Introduction To Hematology


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Introduction To Hematology

  1. 1. Introduction to Hematology Annette Baker, MS, PA-C Objectives • At this end of this lecture the student will know: • The anatomy of blood • The function of plasma • The structure and function of erythrocytes, leukocytes, platelets and hemostasis Introduction • Represents about 8% of total body weight • Average volume of 5 liters in women • Average of 5.5 liters in men • Consists of three types of cellular elements • Erythrocytes, leukocytes and platelets • These are suspended in complex liquid called plasma
  2. 2. Introduction • 99% of cells are erythrocytes • Hematocrit or packed cell volume is defined as the percentage of total blood volume occupied by erythrocytes • Plasma accounts for the remaining volume • Hematocrit averages 42% for women and 45% for men Plasma • Functions of plasma are carried out by plasma proteins • Composed of 90% water • Plasma is able to absorb and distribute much of the heat generated metabolically within tissues • Most abundant electrolytes in the plasma are Na and Cl Plasma • Three groups of plasma proteins: • Albumin • Globulin • Fibrinogen
  3. 3. • These are classified according to various physical and chemical properties • Plasma proteins establish osmotic gradient between blood and interstitial fluid Plasma • Responsible for the plasma’s capacity to buffer changes in pH • Contribute to blood viscosity • Used as metabolic fuels in starvation states • Albumin the most abundant contribute most extensively to the colloid osmotic pressure • There are three subclasses of globulins: alpha, beta and gamma Plasma • Alpha and beta globulins bind and transport substances • Affects the process of blood clotting • Regulates the role of salt balance in the body • Gamma globulins are immunoglobulins that defends the body • Fibrinogen key factor in blood-clotting process
  4. 4. Erythrocytes • Primary function to transport oxygen transport in the blood • 5 billion erythrocytes clinically in a red blood cell count • Hemoglobin is transported by erythrocytes • Hemoglobin consists of two parts Erythrocytes • Hemoglobin combines with carbon dioxide to transport gas from tissue to lungs • Buffers acid so that it minimally alters the pH of the blood • Carbon monoxide Erythrocytes • Bone marrow replaces worn-out erythrocytes • Spleen destroys red blood cells • Erythropoiesis is the generation of new red blood cells
  5. 5. • Erythrocytes are generally produced by the yolk sac first Erythropoiesis • Erythropoietin is produced by the kidney • Immature red blood cells are called reticulocytes • Red bone marrow can be found in adults in the sternum, vertebrae, ribs, upper end of the long bones, and base of the skull Leukocytes • Also known as white blood cells • Mobile units of the body’s immune defense system • Function outside the blood • Leukocytes work by phagocytosis Leukocytes • Five different types of leukocytes • They lack hemoglobin; colorless unless stained
  6. 6. • Five types of circulating leukocytes are: neutrophils, eosinophils, basophils, monocytes, and lymphocytes Leukocytes • Polymorphonuclear granulocytes are the neutrophils, eosinophils and basophils • Monocytes and lymphocytes are known as mononuclear agranulocytes • Monocytes are larger of the two • Lymphocytes the smallest Leukocytes • Produced at varying rates depending on the changing defense needs of the body • Leukocytes originate from undifferentiated stem cells in the red bone marrow • Granulocytes and monocytes are produced only in the red bone marrow Hemopoiesis • All blood-cell types ultimately originate from the same undifferentiated pluripotent stem cells • Bone marrow produces all circulating blood cells except lymphocytes
  7. 7. • These are produced by lymphoid tissue Leukocytes • Neutrophils accompanies bacteria infection • Eosinophils associated with allergic conditions and internal parasite infestations • Basophils dispersed in the connective tissue • Basophils secrete histamine and heparin • Monocytes are phagocytes Lymphocytes • Provide immune defense against targets • Two types of lymphocytes • B and T
  8. 8. • B lymphocytes produce antibodies • T lymphocytes destroy cell-mediated immune response Platelets • Bone-marrow-bound cells known as megakaryocytes • Derived from undifferentiated stem cells Complete Blood Count • Also known as CBC • Provides detailed information about three types of cells in the blood: red blood cells, white blood cells and platelets • Blood cells made from bone marrow • Measures white blood cell count, red blood cell count, hemoglobin, hematocrit and platelet count CBC • WBC (White Blood Cell) count measured in thousands per cubic milliliter (K/mm3) of blood • Normal range: 3.4-9.6 K/mm3 • RBC measured in millions/cubic millimeter (mil/mm3) of blood
  9. 9. • RBC: 4.5-6.0 mil/mm3 males; 4.0-5.5 mil/mm3 in female CBC • Hemoglobin measured in grams per deciliter (g/dl) of blood • Hgb range is 13.5-17.5 g/dl for males • Hgb range is 12.5-15.5 g/dl for females • Hematocrit is the percentage of red blood cells in relation to your total blood volume • HCT 41%-52% male and 36%-48% female Indices • MCV: average red cell volumes • Measured in fl • Value 80-100 fl • MCH: average red cell hemoglobin concentration • Measured in picograms • Values: 27-32 pg Indices
  10. 10. • MCHC: compares the weight of hemoglobin in a red cell to the size of the cell • Reported in percentage or g/dl • Values: 33-38 percent CBC • Leukopenia- decrease in number of leukocytes in blood • Leukocytosis – increase in number of leukocytes in blood • Neutropenia- decrease neutrophil count • Neutrocytosis- increase neutrophil count CBC • Anisocytosis: markedly different sizes of red cell • Poikilocytosis: significantly variation in shape of the erythrocytes • Macrocytosis increase in size of cell • Microcytosis decrease in size of cell • Helmet cell membrane injured cells found in certain conditions CBC
  11. 11. • Spherocytosis: dense stained red cells lacking in central pallor • Diameter less than normal sized red cells • Target cells: have central are of hemoglobin pigment surrounded by relatively clear are and peripheral rim of hemoglobin to center of cell