Chapter 21 *Lecture Outline Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. *See separate FlexArt PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes.

Chapter 21 Outline General Composition and Functions of Blood Blood Plasma Formed Elements in the Blood Hemopoiesis: Production of Formed Elements

Introduction Blood serves many functions. Some examples are: Transportation of oxygen and carbon dioxide as well as nutrients and waste products Regulation of body temperature, pH, and fluid volume Protection by mounting an immune response and the production of antibodies

Composition of Blood Figure 21.1

Composition of Blood Upon separation by centrifugation, blood has three factions: 1. Erythrocytes—represent ~ 44% of total blood volume 2. Buffy coat—represents about 1% of total blood volume 3. Plasma—represents ~ 55% of total blood volume

Composition of Blood Figure 21.2

Blood Smear Figure 21.3

Blood Plasma

Formed Elements The hematocrit is the % of the volume of all formed elements in one’s blood It varies in females from 38%–46% and between 42%–56% in males

Erythrocytes Also referred to as red blood cells or RBCs, but this is a misnomer as mature RBCs lack nuclei and other organelles Figure 21.4

Erythrocytes Relatively small (7.5 μm in diameter) Unique biconcave shape As they pass through small blood vessels, they line up in single file termed a rouleau

Hemoglobin in Erythrocytes Every erythrocyte contains 280 million molecules of a red-pigmented protein called hemoglobin Hemoglobin is capable of reversibly transporting oxygen and carbon dioxide in the blood Hemoglobin consists of four globin protein molecules: 1.Two alpha (α) chains 2.Two beta (ß) chains

Molecular Structure of Hemoglobin Figure 21.5

Hemoglobin Each of the four globins possesses a nonprotein heme group containing an iron (Fe 2+ ) molecule. Each hemoglobin molecule can bind a combination of four oxygen/carbon dioxide molecules.

Recycling the Components of Aged or Damaged Erythrocytes Figure 21.6

Blood Type Figure 21.7 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Antigen B Anti-B antibodies No anti-D antibodies Antigen DNo antigen D ABO Blood Types Erythrocytes Plasma Blood type (a) (b) Erythrocytes Plasma Blood type Neither antigen A nor B Both anti-A and anti-B antibodies Neither anti-A nor anti-B antibodies Anti-A antibodies Type A Erythrocytes with type A surface antigens and plasma with anti-B antibodies Type B Erythrocytes with type B surface antigens and plasma with anti-A antibodies Type O Erythrocytes with neither type A nor type B surface antigens, but plasma with both anti-A and anti-B antibodies Type AB Erythrocytes with both type A and type B surface antigens, and plasma with neither anti-A nor anti-B antibodies Antigens A and BAntigen A Rh Blood Types Anti-D antibodies (after prior exposure) Rh negative Erythrocytes with no type D surface antigens and plasma with anti-D antibodies, only if there has been prior exposure to Rh positive blood Rh positive Erythrocytes with type D surface antigens and plasma with no anti-D antibodies

Agglutination Reaction Figure 21.8 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Donor blood typeRecipient blood type + + = = += Agglutination reaction No agglutination Antigen A A (a) Agglutination test (b) Erythrocyte agglutination Agglutination No clumping seen. Successful blood type match. Clumping seen. Hemolysis occurs. Unsuccessful blood type match. Type A blood of donor (has surface antigenA) Type B blood of recipient (contains anti-A antibodies) Antigen and antibody match and connect Type A blood of donor (has surface antigenA) Type A blood of recipient (contains anti-B antibodies) Antigen and antibody do not match Type B recipient erythrocyte Type A donor erythrocyte Agglutinated erythrocytes from type A donor block small vessels Blood from type A donor Anti-A antibody in recipient plasma a: © Jean Claude Revy-ISM/Phototake

Leukocytes Unlike erythrocytes, leukocytes possess a nucleus and organelles. They help initiate an immune response and defend the body against pathogens. They are 1.5 to 3 times larger than erythrocytes. They are capable of leaving the blood vessels, diapedesis, and entering a tissue. Leukocytes are attracted to a site of infection by molecules from damaged cells or invading pathogens. This attraction is called chemotaxis.

Classification of Leukocytes The five types of leukocytes are divided into two classes (granulocytes and agranulocytes) based on the presence or absence of visible organelles termed granules.

Leukocytes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. LM 1600x Basophil LM 1600x Monocyte LM 1600x Lymphocyte Neutrophil LM 1600x Eosinophil Granulocytes Agranulocytes 50–70% of total leukocytes 1–4% of total leukocytes 0.5–1% of total leukocytes 20–40% of total leukocytes 2–8% of total leukocytes Neutrophils Eosinophils Basophils Lymphocytes Monocytes Kidney-shaped or C-shaped nucleus Nucleus is generally pale staining Abundant cytoplasm around nucleus Can exit blood vessels and become macrophages Phagocytize pathogens, cellular debris, dead cells Attack pathogens and abnormal/infected cells Coordinate immune cell activity Produce antibodies AGRANULOCYTES TypeCharacteristicsFunctionsApproximate % Leukocytes Table 21.3 GRANULOCYTES Nucleus is multilobed (as many as five lobes) Cytoplasm contains neutral or pale, distinct granules (when stained) Nucleus is bilobed Cytoplasm contains reddish or pink-orange granules (when stained) Cytoplasm contains deep blue-violet granules (when stained) Nucleus is bilobed Round or slightly indented nucleus (fills the cell in smaller lymphocytes) Nucleus is usually darkly stained Thin rim of cytoplasm surrounds nucleus Phagocytize pathogens, especially bacteria Release enzymes that target pathogens Phagocytize antigen-antibody complexes and allergens Release chemical mediators to destroy parasitic worms Release histamine (vasodilator) and heparin (anticoagulant) during inflammatory or allergic reactions

Platelets Irregular membrane-enclosed cellular fragments that represent shed cytoplasm from cells in the red bone marrow called megakaryocytes Megakaryocytes are about 15× larger than erythrocytes Platelets are about ¼ the size of erythrocytes Platelets are involved in the clotting of blood

Platelets and Megakaryocytes Figure 21.9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Megakaryocyte Platelets Proplatelets Endothelial cells Megakaryocytes (a) LM 1600x (b) Red bone marrow a: © The McGraw-Hill Companies, Inc./Photo by Dr. Alvin Telser

Blood Clot Figure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fibrin Erythrocytes Platelets SEM 4100x Reprinted by permission from Macmillan Publishers Ltd: Nature, Dr. John W. Weisel and Yuri Veklich. Vol. 413, Issue 4, Cover Image, October © 2001 Nature Publishing Group

Hemopoiesis Figure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Myeloid line Lymphoid line Myeloid stem cellLymphoid stem cell Multi-CSF Thrombopoietin GM-CSF Proerythroblast Megakaryoblast Myeloblast M-CSF G-CSF EPO Progenitor cell Erythropoiesis Progenitor cell ThrombopoiesisLeukopoiesis Monoblast Early erythroblast Promyelocytes Promonocyte Promegakaryocyte B-lymphoblastT-lymphoblast Normoblast Reticulocyte ErythrocyteEosinophilBasophilNeutrophilMonocyte Megakaryocyte Platelets B-lymphocyteT-lymphocyte Neutrophilic myelocyte Basophilic myelocyte Eosinophilic myelocyte Nucleus ejected Late erythroblast Hemocytoblast (blood stem cell)

Erythropoiesis Erythropoiesis is the process of erythrocyte production. About 3 million erythrocytes are produced per second. During maturation all organelles within the erythrocyte, including the nucleus, degenerate leaving the erythrocyte with nothing more than a “bag of hemoglobin.”