Hole’s Human Anatomy and Physiology Twelfth Edition Shier w Butler w Lewis Chapter 14 Blood Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 14.1: Introduction Blood: • Is connective tissue • Transports vital substances (Like what?) • Maintains stability of interstitial fluid • Distributes heat Blood cells: • Form mostly in red bone marrow and are: • Red blood cells (RBCs) • White blood cells (WBCs) • Platelets (cell fragments) • The amount of blood varies with body size, changes in fluid concentration, changes in electrolyte concentration, and amount of adipose tissue (Why these changes?) • Blood is about 8% of body weight • Adult blood volume is about 5 liters 2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Centrifuged Blood Sample Liquid (plasma) “Buffy coat” (white blood cells and platelets) Red blood cells Peripheral Blood Smear White blood cells Red blood cells Platelets 3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillary tube Plasma = 55% Buffy coat Red cells = 45% (hematocrit) Plug 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Blood 45% 55% Plasma Formed elements Platelets Red blood cells White blood cells (4.8%) (95.1%) (0.1%) Electrolytes Water (92%) Proteins Wastes Nutrients (7%) Gases Vitamins Hormones Neutrophils Eosinophils Basophils Monocytes Lymphocytes (54–62%) (1–3%) (<1%) (3–9%) (25–33%) Albumins Globulins Fibrinogen N2 O2 5 CO2 14.2: Blood Cells • Blood cells originate in red marrow from hemocytoblasts or hematopoietic stem cells • Stem cells can then: • Give rise to more stem cells • Specialize or differentiate 6 The Origin of Blood Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hematopoietic stem cell Myeloid stem cell Myeloblast Monoblast Megakaryoblast In red bone marrow Proerythroblast Lymphoid stem cell Lymphoblast T cell precursor Lymphoblast B cell precursor Progranulocyte Erythroblast Neutrophilic Basophilic Eosinophilic myelocyte myelocyte myelocyte Promonocyte Prolymphocyte Prolymphocyte Normoblast Megakaryocyte Reticulocyte Activated in tissues In circulating blood (some cells) Neutrophilic Basophilic Eosinophilic band cell band cell band cell Erythrocyte Thrombocytes (platelets) T lymphocyte Neutrophil Basophil Eosinophil Agranulocytes Granulocytes Macrophage (a) (b) B lymphocyte Monocyte Plasma cell 7 Characteristics of Red Blood Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Red blood cells are: • Erythrocytes • Biconcave discs • One-third hemoglobin or: • Oxyhemoglobin • Deoxyhemoglobin • Able to readily squeeze through capillaries • Lack nuclei and mitochondria – (Can they reproduce or metabolize?) Top view 7.5 micrometers 2.0 micrometers Sectional view (a) 8 (b) b: © Bill Longcore/Photo Researchers, Inc. 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 9 Red Blood Cell Production and Its Control Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Low blood oxygen causes the kidneys and the liver to release erythropoietin (EPO) which stimulates RBC production • This is a negative feedback mechanism (What does this mean?) • Within a few days many new blood cells appear in the circulating blood Low blood oxygen Liver Kidney Release into bloodstream Stimulation Inhibition – Erythropoietin Bloodstream + Increased oxygencarrying capacity Increased number of red blood cells 10 Red bone marrow Dietary Factors Affecting Red Blood Cell Production • Vitamin B12 and folic acid are necessary • They are required for DNA synthesis, making them necessary for the growth and division of all cells • Iron is also necessary • It is required for hemoglobin synthesis 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Red bone marrow Bone 3 Red blood cells produced Nutrients from food 2 Blood transports absorbed nutrients 1 Absorption Vitamin B12 Folic acid Iron 4 Red blood cells circulate in bloodstream for about 120 days 5 Macrophage Old red blood cells 6 Hemoglobin Blood Globin + Heme 7 Iron + Biliverdin Bile Liver Bilirubin Small intestine 8 12 Destruction of Red Blood Cells 13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (a) (b) a: © The McGraw-Hill Companies, Inc./Al Telser, photographer :b © Ed Reschke 14 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 15 Neutrophils • Light purple granules in acid-base (neutral) stain • Lobed nucleus • Other names • Segs • Polymorphonuclear leukocyte • Bands (young neutrophils) • First to arrive at infections • Phagocytic (What is this?) • 54% - 62% of leukocytes • Elevated in bacterial infections (Why?) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Ed Reschke 16 Eosinophils • Deep red granules in acid stain • Bi-lobed nucleus • Moderate allergic reactions • Defend against parasitic worm infestations • 1% - 3% of leukocytes • Elevated in parasitic worm infections and allergic reactions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Ed Reschke 17 Basophils • Deep blue granules in basic stain • Release histamine (What does this do?) • Release heparin (What does this do?) • Less than 1% of leukocytes • Similar to eosinophils in size and shape of nuclei Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Ed Reschke 18 Monocytes • Largest of all blood cells • Spherical, kidney-shaped, oval or lobed nuclei • May leave bloodstream to become macrophages • 3% - 9% of leukocytes • Phagocytize bacteria, dead cells, and other debris Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © R. Kessel/Visuals Unlimited 19 Lymphocytes • Slightly larger than RBC • Large spherical nucleus surrounded by thin rim of cytoplasm • T cells and B cells (Why are they named this?) • Both important in immunity • B cells produce antibodies • 25% - 33% of leukocytes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Ed Reschke 20 Functions of White Blood Cells • WBCs protect against infection • These leukocytes can squeeze between the cells of a capillary wall and enter the tissue space outside the blood vessel (called diapedesis) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Connective tissue Blood capillary Leukocyte 21 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Splinter punctures epidermis 2 Bacteria are introduced into the dermis 3 Bacteria multiply 4 Injured cells release histamine, causing blood vessels to dilate Epidermis Dermis Blood vessels 5 Neutrophils move through blood vessel walls and migrate toward bacteria 6 Neutrophils destroy bacteria by phagocytosis 22 White Blood Cell Counts • A procedure used to count number of WBCs per cubic millimeter of blood • Typically 5,000 – 10,000 per cubic millimeter of blood • Leukopenia: • Low WBC count (below 5,000) • Typhoid fever, flu, measles, mumps, chicken pox, AIDS (Why?) • Leukocytosis: • High WBC count (above 10,000) • Acute infections, vigorous exercise, great loss of body fluids (Why?) • Differential WBC count • Lists percentages of types of leukocytes 23 • May change in particular diseases 24 Blood Platelets • Platelets are also known as thrombocytes • They are cell fragments of megakaryocytes • They lack a nucleus and are roughly half the size of a RBC • There are approximately 130,000 – 360,000 per cubic millimeter of blood • They help repair damaged blood vessels by sticking to broken surfaces 25 26 14.3: Blood Plasma • Blood plasma is: • Straw colored • The liquid portion of blood • 55% of blood volume • 92% water • Function includes transporting nutrients, gases, and vitamins • Helps regulate fluid and electrolyte balance and maintain pH (How?) 27 Plasma Proteins • These are the most abundant dissolved substances (solutes) in plasma 28 Gases and Nutrients • The most important blood gases: • Oxygen • Carbon dioxide • Plasma nutrients include: • Amino acids • Simple sugars • Nucleotides • Lipids • Fats (triglycerides) • Phospholipids • Cholesterol 29 Nonprotein Nitrogenous Substances • These are molecules containing nitrogen but are not proteins • In plasma they include: • Urea – product of protein catabolism; about 50% of nonprotein nitrogenous substances (What’s catabolism?) • Uric acid – product of nucleic acid catabolism (When would this happen?) • Amino acids – product of protein catabolism • Creatine – stores phosphates (For what purposes?) • Creatinine – product of creatine metabolism • BUN – blood urea nitrogen; indicates health of kidney (Why is this an indicator of kidney health?) 30 Plasma Electrolytes • Plasma contains a variety of these ions called electrolytes • They are absorbed from the intestine or released as byproducts of cellular metabolism (What are they used for?) • They include: • Sodium (most abundant with chloride) • Potassium • Calcium • Magnesium • Chloride (most abundant with sodium) • Bicarbonate • Phosphate • Sulfate 31 14.4: Hemostasis • Hemostasis refers to the stoppage of bleeding • Actions that limit or prevent blood loss include: • Blood vessel spasm • Platelet plug formation • Blood coagulation 32 Blood Vessel Spasm • Blood vessel spasm • Triggered by pain receptors, platelet release, or serotonin • Smooth muscle in blood vessel contracts (What does this do?) 33 Platelet Plug Formation • Platelet plug formation • Triggered by exposure of platelets to collagen • Platelets adhere to rough surface to form a plug Copyright © The McGraw-Hill Companies, Inc. 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Endothelial lining Collagen fiber 1 Break in vessel wall Platelet Red blood cell 2 Blood escaping through break 3 Platelets adhere to each othe , to end of broken vessel, and to exposed collagen 4 Platelet plug helps control blood loss 34 Blood Coagulation • Blood coagulation • Triggered by cellular damage and blood contact with foreign surfaces • A blood clot forms • This is a: • Hemostatic mechanism • Causes the formation of a blood clot via a series of reactions which activates the next in a cascade • Occurs extrinsically or intrinsically 35 36 Extrinsic Clotting Mechanism • Extrinsic clotting mechanism • Chemical outside of blood vessel triggers blood coagulation • Triggered by tissue thromboplastin (factor III) (not found in blood) • A number of events occur that includes factor VII, factor X, factor V, factor IV, and factor II (prothrombin) • Triggered when blood contacts damaged blood vessel walls or tissues • This is an example of a positive feedback mechanism (Why? How does this differ from a negative feedback mechanism?) 37 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © SPL/Photo Researchers, Inc. 38 Intrinsic Clotting Mechanism • Intrinsic clotting mechanism • Chemical inside blood triggers blood coagulation • Triggered by Hageman factor XII (found inside blood) • Factor XII activates factor XI which activates IX which joins with factor VIII to activate factor X • Triggered when blood contacts a foreign surface (Can you think of an example?) 39 40 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extrinsic Clotting Mechanism Intrinsic Clotting Mechanism Tissue damage Blood contacts foreign surface Releases Activates Tissue thromboplastin (Factor lll) Activates Hageman Factor Xll (Ca+2) Activates Factor Vll Activates Factor Xl (Ca+2) Activates Factor X Factor lX Activates Factor V (Ca+2) Activates Factor Vlll platelet phospholipids Factor X (Ca+2) Activates Factor V (Ca+2) Prothrombin activator Converts Thrombin (Factor lla) Prothrombin (Factor ll) Converts Fibrinogen (Factor l) Fibrin Factor Xlll Stabilizes 41 Fibrin clot Fate of Blood Clots • After a blood clot forms it retracts and pulls the edges of a broken blood vessel together while squeezing the fluid serum from the clot • Platelet-derived growth factor stimulates smooth muscle cells and fibroblasts to repair damaged blood vessel walls • Plasmin digests the blood clots • A thrombus is an abnormal blood clot • An embolus is a blood clot moving through the blood vessels 42 Prevention of Coagulation • The smooth lining of blood vessels discourages the accumulation of platelets and clotting factors • As a clot forms fibrin absorbs thrombin and prevents the clotting reaction from spreading • Anti-thrombin inactivates additional thrombin by binding to it and blocking its action on fibrinogen • Some cells such as basophils and mast cells secrete heparin (an anticoagulant) 43 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lumen (a) Artery wall Lumen Plaque Artery wall (b) © The McGraw-Hill Companies, Inc./Al Telser, photographer 44 45 14.5: Blood Groups and Transfusions • In 1910, identification of the ABO blood antigen gene explained the observed blood type incompatibilities • Today there are 31 different genes known to contribute to the surface features of RBCs determining compatibility between blood types 46 Antigens and Antibodies • Terms to become familiar with: • Agglutination – clumping of red blood cells in response to a reaction between an antibody and an antigen • Antigens – a chemical that stimulates cells to produce antibodies • Antibodies – a protein that reacts against a specific antigen 47 ABO Blood Group • Based on the presence or absence of two major antigens on red blood cell membranes • Antigen A • Antigen B 48 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Red blood cell Red blood cell Anti-B antibody Anti-A antibody Antigen A Antigen B Type B blood Type A blood Red blood cell Anti-A antibody Anti-B antibody Antigen A Antigen B Red blood cell Type AB blood Type O blood 49 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Red blood cell Agglutinated red blood cells Antigen A Anti-B antibody (a) (c) Anti-A antibody (b) (d) c: © G.W. Willis/Visuals Unlimited; figure d: © George W. Wilder/Visuals Unlimited 50 51 Rh Blood Group • The Rh blood group was named for the rhesus monkey • The group includes several Rh antigens or factors • Rh positive – presence of antigen D or other Rh antigens on the red blood cell membranes • Rh negative – lack of these antigens • The seriousness of the Rh blood group is evident in a fetus that develops the condition erythroblastosis fetalis or hemolytic disease of the newborn (How does this happen?) 52 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – – – – – – – – – – –– – – – – – – – – – – – – – –– – – – – – – – – – – – – – – + – – – – + + – – + + + – + – + – + – – – – Rh-negative woman with Rh-positive fetus – – – – – – – – – – –– – – – – – – – – – – – – – –– – – – – – – – – ++ + – ++ – + – + + + – + + + + + + – + – + + – + – – Cells from Rh-positive fetus enter woman’s bloodstream ––– – – –– – – – – – – – – – – –– – – – – – – – –– – – – –– – – –– – – – – – – – – – – – – – – – + – – – – – – – Woman becomes sensitized— antibodies ( + ) form to fight Rh-positive blood cells ––– – – –– – – – – – – – – – – –– – – – – – – – –– – – – –– – – –– – – – – – – – – – – – – – – – – – In the next Rh-positive pregnancy, maternal antibodies attack fetal red blood cells 53 Important Points in Chapter 14: Outcomes to be Assessed 14.1: Introduction Describe the general characteristics of blood and discuss its major functions. Distinguish among the formed elements of blood and the liquid portion of blood. 14.2: Blood Cells Describe the origin of blood cells. Explain the significance of red blood cells counts and how they are used to diagnose disease. Discuss the life cycle of a red blood cell. Summarize the control of red blood cell production. 54 Important Points in Chapter 14: Outcomes to be Assessed Distinguish among the five types of white blood cells and give the function(s) of each type. Describe a blood platelet and explain its functions. 14.3: Blood Plasma Describe the functions of each of the major components of plasma. 14.4: Hemostasis Define hemostasis and explain the mechanisms that help to achieve it. Review the major steps in coagulation. Explain how to prevent coagulation. 55 Important Points in Chapter 14: Outcomes to be Assessed 14.5: Blood Groups and Transfusions Explain blood typing and how it is used to avoid adverse reactions following blood transfusions. Describe how blood reactions may occur between fetal and maternal tissues. 56