    • Extrinsic Pathway
      Damaged tissues leak tissue factor (thromboplastin) into bloodstream
      Prothrombinase forms in seconds
      In the presence of Ca+2, clotting factor X combines with V to form prothrombinase
    • Intrinsic Pathway
      Activation occurs
      endothelium is damaged & platelets come in contact with collagen of blood vessel wall
      platelets damaged & release phospholipids
      Requires several minutes for reaction to occur
      Substances involved: Ca+2 and clotting factors XII, X and V
    • Final Common Pathway
      Prothrombinase and Ca+2
      catalyze the conversion of prothrombin to thrombin
      Thrombin
      in the presence of Ca+2 converts soluble fibrinogen to insoluble fibrin threads
      activates fibrin stabilizing factor XIII
      positive feedback effects of thrombin
      accelerates formation of prothrombinase
      activates platelets to release phospholipids
    • Anticoagulants and Thrombolytic Agents
      Anticoagulants suppress or prevent blood clotting
      heparin
      administered during hemodialysis and surgery
      warfarin (Coumadin)
      antagonist to vitamin K so blocks synthesis of clotting factors
      slower than heparin
      stored blood in blood banks treated with citrate phosphate dextrose (CPD) that removes Ca+2
      Thrombolytic agents are injected to dissolve clots
      directly or indirectly activate plasminogen
      streptokinase or tissue plasminogen activator (t-PA)