Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 1 Chapter 17 Blood

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 2 Composition of Blood  Introduction (Figure 17-1)  Blood—made up of plasma and formed elements  Blood—complex transport medium that performs vital pickup and delivery services for the body  Blood—keystone of body’s heat-regulating mechanism  Blood volume  Young adult male has approximately 5 liters of blood  Blood volume varies according to age, body type, sex, and method of measurement

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 3 Formed Elements of Blood  Red blood cells (erythrocytes)  Description of mature red blood cells (RBCs) (Figure 17-4) Have no nucleus and are shaped like tiny, biconcave disks Have no nucleus and are shaped like tiny, biconcave disks Do not contain ribosomes, mitochondria, and other organelles typical of most body cells Do not contain ribosomes, mitochondria, and other organelles typical of most body cells Primary component is hemoglobin Primary component is hemoglobin Most numerous of the formed elements Most numerous of the formed elements  Function of RBCs RBCs’ critical role in the transport of oxygen and carbon dioxide depends on hemoglobin RBCs’ critical role in the transport of oxygen and carbon dioxide depends on hemoglobin Carbonic anhydrase—enzyme in RBCs that catalyzes a reaction that joins carbon dioxide and water to form carbonic acid Carbonic anhydrase—enzyme in RBCs that catalyzes a reaction that joins carbon dioxide and water to form carbonic acid Carbonic acid—dissociates and generates bicarbonate ions, which diffuse out of the RBC and serve to transport carbon dioxide in the blood plasma Carbonic acid—dissociates and generates bicarbonate ions, which diffuse out of the RBC and serve to transport carbon dioxide in the blood plasma

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 4 Formed Elements of Blood  Red blood cells (erythrocytes) (cont.)  Hemoglobin (Figure 17-5) Within each RBC are approximately 200 to 300 million molecules of hemoglobin Within each RBC are approximately 200 to 300 million molecules of hemoglobin Hemoglobin is made up of four globin chains, each attached to a heme molecule Hemoglobin is made up of four globin chains, each attached to a heme molecule Hemoglobin is able to unite with four oxygen molecules to form oxyhemoglobin to allow RBCs to transport oxygen where it is needed Hemoglobin is able to unite with four oxygen molecules to form oxyhemoglobin to allow RBCs to transport oxygen where it is needed A male has a greater amount of hemoglobin than a female A male has a greater amount of hemoglobin than a female Anemia—a decrease in number or volume of functional RBCs in a given unit of whole blood Anemia—a decrease in number or volume of functional RBCs in a given unit of whole blood

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 5 Formed Elements of Blood  Red blood cells (erythrocytes) (cont.)  Formation of red blood cells (review Figures 17-6 and 17-7) Erythropoiesis—entire process of RBC formation Erythropoiesis—entire process of RBC formation RBC formation begins in the red bone marrow with hemopoietic stem cells that go through several stages of development to become erythrocytes; entire maturation process requires approximately 4 days RBC formation begins in the red bone marrow with hemopoietic stem cells that go through several stages of development to become erythrocytes; entire maturation process requires approximately 4 days RBCs are created and destroyed at a rate of approximately 100 million per minute in an adult; homeostatic mechanisms operate to balance number of cells formed against number of cells destroyed RBCs are created and destroyed at a rate of approximately 100 million per minute in an adult; homeostatic mechanisms operate to balance number of cells formed against number of cells destroyed  Destruction of RBCs (Figure 17-8) Life span of a circulating RBC averages 105 to 120 days Life span of a circulating RBC averages 105 to 120 days Macrophage cells phagocytose the aged, abnormal, or fragmented RBCs Macrophage cells phagocytose the aged, abnormal, or fragmented RBCs Hemoglobin is broken down and amino acids, iron, and bilirubin are released Hemoglobin is broken down and amino acids, iron, and bilirubin are released

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 6 Formed Elements of Blood  White blood cells (leukocytes, WBCs) (review Table 17-1)  Granulocytes Neutrophils (review Figure 17-9)—make up approximately 65% of total WBC count in a normal blood sample; highly mobile and very active phagocytic cells; capable of diapedesis; cytoplasmic granules contain lysosomes Neutrophils (review Figure 17-9)—make up approximately 65% of total WBC count in a normal blood sample; highly mobile and very active phagocytic cells; capable of diapedesis; cytoplasmic granules contain lysosomes Eosinophils (review Figure 17-10)—account for 2% to 5% of circulating WBCs; numerous in lining of respiratory and digestive tracts; weak phagocytes; capable of ingesting inflammatory chemicals and proteins associated with antigen-antibody reaction complexes; provide protection against infections caused by parasitic worms and allergic reactions Eosinophils (review Figure 17-10)—account for 2% to 5% of circulating WBCs; numerous in lining of respiratory and digestive tracts; weak phagocytes; capable of ingesting inflammatory chemicals and proteins associated with antigen-antibody reaction complexes; provide protection against infections caused by parasitic worms and allergic reactions Basophils (review Figure 17-11)—account for only 0.5% to 1% of circulating WBCs; motile and capable of diapedesis; cytoplasmic granules contain histamine and heparin Basophils (review Figure 17-11)—account for only 0.5% to 1% of circulating WBCs; motile and capable of diapedesis; cytoplasmic granules contain histamine and heparin

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 7 Formed Elements of Blood  White blood cells (cont.)  Agranulocytes (Figures and 17-13) Lymphocytes—smallest of the WBCs; second most numerous type of WBC; account for approximately 25% of circulating WBCs; T lymphocytes and B lymphocytes have an important role in immunity—T lymphocytes directly attack an infected or cancerous cell, and B lymphocytes produce antibodies against specific antigens Lymphocytes—smallest of the WBCs; second most numerous type of WBC; account for approximately 25% of circulating WBCs; T lymphocytes and B lymphocytes have an important role in immunity—T lymphocytes directly attack an infected or cancerous cell, and B lymphocytes produce antibodies against specific antigens Monocytes—largest type of leukocyte; mobile and highly phagocytic cells Monocytes—largest type of leukocyte; mobile and highly phagocytic cells  WBC numbers—a cubic millimeter of normal blood usually contains 5,000 to 9,000 leukocytes, with different percentages for each type; WBC numbers have clinical significance because they change with certain abnormal conditions  Formation of WBCs (review Figure 17-6) Granular and agranular leukocytes mature from the undifferentiated hemopoietic stem cell Granular and agranular leukocytes mature from the undifferentiated hemopoietic stem cell Neutrophils, eosinophils, basophils, and a few lymphocytes and monocytes originate in red bone marrow; most lymphocytes and monocytes develop from hemopoietic stem cells in lymphatic tissue Neutrophils, eosinophils, basophils, and a few lymphocytes and monocytes originate in red bone marrow; most lymphocytes and monocytes develop from hemopoietic stem cells in lymphatic tissue

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 8 Formed Elements of Blood  Platelets (review Figure 17-12)  Structure In circulating blood, platelets are small, pale bodies that appear as irregular spindles or oval disks In circulating blood, platelets are small, pale bodies that appear as irregular spindles or oval disks Three important properties are agglutination, adhesiveness, and aggregation Three important properties are agglutination, adhesiveness, and aggregation Platelet counts in adults average 250,000 per mm 3 of blood; normal range is 150,000 to 400,000 per mm 3 Platelet counts in adults average 250,000 per mm 3 of blood; normal range is 150,000 to 400,000 per mm 3  Functions of platelets Important role in hemostasis and blood coagulation Important role in hemostasis and blood coagulation Hemostasis—refers to stoppage of blood flow; however, if injury is extensive, the blood-clotting mechanism is activated to assist Hemostasis—refers to stoppage of blood flow; however, if injury is extensive, the blood-clotting mechanism is activated to assist

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 9 Formed Elements of Blood  Platelets (cont.)  Platelet plug formation 1 to 5 seconds after injury to vessel wall, platelets adhere to damaged endothelial lining and to each other, forming a platelet plug 1 to 5 seconds after injury to vessel wall, platelets adhere to damaged endothelial lining and to each other, forming a platelet plug Temporary platelet plug is an important step in hemostasis Temporary platelet plug is an important step in hemostasis Normal platelets (positive charge) adhere to damaged capillary wall and underlying collagen fibers, which both have a negative charge Normal platelets (positive charge) adhere to damaged capillary wall and underlying collagen fibers, which both have a negative charge “Sticky platelets” form physical plug and secrete several chemicals involved in the coagulation process “Sticky platelets” form physical plug and secrete several chemicals involved in the coagulation process  Formation and life span of platelets (7 to 10 days)—formed in red bone marrow, lungs, and spleen by fragmentation of megakaryocytes

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 10 Blood Types (Blood Groups)  The ABO system (Figures to 17-17)  Every person’s blood belongs to one of four ABO blood groups  Named according to antigens present on RBC membranes Type A—antigen A on RBC Type A—antigen A on RBC Type B—antigen B on RBC Type B—antigen B on RBC Type AB—both antigen A and antigen B on RBC; known as universal recipient Type AB—both antigen A and antigen B on RBC; known as universal recipient Type O—neither antigen A nor antigen B on RBC; known as universal donor Type O—neither antigen A nor antigen B on RBC; known as universal donor

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 11 Blood Types (Blood Groups)  The Rh system (Figure 17-18)  Rh-positive blood—Rh antigen is present on the RBCs  Rh-negative—RBCs have no Rh antigen present  Anti-Rh antibodies are not normally present in blood; anti-Rh antibodies can appear in Rh-negative blood if it has come in contact with Rh-positive RBCs

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 12 Blood Plasma  Plasma—liquid part of blood; clear, straw-colored fluid; made up of 90% water and 10% solutes (Figure 17-19)  Solutes—6% to 8% of plasma solutes are proteins, consisting of three main compounds:  Albumins—helps maintain osmotic balance of the blood  Globulins—essential component of the immunity mechanism  Fibrinogen—key role in blood clotting  Plasma proteins have an essential role in maintaining normal blood circulation

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 13 Blood Clotting (Coagulation)  Mechanism of blood clotting—goal of coagulation is to stop bleeding and prevent loss of vital body fluid in a swift and sure method; the “classic theory” (Figure 17-20) is as follows:  “Classic theory” of coagulation advanced in 1905 Identified four components critical to coagulation: Identified four components critical to coagulation:  Prothrombin  Thrombin  Fibrinogen  Fibrin

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 14 Blood Clotting (Coagulation)  Mechanism of blood clotting (cont.)  Current explanation of coagulation involves three stages: (Figure 17-21) Stage I—production of thromboplastin activator by one or the other of the following: Stage I—production of thromboplastin activator by one or the other of the following:  chemicals released from damaged tissues (extrinsic pathway)  chemicals present in the blood (intrinsic pathway) Stage II—conversion of prothrombin to thrombin Stage II—conversion of prothrombin to thrombin Stage III—conversion of fibrinogen to fibrin and production of fibrin clot Stage III—conversion of fibrinogen to fibrin and production of fibrin clot

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 15 Blood Clotting (Coagulation)  Conditions that oppose clotting  Clot formation in intact vessels is opposed  Several factors oppose clotting Perfectly smooth surface of the normal endothelial lining of blood vessels does not allow platelets to adhere Perfectly smooth surface of the normal endothelial lining of blood vessels does not allow platelets to adhere Antithrombins—substances in the blood that oppose or inactivate thrombin; prevent thrombin from converting fibrinogen to fibrin; e.g., heparin Antithrombins—substances in the blood that oppose or inactivate thrombin; prevent thrombin from converting fibrinogen to fibrin; e.g., heparin

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 16 Blood Clotting (Coagulation)  Conditions that hasten clotting  Rough spot in the endothelium  Abnormally slow blood flow  Clot dissolution (Figure 17-22)  Fibrinolysis—physiological mechanism that dissolves fibrin  Fibrinolysin—enzyme in the blood that catalyzes the hydrolysis of fibrin, causing it to dissolve  Additional factors are presumed to aid clot dissolution; e.g., substances that activate profibrinolysin

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 17 The Big Picture: Blood and the Whole Body  Blood plasma transports substances, including heat, around the body, linking all body tissues together  Substances can be transported between almost any two points in the body  Blood tissue contains formed elements—blood cells and platelets  RBCs assist in the transport of oxygen and carbon dioxide  WBCs assist in the defense mechanisms of the whole body  Platelets prevent loss of the fluid that constitutes the internal environment

Mosby items and derived items © 2007, 2003 by Mosby, Inc.Slide 18 The Big Picture: Blood and the Whole Body  No organ or system of the body can maintain proper levels of nutrients, gases, or water without direct or indirect help from blood  Other systems assist the blood  Blood is useless unless it continues to transport, defend, and maintain balance