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
Figure 21.1 Composition of Blood
Composition of Blood Upon separation by centrifugation, blood has three factions: 1. represent ~ 44% of total blood volume 2. coat represents about 1% of total blood volume 3. represents ~ 55% of total blood volume
Figure 21.2 Composition of Blood
Figure 21.3 Blood Smear
Blood Plasma
Formed Elements The 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 is capable of reversibly transporting oxygen and carbon dioxide in the blood Hemoglobin consists of four globin protein molecules: 1. Two (α) chains 2. Two (ß) chains
Molecular Structure of Hemoglobin Figure 21.5
Hemoglobin Each of the four globins possesses a nonprotein 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 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. ABO Blood Types Antigen A Antigen B Antigens A and B Neither antigen A nor B Erythrocytes Anti-B antibodies Anti-A antibodies Neither anti-a nor anti-b antibodies Both anti-a and anti-b antibodies Plasma Blood type 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 AB Erythrocytes with both type A and type B surface antigens, and plasma with neither anti-a nor anti-b antibodies Type O Erythrocytes with neither type A nor type B surface antigens, but plasma with both anti-a and anti-b antibodies (a) Rh Blood Types Antigen D No antigen D Erythrocytes No anti-d antibodies Anti-D antibodies (after prior exposure) Plasma Figure 21.7 (b) Blood type Rh positive Erythrocytes with type D surface antigens and plasma with no anti-d antibodies 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
Agglutination Reaction Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Donor blood type + Recipient blood type = Agglutination reaction Antigen A + = Type A blood of donor (has surface antigena) Type A blood of recipient (contains anti-b antibodies) Antigen and antibody do not match No agglutination No clumping seen. Successful blood type match. Antigen A + = Type A blood of donor (has surface antigena) Type B blood of recipient (contains anti-a antibodies) Antigen and antibody match and connect Agglutination Clumping seen. Hemolysis occurs. Unsuccessful blood type match. (a) Agglutination test Type B recipient erythrocyte Blood from type A donor Anti-A antibody in recipient plasma Type A donor erythrocyte Agglutinated erythrocytes from type A donor block small vessels Figure 21.8 (b) Erythrocyte agglutination 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,, and entering a tissue. Leukocytes are attracted to a site of infection by molecules from damaged cells or invading pathogens. This attraction is called.
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. Table 21.3 Leukocytes LM 1600x Eosinophil LM 1600x LM 1600x Neutrophil Basophil Granulocytes Agranulocytes LM 1600x LM 1600x Lymphocyte Monocyte Type Characteristics Functions Approximate % GRANULOCYTES Neutrophils Nucleus is multilobed (as many as five lobes) Cytoplasm contains neutral or pale, distinct granules (when stained) Phagocytize pathogens, especially bacteria Release enzymes that target pathogens 50 70% of total leukocytes Eosinophils Basophils AGRANULOCYTES Lymphocytes Nucleus is bilobed Cytoplasm contains reddish or pink-orange granules (when stained) Nucleus is bilobed Cytoplasm contains deep blue-violet granules (when stained) Round or slightly indented nucleus (fills the cell in smaller lymphocytes) Nucleus is usually darkly stained Thin rim of cytoplasm surrounds nucleus Phagocytize antigen-antibody complexes and allergens Release chemical mediators to destroy parasitic worms Release histamine (vasodilator) and heparin (anticoagulant) during inflammatory or allergic reactions Attack pathogens and abnormal/infected cells Coordinate immune cell activity Produce antibodies 1 4% of total leukocytes 0.5 1% of total leukocytes 20 40% of total leukocytes 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 2 8% of total leukocytes
Platelets Irregular membrane-enclosed cellular fragments that represent shed cytoplasm from cells in the red bone marrow called 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 Red bone marrow Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Megakaryocyte Megakaryocytes LM 1600x (a) (b) Endothelial cells Proplatelets Platelets a: The McGraw-Hill Companies, Inc./Photo by Dr. Alvin Telser Figure 21.9
Blood Clot Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fibrin Platelets Erythrocytes SEM 4100x Figure 21.10 Reprinted by permission from Macmillan Publishers Ltd: Nature, Dr. John W. Weisel and Yuri Veklich. Vol. 413, Issue 4, Cover Image, October 2001. 2001 Nature Publishing Group
Hemopoiesis Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hemocytoblast (blood stem cell) Myeloid line Lymphoid line Myeloid stem cell Lymphoid stem cell Multi-CSF Multi-CSF Multi-CSF Erythropoiesis Thrombopoiesis Leukopoiesis Progenitor cell Progenitor cell GM-CSF B-lymphoblast T-lymphoblast Progenitor cell Proerythroblast Megakaryoblast Myeloblast M-CSF Monoblast EPO Early erythroblast Thrombopoietin G-CSF Promegakaryocyte Promyelocytes Late erythroblast M-CSF Promonocyte Thrombopoietin Normoblast Megakaryocyte Eosinophilic Basophilic Neutrophilic myelocyte myelocyte myelocyte Nucleus ejected Reticulocyte Erythrocyte Thrombopoietin Eosinophil Basophil Neutrophil Monocyte Platelets B-lymphocyte T-lymphocyte Figure 21.11
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.