Transcript Document
BLOOD: FUNCTION • Transport ▫ O2 • Protection ▫ CO2 ▫ Platelets and clotting factors ▫ Nutrients ▫ Inflammation ▫ Wastes ▫ Antibodies ▫ Hormones ▫ Leukocytes ▫ Ions ▫ Proteins Regulation Stabilizes pH Water balance of tissues Body temperature PHYSICAL CHARACTERISTICS • Color ▫ Bright red when oxygenated • pH ▫ 7.35 to 7.45 • Volume ▫ 4-5 liters in females ▫ 5-6 liters in males • Viscosity ▫ 5 times as viscous as water BLOOD: COMPONENTS • Hematocrit Plasma •55% of whole blood Buffy coat •Leukocytes & platelets •<1% of whole blood Erythrocytes •45% of whole blood BLOOD: COMPONENTS • Plasma ▫ Clear fluid matrix • Erythrocytes ▫ Red blood cells • Leukocytes ▫ White blood cells • Thrombocytes ▫ Platelets Plasma •55% of whole blood Buffy coat •Leukocytes & platelets •<1% of whole blood Erythrocytes •45% of whole blood COMPOSITION OF PLASMA • 92% water • Proteins (8%) ▫ Albumins ▫ Globulins ▫ Clotting proteins • Nutrients ▫ Glucose ▫ Amino acids ▫ Lipids • Wastes ▫ Urea (amino acid breakdown) • Electrolytes ▫ Na+, K+, Ca2+, Cl-, HCO3- • Gases • Hormones • SERUM = plasma without the clotting proteins PLASMA PROTEINS • Albumins ▫ 60 % of blood proteins ▫ Produced by liver ▫ Influence: • Globulins ▫ Alpha and beta Transport: ▫ Gamma Antibodies ▫ Fibrinogen Clotting mechanism FORMED ELEMENTS: ERYTHROCYTES • Function ▫ Production of hemoglobin ▫ Carries oxygen ▫ Carries 20% of CO2 ▫ Blood viscosity 7.5 m • Structure ▫ Biconcave shape ▫ 97% hemoglobin (excluding H2O) ▫ 250 to 280 million hemoglobin molecules/ RBC 2.0 m HEMOGLOBIN • 12 to 16 g/100 ml blood in females • 13 to 18 g/100 ml in males • Composed of: 2 1 2 1 heme ▫ Globin protein ▫ Heme pigment • Binds oxygen • May also bind to carbon dioxide (CO2) or carbon monoxide (CO) HEMOGLOBIN • 4 globin chains, each bound to a heme group Iron atom at the center of heme Iron binds O2 4 O2 per hemoglobin molecule Forms oxyhemoglobin in the lungs Releases O2 in tissues to become deoxyhemoglobin CO2 may bind to globin to form carbaminohemoglobin 2 1 2 1 heme ERYTHROCYTE PRODUCTION(ERYTHROPOIESIS) • In red bone marrow • Epiphyses of femur and humerus, spongy bone of sternum and hip • Stimulated by erythropoietin (EPO) • Formed elements arise from the same stem cell in the bone marrow ERYTHROCYTE PRODUCTION(ERYTHROPOIESIS) Hemocytoblast Committed to become an RBC Begins hemoglobin production Nucleus is ejected 3 to 5 days Reticulocytes enter circulation Fully mature 2 days after entering circulation Reticulocyte counts ERYTHROPOIESIS • Over 2 million RBC’s produced/sec. • Iron and B vitamins necessary • Kidney cell hypoxia = EPO production ▫ Accelerated RBC production triggered by: RBC numbers oxygen availability oxygen demand by tissues • Testosterone enhances erythropoietin production REGULATION OF ERYTHROPOIESIS Start Increases O2carrying ability of blood Reduces O2 levels in blood Enhanced erythropoiesis increases RBC count Erythropoietin stimulates re bone marrow Stimulus: Hypoxia due to decreased availability of O2 t o blood, or increased tissue demands for O2 Kidney releases erythropoietin ERYTHROCYTE DESTRUCTION • RBC lifespan: • Old RBC’s: ▫ Cell fragments destroyed by macrophages in the liver and spleen ▫ Hemoglobin globin and heme ▫ Globin amino acids ▫ The iron of the heme group reuse ▫ Rest becomes bilirubin (pigment) ▫ Bilirubin secreted in bile from the liver into the small intestine ERYTHROCYTE DISORDERS • Anemias ▫ oxygen carrying capacity ▫ Fatigue, chills, dizziness, shortness of breath ▫ Causes: 1 Reduced number of RBC’s Blood loss, RBC destruction, bone marrow failure Three types: ▫ Hemorrhagic anemia ▫ Hemolytic anemia ▫ Aplastic anemia (abnormalities in marrow) ERYTHROCYTE DISORDERS • Anemias ▫ Causes of anemia (continued) 2 Decreased hemoglobin Iron deficiency Athlete’s anemia Pernicious anemia (B12 deficiency) ▫ Intrinsic factor ERYTHROCYTE DISORDERS • Anemias ▫ Causes of anemia (continued) 3 Abnormal hemoglobin Thalassemia ▫ Genetic- Mediterranean descent ▫ Depressed globin synthesis- reduced RBC count Sickle cell anemia Genetic- ancestors in the malaria belt Abnormal hemoglobin RBC’s collapse / sickle-shaped ERYTHROCYTE DISORDERS • Polycythemia vera ▫ erythrocytes ▫ Dizziness, high RBC count (hematocrit may be 80%), viscous blood, impaired circulation bone marrow cancer blood doping or use of EPO LEUKOCYTES • • • • • Complete, nucleated cells Less than 1% of blood volume (4,000 to 11,000 / mm3) Protect body from: Use diapedesis Amoeboid movement capillary connective tissue leukocyte LEUKOCYTE PERCENTAGES Neutrophil (40-70%) Erythrocytes Blood FORMED ELEMENTS Granulocytes Eosinophil (1-4%) Leukocytes Basophil (0-1%) Lymphocyte (20-45%) Platelets Agranulocytes Monocyte (4-8%) GRANULOCYTES • Neutrophils ▫ Most numerous ▫ Phagocytize bacteria GRANULOCYTES • Eosinophils ▫ Fight parasites ▫ Inactivation of some inflammatory chemicals GRANULOCYTES • Basophils ▫ Least numerous ▫ Histamine and heparin release AGRANULOCYTES • Lymphocytes ▫ Immune response Direct attack Antibodies AGRANULOCYTES • Monocytes ▫ Phagocytosis ▫ Chronic infections LEUKOCYTE DISORDERS • Leukocytosis ▫ WBC count (over 11,000 per mm3) bacterial or viral invasion leukemia and mononucleosis • Leukopenia ▫ WBC count drugs (especially glucocorticoids), chemotherapy, rheumatoid arthritis, cirrhosis of the liver • Leukemias ▫ ▫ ▫ ▫ Cancer: WBC’s Rapidly dividing WBC’s, unspecialized, nonfunctional normal bone marrow function Fever, weight loss, bone or organ pain, infections LEUKOCYTE DISORDERS • Mononucleosis ▫ ▫ ▫ ▫ ▫ Contagious viral infection Children and young adults Epstein-Barr virus agranulocyte numbers Fatigue, aches, sore throat, low grade fever • Differential White Blood Cell Count: THROMBOCYTES • • • • • Fragments of megakaryocytes No nucleus Temporary plug Life span < 10 days 250,000 to 500,000 / ml blood PLATELET PLUG FORMATION Injury to lining of vessel exposes collagen fibers; platelets adhere Fibrin clot with trapped RBC’s Platelet plug forms collagen fibers PF3 from platelets & tissue thromboplastin from damaged tissue cells fibrin platelets + Ca2+ & other clotting factors in blood plasma Formation of PROTHROMBIN ACTIVATOR PROTHROMBIN THROMBIN FIBRINOGEN FIBRIN CLOTTING AND BLEEDING DISORDERS • Hemophilia ▫ Inherited ▫ clotting time missing clotting factors VIII or IX • Thrombocytopenia ▫ platelet numbers ▫ Bleeding from small vessels • Thrombus ▫ Clot develops in unbroken vessel blocks circulation • Embolus ▫ Traveling thrombus Trapped in smaller blood vessels BLOOD TYPES • Protein antigens on RBC plasma membrane: ▫ B, A or no antigens (Type O) • Other Rh antigens • Antibodies attack antigen not recognized by the body • Results in agglutination and hemolysis with nonmatching blood type Type A blood of donor Type A antibody in Type B blood of recipient Antigen & antibody match Agglutination ABO BLOOD GROUPS Antigen A Antigen B Antigen AB Antibody B Antibody A Neither Antibody A nor B Antibody A and B TYPE A TYPE B TYPE AB TYPE O Neither Antigen A nor B ABO BLOOD GROUPS • Universal Donor ▫ Neither A nor B antigens ▫ Type O blood • Universal Recipient ▫ A and B antigens ▫ Type AB blood ERYTHROBLASTOSIS FETALIS • Rh+ fetus / Rh- mother • Fetal organ damage FIRST PREGNANCY SECOND PREGNANCY maternal circulation (Rh-) fetal circulation (Rh+) (RH-) antibodies develop in the mother after delivery Agglutination of fetal (RH+) fetus