Blood Physiology 1 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 Blood composin...

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 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 One-third hemoglobin or: 2.0 micrometers 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. 6  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 7  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 8  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 9 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 10 RBC Life Cycle 11 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 Release into bloodstream causes the kidneys and Liver Kidney Stimulation the liver to release Inhibition erythropoietin (EPO) which stimulates RBC – production Erythropoietin This is a negative feedback mechanism Increased oxygen- (What does this mean?) Bloodstream carrying capacity Within a few days many new blood cells appear in Increased number of the circulating blood red blood + cells Red bone marrow 12 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 Monocytes 13  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 14  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 15 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 16  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 17  Lymphocytes T cells and B cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Both important in immunity B cells produce antibodies 25% - 33% of leukocytes © Ed Reschke 18 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 19  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 20  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) 21 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?) 22  2-Platelet Plug Formation Platelet Adhesion Platelet Release Reaction Platelet Aggregation 23 3- Blood Clotting Pathways 24  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 25  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. 26  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 27 Blood Groups and Blood Types 28  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 29 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 30