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27. The Blood. Learning Outcomes (cont.). 27.1 Describe the components of blood, giving the function of each component listed. 27.2 Explain how bleeding is controlled.
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27 The Blood
Learning Outcomes (cont.) 27.1Describe the components of blood, giving the function of each component listed. 27.2Explain how bleeding is controlled. 27.3Explain the differences among blood types A, B, AB, and O; including in the discussion which blood types are compatible.
Learning Outcomes (cont.) 27.4Explain 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.
Introduction • Blood • 4-6 liters per adult ~ 8% of body weight • Essential functions • Carries oxygen and nutrients • Removes carbon dioxide and wastes • Transport mechanism for hormones • Regulation of body temperature
Components of Blood • Red blood cells – erythrocytes • Small biconcave-shaped cells • Small enough to pass through capillaries
Blood Components (cont.) • Hematocrit • The percentage of red blood cells • Normally about 45% • White cells and platelets = 1% • Plasma = 55%
Blood Components (cont.) • Hemoglobin • Oxyhemoglobin carries oxygen • Deoxyhemoglobin ~ carries carbon dioxide • RBC count • Normally between 4 million and 6.5 million RBC/ml • Anemia
Blood Components (cont.) • RBCs • Produced in the red bone marrow • Life span ~ 120 days • Erythropoietin • Produced by kidneys • Stimulates bone marrow • Released when oxygen concentrations are low
Blood Components (cont.) • RBC production • Iron • Vitamin B12 • Folic acid • Aging RBCs • Destroyed by macrophages in liver and spleen • Biliverdin released and converted to bilirubin by the liver
White Blood Cells • Leukocytes - WBCs • Granulocytes • Neutrophils – 55% • Eosinophils – 3% • Basophils – < 1%
White Blood Cells • Agranulocytes • Monocytes [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 millimeter • Leukocytosis – high • Leukopenia – low • Diapedesis
Blood Platelets • Also called thrombocytes • Fragments of cells • Needed for the clotting process • Normal count – 130,000 to 360,000 platelets per cubic millimeter of blood
Blood Plasma • Water • Proteins • Albumins ~ help to maintain blood pressure • Globulins ~ transport lipids and fat-soluble vitamins • Fibrinogen ~ needed for blood clotting • Serum
Blood Plasma (cont.) • Nutrients • Amino acids • Glucose • Nucleotides • Lipids • Gases • Oxygen • Carbon dioxide • Nitrogen
Blood Plasma (cont.) • Electrolytes • Non-protein nitrogenous substances • Waste products
Apply Your Knowledge True 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. ANSWER: RBCs F T T pulls water into F T Bloody Great!
Bleeding Control • Hemostasis – the control of bleeding • Three processes of hemostasis • Blood vessel spasm • Platelet plug formation • Blood coagulation
Bleeding Control (cont.) • Coagulation • Fibrinogen converts to fibrin • Fibrin sticks to damaged area • Fibrin meshwork traps blood cells and platelets • Blood clot stops bleeding
Bleeding Control (cont.) • Thrombus – clot in a vessel with no known injury • Embolus • Thrombus that breaks off and moves through blood stream • Danger of blocking artery • Pulmonary embolism • Myocardial infarction • CVA
Apply Your Knowledge Explain what happens when a blood vessel is injured? ARTERIES:Hemostasis occurs to control bleeding. First the blood vessel spasms, then a platelet plug forms, and lastly, the blood coagulates forming a blood clot. YIPPEE!
Blood types are distinguished by antigens and antibodies Agglutination Clumping of red blood cells Antigens on surface of RBCs bind to antibodies in plasma ABO Blood Types
Apply Your Knowledge ANSWER: Identify the blood type: 1 2 3 4 Truly Terrific!
Rh Factor • Rh antigen • Rh-positive • Rh-negative • Transfused blood • Match for Rh factor • 1st unmatched transfusion ~ antibodies develop • 2nd time ~ agglutination
Rh Factor • Erythroblastosis fetalis • Mother developed antibodies to the Rh antigen in prior pregnancy • Antibodies attack fetus’ blood • Infant ~ severe anemia
Apply Your Knowledge 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? ANSWER: 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. Bravo!
Apply Your Knowledge The doctor has told your patient she has anemia. How would you explain this to her? ANSWER: 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. Way to go!
In Summary 27.1. 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.) 27.2Hemostasis 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 platelets
In Summary (cont.) 27.3The 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.) 27.4Rh 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.) 27.5There 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 27 The bond that links your true family is not one of blood, but of respect and joy in each other’s life. ~ Richard Bach