Y khoa - Dược - Chapter 27: The blood

27The BloodLearning Outcomes (cont.)27.1 Describe the components of blood, giving the function of each component listed.27.2 Explain how bleeding is controlled. 27.3 Explain the differences among blood types A, B, AB, and O; including in the discussion which blood types are compatible.Learning Outcomes (cont.)27.4 Explain the difference between Rh- positive blood and Rh-negative blood. 27.5 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the blood.IntroductionBlood 4-6 liters per adult ~ 8% of body weightEssential functionsCarries oxygen and nutrientsRemoves carbon dioxide and wastesTransport mechanism for hormonesRegulation of body temperatureComponents of BloodRed blood cells – erythrocytes Small biconcave-shaped cells Small enough to pass through capillariesBlood Components (cont.)Hematocrit The percentage of red blood cellsNormally about 45%White cells and platelets = 1%Plasma = 55%Blood Components (cont.)Hemoglobin Oxyhemoglobin carries oxygenDeoxyhemoglobin ~ carries carbon dioxideRBC count Normally between 4 million and 6.5 million RBC/mlAnemia Blood Components (cont.)RBCs Produced in the red bone marrowLife span ~ 120 daysErythropoietin Produced by kidneysStimulates bone marrow Released when oxygen concentrations are lowBlood Components (cont.)RBC productionIronVitamin B12 Folic acidAging RBCsDestroyed by macrophages in liver and spleenBiliverdin released and converted to bilirubin by the liverWhite Blood Cells Leukocytes - WBCsGranulocytesNeutrophils – 55% Eosinophils – 3%Basophils – < 1%White Blood Cells AgranulocytesMonocytes [8%] – destroy bacteria, viruses, and toxins in blood Lymphocytes [33%] – provide immunity for the body White Blood Cells (cont.)WBC count normally 5000 to 10,000 WBCs per cubic millimeterLeukocytosis – highLeukopenia – low Diapedesis Blood PlateletsAlso called thrombocytes Fragments of cells Needed for the clotting process Normal count – 130,000 to 360,000 platelets per cubic millimeter of blood   Blood PlasmaWater ProteinsAlbumins ~ help to maintain blood pressureGlobulins ~ transport lipids and fat-soluble vitaminsFibrinogen ~ needed for blood clottingSerumBlood Plasma (cont.)NutrientsAmino acidsGlucoseNucleotidesLipidsGases OxygenCarbon dioxideNitrogenBlood Plasma (cont.)ElectrolytesNon-protein nitrogenous substancesWaste productsApply Your KnowledgeTrue or False:__ Hematocrit is the percentage of WBCs in the blood.__ Neutrophils destroy bacteria, viruses, and toxins in the  bloodstream. __ Platelets are important to the clotting process.__ Albumin is a small plasma protein that pushes water out of the  bloodstream. RBCs are biconcave-shaped cells and have hemoglobin rather  than a nucleus.pulls water intoRBCsTTFFANSWER:Bloody Great!TBleeding ControlHemostasis – the control of bleedingThree processes of hemostasisBlood vessel spasmPlatelet plug formationBlood coagulationBleeding Control (cont.)Bleeding Control (cont.)CoagulationFibrinogen converts to fibrinFibrin sticks to damaged areaFibrin meshwork traps blood cells and plateletsBlood clot stops bleedingBleeding Control (cont.)Thrombus – clot in a vessel with no known injuryEmbolusThrombus that breaks off and moves through blood streamDanger of blocking arteryPulmonary embolismMyocardial infarctionCVAApply Your KnowledgeARTERIES: Hemostasis occurs to control bleeding. First the blood vessel spasms, then a platelet plug forms, and lastly, the blood coagulates forming a blood clot.Explain what happens when a blood vessel is injured?YIPPEE!ABO Blood TypesBlood types are distinguished by antigens and antibodiesAgglutinationClumping of red blood cells Antigens on surface of RBCs bind to antibodies in plasmaBlood Types (cont.)Blood Types (cont.)Blood TypeAntigen on RBCAntibody in PlasmaBlood That Can Be ReceivedAABA and OBBAB and OABA and BNoneA, B, AB, and O ONoneA and BOApply Your KnowledgeIdentify the blood type:Truly Terrific!ANSWER:1432Rh FactorRh antigen Rh-positive Rh-negative Transfused bloodMatch for Rh factor1st unmatched transfusion ~ antibodies develop2nd time ~ agglutinationRh FactorErythroblastosis fetalis Mother developed antibodies to the Rh antigen in prior pregnancyAntibodies attack fetus’ bloodInfant ~ severe anemiaRh Factor (cont.)Apply Your KnowledgeANSWER: Rh-positive blood contains the Rh antigen while Rh-negative blood does not. If a person with Rh-negative blood receives a transfusion of Rh-positive blood, he will develop antibodies to the Rh antigen. If he receives any subsequent transfusions of Rh-positive, agglutination will occur.What is the difference between Rh-positive and Rh-negative blood and why is it important to know whether a person is RH-positive or negative before transfusing blood?Bravo!Diseases and Disorders of the Blood SystemDiseaseDescriptionAnemiaThe blood does not have enough RBCs or hemoglobin to carry an adequate amount of oxygen to the body’s cells LeukemiaBone marrow produces a large number of abnormal WBCsSickle cell anemiaAbnormal hemoglobin causes RBCs to change to a sickle shape; abnormal cells stick in capillariesDiseases and Disorders of the Blood System (cont.)DiseaseDescriptionPolycythemia veraDisease of the bone marrow that results in an abnormally high number of blood cells, especially RBCs, causing the blood to thickenThalassemiaInherited form of anemia; defective hemoglobin chain causes, small, pale, and short-lived RBCsApply Your KnowledgeANSWER: Anemia is a condition in which a person does not have enough red blood cells or hemoglobin in the blood to carry an adequate amount of oxygen to body cells. The doctor has told your patient she has anemia. How would you explain this to her?Way to go!In Summary27.1. The formed elements in blood include: red blood cells that are responsible for oxygen and carbon dioxide transport; white blood cells that are responsible for working with the immune system by fighting infection; and platelets, which assist in blood clotting. The liquid component of blood is called plasma and when all clotting factors and formed elements are spun out of plasma, the remaining liquid is called serum.In Summary (cont.)27.2 Hemostasis refers to the control of bleeding. Three basic processes occur during hemostasis: 1. blood vessel spasm; 2. platelet plug formation; and 3. blood coagulation. Clot formation is coagulation. It involves fibrinogen converting to fibrin, which sticks to the damaged area of the blood vessel, creating a meshwork that entraps blood cells and plateletsIn Summary (cont.)27.3 The four blood types are: A, B, AB and O. The antibodies attached to each type (except AB, which has no antibodies) require that each blood type receive only its specific antigen type during transfusions. So, A receives A or O; B receives B or O; AB as the universal receiver can receive any blood type; and O, although the universal donor, may receive only type O blood.In Summary (cont.)27.4 Rh factor is an antigen that may be attached to any blood type. Its importance arises during transfusions (Rh- negative blood cannot receive Rh-positive blood) and also during pregnancy if the mother is Rh- negative but the fetus received the Rh-positive antigen from the father. The effect on the first fetus will be little, but unless treated, any subsequent Rh-positive fetus will suffer effects of erythroblastosis fetalis, as the mother’s blood developed antibodies against the Rh-positive factor during the initial pregnancy.In Summary (cont.)27.5 There are many different types of blood diseases described within this chapter. The signs, symptoms, and treatments are as varied as the diseases themselves. The Common Diseases and Disorders for the Blood System section of this chapter outlines the most common of these diseases, their signs and symptoms, as well as their treatments. End of Chapter 27The bond that links your true family is not one of blood, but of respect and joy in each other’s life.~ Richard Bach