Blood PDF

Chapter 19 The Cardiovascular System: The Blood 1  About this Chapter Composition of Blood Various cell types, origin and roles Red blood cells, hemoglobin, RBCs life cycle How coagulation works 2 Blo...

Chapter 19 The Cardiovascular System: The Blood 1  About this Chapter Composition of Blood Various cell types, origin and roles Red blood cells, hemoglobin, RBCs life cycle How coagulation works 2 Blood composing Components of Blood 4 The Origin of Blood Cells process of blood cells formation is known as: hematopoiesis or hemopoiesis In the embryo hemopoiesis occurs in yolk sac, liver, spleen, thymus, lymph nodes & red bone marrow. In adult occurs only in red marrow of flat bones like sternum, ribs, skull & pelvis and ends of long bones 5  Erythropoiesis Erythrocytes are produced throughout whole life to replace dead cells. Characteristics of Red Blood Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Top view Red blood cells are: 7.5 micrometers Erythrocytes Biconcave discs 2.0 micrometers One-third hemoglobin or: Oxyhemoglobin (a Sectional view ) Deoxyhemoglobin Able to readily squeeze through capillaries Lack nuclei and mitochondria – (Can they reproduce or metabolize?) (b) b: © Bill Longcore/Photo Researchers, Inc. 7  Red Blood Cell Counts RBC counts is the number of RBCs in a cubic millimeter or microliter of blood It may vary depending on age and health Typical ranges include: 4,600,000 – 6,200,000 in males (Why so high?) 4,200,000 – 5,400,000 in adult females (Why so low?) 4,500,000 – 5,100,000 in children (Why more than women?) RBC counts reflect blood’s oxygen carrying capacity 8  Hematocrit Percentage of total blood volume occupied by blood cells (RBCs). female normal range 38 - 46% (average of 42%) male normal range 40 - 54% (average of 46%) Testosterone and erythropoietin (EPO) Anemia Drop in hematocrit value. Polycythemia too many RBCs (over 65%) dehydration, tissue hypoxia, blood doping in athletes or the use of EPO 9  Hemoglobin Globin protein consisting of 4 polypeptide chains One heme pigment attached to each polypeptide chain each heme contains an iron ion (Fe+2) that can combine reversibly with one oxygen molecule 10  Transport of O2, CO2 and Nitric Oxide Each hemoglobin molecule can carry 4 oxygen molecules from lungs to tissue cells Hemoglobin transports 23% of total CO2 waste from tissue cells to lungs for release combines with amino acids in globin portion of Hb Hemoglobin transports nitric oxide & helping in regulation of blood pressure and blood flow 11 RBC Life Cycle 12 Red Blood Cell Production and Its Control Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Low blood oxygen Low blood oxygen causes Release into bloodstream the kidneys and the liver to Liver Kidney Stimulation release erythropoietin Inhibition (EPO) which stimulates RBC production – This is a negative Erythropoietin feedback mechanism Increased (What does this mean?) Bloodstream oxygen- carrying Within a few days many capacity new blood cells appear in Increased the circulating blood + number of red blood cells Red bone marrow 13 Types of White Blood Cells White blood cells: Are leukocytes Protect against disease WBC hormones are interleukins and colony-stimulating factors which stimulate development There are five types of WBCs in two categories: Granulocytes Neutrophils Eosinophils Basophils Agranulocytes Lymphocytes 14  Neutrophils Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. First to arrive at infections Phagocytic (What is this?) 54% - 62% of leukocytes © Ed Reschke 15  Eosinophils Defend against parasitic Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. worm infestations 1% - 3% of leukocytes Elevated in parasitic worm infections and allergic reactions © Ed Reschke 16 Basophils Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Release histamine (What does this do?) Release heparin (What does this do?) Less than 1% of leukocytes © Ed Reschke 17  Monocytes Largest of all blood cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. May leave bloodstream to become macrophages 3% - 9% of leukocytes Phagocytize bacteria, dead cells, and other debris © R. Kessel/Visuals Unlimited 18  Lymphocytes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. T cells and B cells Both important in immunity B cells produce antibodies 25% - 33% of leukocytes © Ed Reschke 19 White Blood Cell Counts Typically 5,000 – 10,000 per cubic millimeter of blood Leukopenia: Low WBC count (below 5,000) Leukocytosis: High WBC count (above 10,000) Differential WBC count Lists percentages of types of leukocytes May change in particular diseases 20  Emigration Emigration is the process by which WBCs leave the blood stream, in which WBCs roll along endothelium, stick to it & squeeze between cells. Neutrophils & macrophages phagocytize bacteria & debris. Phagocytosis is stimulated by factors released from microbs like toxin and kinins such process is called chemotaxis 21 https://www.gluegrant.org/chemotaxi 22  Hemostasis Sequence of responses that stops bleeding in a quick & localized fashion when blood vessels are damaged Methods utilized to reduce bleeding: vascular spasm platelet plug formation blood clotting (coagulation = formation of fibrin threads) 23 1-Blood Vessel Spasm Blood vessel spasm Triggered by pain receptors, platelet release, or serotonin Smooth muscle in blood vessel contracts (What does this do?) 24 2-Platelet Plug Formation Platelet Adhesion Platelet Release Reaction Platelet Aggregation 25 3- Blood Clotting Pathways 26  http://education- portal.com/academy/lesson/blood- coagulation-and-wound-healing.html 27  Role of Vitamin K in Clotting Normal clotting requires adequate vitamin K fat soluble vitamin absorbed if lipids absorption is normal. absorption slowed if bile release is insufficient Required for synthesis of 4 clotting factors by hepatocytes factors II (prothrombin), VII, IX and X Produced by bacteria in large intestine 28  Fate of Blood Clots Fibrinolysis is the system whereby the fibrin clot is dissolved as the vessel heals in order to restore normal blood flow. Tissue Plasminogen Activators (t-PA), which convert Plasminogen (inactive) to Plasmin (active) are released from injured vessel walls. once plasmin is formed it digests fibrin threads and inactivates fibrinogen, prothrombin and factors V and XII. 29  Intravascular Clotting Thrombus clot (thrombus) forming in an unbroken blood vessel forms on rough inner lining of BV if blood flows too slowly (stasis) allowing clotting factors to build up locally & cause coagulation Embolus clot, air bubble or fat from broken bone in the blood pulmonary embolus is found in lungs Low dose aspirin blocks synthesis of thromboxane A2 & reduces inappropriate clot formation 30 31 Blood Groups and Blood Types 32  Hemolytic Disease of Newborn Rh negative mom and Rh+ fetus will have mixing of blood at birth Mom's body creates Rh antibodies unless she receives a RhoGam shot soon after first delivery, miscarriage or abortion RhoGam binds to loose fetal blood and removes it from body before she reacts In 2nd child, hemolytic disease of the newborn may develop causing hemolysis of the fetal RBCs 33 Universal Donors and Recipients People with type AB blood called “universal recipients” since have no antibodies in plasma People with type O blood cell called “universal donors” since have no antigens on their cells theoretically can be given to anyone 34