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CHAPTER 14

CHAPTER 14. THE CARDIOVASCULAR SYSTEM: BLOOD. O BJECTIVES. List the components and functions of blood components. List the components and functions of blood plasma. Describe the various mechanisms that prevent blood loss. Understand blood typing and transfusions. FUNCTIONS OF BLOOD.

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CHAPTER 14

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  1. CHAPTER 14 THE CARDIOVASCULAR SYSTEM: BLOOD

  2. OBJECTIVES • List the components and functions of blood components. • List the components and functions of blood plasma. • Describe the various mechanisms that prevent blood loss. • Understand blood typing and transfusions.

  3. FUNCTIONS OF BLOOD • TRANSPORTATION • Oxygen • From lungs to cells • Carbon Dioxide • Waste product of cellular respiration • Nutrients • From gastrointestinal tract to body cells • Heat and Waste • Away from cells • Hormones • From endocrine glands to other body cells

  4. FUNCTIONS OF BLOOD • REGULATION • pH • Of body fluids • Body temperature • Heat-absorbing and coolant properties of water in blood plasma • Flow of water through skin for cooling • Water content of cells • Through blood osmotic pressure

  5. FUNCTIONS OF BLOOD • PROTECTION • Prevents blood loss through clotting • Combats microbes and toxins through action of certain phagocytic white blood cells or specialized plasma proteins • Interferon and complements are proteins that help protect against disease

  6. COMPONENTS OF WHOLE BLOOD • Viscosity (stickiness or thickness; resistance to flow) • greater than that of water • Temperature range 38C or 100.4F. • pH range between 7.35 and 7.45 • Is this alkaline or acidic? • 8% of total body weight. • Volume in average-sized adult male body • 5 to 6 liters or 1.5 gallons. • Volume in average-sized adult female body • 4 to 5 liters or 1.2 gallons.

  7. COMPONENTS OF WHOLE BLOOD • Whole blood composed of two portions • 55% blood plasma • Liquid containing dissolved substances • 45% formed elements • Cells and cell fragments • Hematocrit: percentage of total blood volume occupied by red blood cells (99% of formed elements are red blood cells) • Buffy coat:thin layer of platelets and pale colorless white blood cells; less than 1% of blood volume

  8. Blood Plasma • Straw-colored liquid left when formed elements removed from blood  blood plasma • Composition: • 91.5 % water • 7% proteins • 1.5% solutes • Principle solutes include: • Proteins (Albumins, Globulins, and Fibrinogen) • Nutrients • Hormones • Respiratory gases • Electrolytes • Waste products

  9. Formed Elements • Red Blood Cells (RBCs) • White Blood Cells (WBCs) • Granular leukocytes • Neutrophils • Eosinophils • Basophils • Agranular leukocytes • T and B lymphocytes and natural killer cells • Monocytes • Platelets

  10. Formation of Blood Cells • Hemopoiesis:process through which formed elements develop from pluripotent stem cells in red bone marrow • Before birth hemopoiesis occurs in yolk sac of an embryo • Fetal hemopoiesis occurs in the liver, spleen, thymus, and lymph nodes • Hemopoiesis during the last three months before birth occurs in red bone marrow and continues there throughout life

  11. Formation of Blood Cells • Red bone marrow is derived from mesenchymal cells called pluripotent stem cells • Hormones stimulate pluripotent stem cells into two other types of stem cells: • Myeloid stem cells • Differentiate into red blood cells, platelets, eosinophils, basophils, neutrophils, and monocytes • Lymphoid stem cells • Differentiate into T and B lymphocytes

  12. Red Blood Cells(RBCs) • Aka: ERYTHROCYTES • Hemoglobinoxygen-carrying pigment • Gives whole blood its red color • STRUCTURE OF RBCs: • Biconcave discs • 7-8µm in diameter (1µm = 1/25,000 of an inch) • No nuclei or other organelles • Cannot divide • Do no carry on any extensive metabolic activity • Composed of : • Selectively permeable plasma membrane • Cytosol • Hemoglobin • Healthy male has about 5.4 million RBCs/µL of blood • Healthy female has about 4.8 million RBCs/µL of blood

  13. RBC LIFE CYCLE • Live about 120 days • Wear and tear on plasma membrane squeezing through capillaries necessitates replacement…

  14. Macrophages in spleen, liver, and red bone marrow through the process of phagocytosisrupture worn-out red blood cells splitting apart the globinand hemeportions of hemoglobin. • Globin broken down into amino acids(to be used in protein synthesis). • Iron removed from heme portion associates with plasma protein called transferrrin. • Iron-transferrin complexgoes to red bone marrow for RBC precursor cells to use in hemoglobin synthesis. • IRON NEEDED FOR HEME PORTION OF HEMOGLOBIN, AMINO ACID NEEDED FOR GLOBIN. • Also needed: Vitamin B12_ and Intrinsic factor. • Intrinsic Factor protein produced in stomach lining • Erythropoiesisis the process in red bone marrow that results in production of new red blood cells. • Iron removed from heme, non-iron portion converted to hiliverdin, a green pigment, and then into bilirubin, a yellow-orange pigment. Bilirubinenters blood and is transported to the liver, where it is secreted into bile. Bile goes to small intestine then large intestine. • Bacteria in large intestine converts bilirubin into urobilinogen, which is absorbed back into the blood, and converted to a yellow pigment called urobilin, which is excreted in urine. Urobilinogen is eliminated in fecesin the form of a brown pigment called stercobilin.

  15. RBC PRODUCTION • Erythropoiesis formation of only RBCs in the red bone marrow of adults

  16. RBC PRODUCTION • Hypoxia DEFICIENCY OF OXYGEN

  17. WBC STRUCTURE AND TYPESSOME REVIEW… • Also called: leukocytes • Have nuclei but do not contain hemoglobin • Classified as granular or agranular depending on whether or not they contain granules. • Granular leukocytes include: • Neutrophils • Eosinophils • Basophils • Agranular leukocytes include: • Monocytes • Lymphocytes • B cells • T cells • Natural Killer Cells

  18. WBC FUNCTIONS • Main function: • Combat inflammation and infection • Through processes of : • Phagocytosis • Antibody production

  19. Natural Killer Cells…FYI

  20. WBC LIFE SPAN • Life span = few hours to a few days • Normal blood contains 5000 to 10,000 WBCs per µL

  21. WBC PRODUCTION • Developed in red bone marrowleukocytes • Monocytes and granular leukocytes develop from myeloid stem cells • T and B cells develop from lymphoid stem cells

  22. Platelets • Are derived from: • Pluripotent stem cells • Structure: • Disk-shaped fragment • Lack a nucleus • Normal blood contains 250,000 to 400,000 platelets/µL

  23. HEMOSTASIS • Hemostasis sequence of responses that stops bleeding when blood vessels are injured • Three mechanisms that reduce blood loss: • Vascular Spasm • Platelet Plug Formation • Blood Clotting (Coagulation) • Hemostasis averts hemorrhage in smaller blood vessels

  24. Read pages 359-361 • Complete notes for ‘Vascular Spasm’, ‘Platelet Plug Formation’, and ‘Clotting’ • BUT first…let’s watch this http://www.mhhe.com/biosci/esp/2002_general/Esp/folder_structure/tr/m1/s7/trm1s7_3.htm

  25. Vascular Spasm • Blood vessel damaged • Its smooth muscle wall contracts immediately • Initiated by pain receptors • Reduces blood loss • Few minutes to several hours • Then other hemostatic mechanisms begin to operate • Vasoconstriction narrowing of blood vessel; platelets accumulate at damage site-release chemicals to maintain vascular spasm

  26. Platelet Plug Formation • Plugs form when platelets come into contact with parts of a damaged blood vessel • Platelet Plug Formation process: • Platelet Adhesion • Platelets contact and stick to damaged blood vessel (collagen fibers of connective tissue underlying damaged endothelial cells) • Platelet Release Reaction • Result of adhesion = platelets activated; characteristics change; extend projections to connect and interact; interaction triggers release of chemicals from their vesicles; chemicals activate nearby platelets to sustain vascular spasm= decreased blood flow through injured vessel • Platelet Aggregation • Chemicals made platelets sticky so they stick together and gather (aggregation); eventually enough to form a mass called platelet plug; completely covers hole in damaged vessel; blood loss ceases

  27. Clotting • Serum: plasma minus clotting proteins • Clots are composed of a network of insoluble fibers (fibrin) filled with trapped formed elements • Coagulation: formation of fibrin threads in a series of chemical reactions • Thrombosis: if blood clots too easily may result in a clot in an unbroken blood vessel • Hemorrhage: if blood takes too long to clot = uncontrolled bleeding • Three stages of the clotting process: • Prothrombinase formed • It is then converted to prothrombin (plasma protein formed in liver with help of Vitamin K); then converted to thrombin • Thrombin converts soluble fibrinogen (plasma protein formed by liver) into soluble fibrin; fibrin forms threads of clot • CLOTTING FACTORS: Calcium ions, enzymes, and molecules associated with platelets or damaged tissues activate each other throughout the clotting process

  28. Clear Retraction and Blood Vessel Repair • Clot Retraction: consolidation or tightening of fibrin to reduce further damage • Blood Vessel Repair: fibrin threads attached to damaged surfaces of blood vessels gradually contract as platelets pull them in; as clot retracts it pulls edges of vessel closer together = decreasing risk of further injury

  29. Hemostatic Control Mechanisms • Small, inappropriate clots dissolve through the process of fibrinolysis • What is the relationship between plasminogen and plasmin? • PLASMINOGEN IS AN INACTIVE PLASMA ENZYME; IS INCORPAORATED INTO A CLOT. • PLASMINOGEN IS ACTIVATED TO PLASMIN BY CERTAIN SUBSTANCES FOUND IN BOTH BODY TISSUES AND BLOOD. • PLASMIN IS AN ACTIVE PLASMA ENZYME, WHEN PLASMA IS FORMED IT CAN DISSOLVE CLOTS BY DIGESTING FIBRIN THREADS. • Heparin  _Anticoagulant; prevents blood clots • Warfarin (Coumadin) Antagonist to Vitamin K thus blocking synthesis of 4 clotting factors; also prevents clotting

  30. Clotting in Blood Vessels • Atherosclerosisaccumulation of fatty substances on arterial walls; result = roughening of endothelial surfaces of blood vessels; now possibility to blood clots forming when blood flows too slowly (allows clotting factors to accumulate) • Pulmonary Embolism embolism in the lungs; blood clot, bubble of air, fat from broken bones, or piece of debris are causes

  31. BLOOD GROUPS AND BLOOD TYPES • RBC surfaces are marked by genetically determined glycolipids and glycoproteins called isoantigensor agglutinogens. • distinguishes at least 24 different blood groups i.e. ABO, Rh, etc.

  32. ABO Blood Group • Based on two glycolipid isoantigens called A and B found on surface of RBCs. • If RBCs display only antigen A blood type Adisplay only antigen B blood type Bdisplay both antigens A & B blood type ABdisplay neither antigen blood type O • Plasma contains isoantibodies or agglutinins to the A or B antigens not found in your blood anti-A antibody reacts with antigen A anti-B antibody reacts with antigen B

  33. Rh Blood Group • Antigen was discovered in blood of Rhesus monkey • People with Rh isoantigens on RBC surface are Rh+. • People with no Rh isoantigens on RBC surface are Rh-. • Normal plasma contains no anti-Rh antibodies.

  34. RISK ASSOCIATED WITH Rh- MOTHERS • Rh negative mom and Rh+ fetus will have mixing of blood at birth thus the Mom's body creates Rh antibodies unless she receives a RhoGam shot soon after first delivery, miscarriage or abortion. In 2nd child, hemolytic disease of the newborn may develop causing hemolysis of the fetal RBCs

  35. Transfusions • Universal Donors and Recipients: • People with type AB blood called “UNIVERSAL RECIEPIENT” since have no antibodies in plasma. • People with type O blood cell called “UNIVERSAL DONOR” since have no antigens on their cells theoretically can be given to anyone. • Transfusiontransfer of whole blood or blood components (RBCs only or plasma only) into the bloodstream

  36. Transfusion chart

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