Blood Chapter 19

Introduction Functions Composition Volume varies Transport medium Regulation Protection Composition Plasma – fluid Formed elements – cells & cell fragments Volume varies Average = 5 liters

Human Anatomy, 3rd edition Composition of Blood FG20_01.JPG Title: The Composition of Whole Blood Notes: The percentage ranges for white blood cells indicate the normal variation seen in a count of 100 white blood cells in a healthy individual. Keywords: whole blood, composition, plasma, formed elements, red blood cells, white blood cells, platelets, plasma proteins, electrolytes, organic nutrients, wastes Human Anatomy, 3rd edition Prentice Hall, © 2001

Plasma = about 55% of the blood Composition Mostly water Plasma proteins Dissolved foods, wastes, gases, ions Differences between plasma and intersititial fluid Plasma has more dissolved gases Plasma has more proteins Concentrations of small molecules are similar

Plasma Proteins Most are made by the liver Albumins – transport fatty acids & steroids Globulins – immune functions Fibrinogen – blood clotting

Formed Elements Blood cells and cell fragments Produced by hemopoiesis Arise from stem cells called hemocytoblasts Types of formed elements Erythrocytes – red blood cells (RBCs) Leukocytes – white blood cells (WBCs) Thrombocytes – platelets

Human Anatomy, 3rd edition Erythrocytes Biconcave Have no nuclei (or other organelles) Functional for about 120 days Production occurs in the red bone marrow Erythropoiesis Controlled by erythropoietin Functions Transport O2 & some CO2 Human Anatomy, 3rd edition Prentice Hall, © 2001

Human Anatomy, 3rd edition SEM of RBCs SEMFG20_02C.JPG Title: Anatomy of Red Blood Cells Notes: (a)Standard red blood smear. (b)Rouleaux formation as red blood cells travel through a capillary. (c)SEM of red blood cells; 3-dimensional structure. (d)Sectional view of red blood cell. Keywords: red blood cell, rouleaux, capillary, sectional view Human Anatomy, 3rd edition Prentice Hall, © 2001

Human Anatomy, 3rd edition Hemoglobin Binds to oxygen & carbon dioxide Anemia Polycythemia (erythrocytosis) Human Anatomy, 3rd edition Prentice Hall, © 2001

Numbers of RBCs Normally 4.3-5.8 million cells/mm3 of blood Males = 5.1-5.8 million/mm3 Females = 4.3-5.2 million/mm3 Numbers affect viscosity of blood The percentage of erythrocytes, by volume, in whole blood is the hematocrit Males = 45% Females = 42%

Leukocytes About 5000 – 10,000/mm3 of blood Produced by leukopoiesis in red bone marrow Location – mostly in peripheral tissues Functions Defense against pathogens Removal of toxins, wastes, abnormal or damaged cells As large or larger than RBCs, contain nuclei

Types of WBCs Granulocytes have granules in their cytoplasm Neutrophils Eosinophils Basophils

Human Anatomy, 3rd edition A Neutrophil Neutrophils are phagocytic towards bacteria 55-65% of circulating WBCs FG20_05A.JPG Title: White Blood Cells Notes: Comparison of leukocytes as seen in blood smears. (a)Neutrophil. (b)Eosinophil. (c)Basophil. (d)Monocyte. (e)Lymphocyte. Platelets are visible in part (e) as small cellular fragments between the RBC's. Keywords: white blood cells, neutrophil, eosinophil, basophil, monocyte, lymphocyte, red blood cell, platelet Human Anatomy, 3rd edition Prentice Hall, © 2001

Human Anatomy, 3rd edition An Eosinophil Eosinophils are involved in allergic reactions and parasitic infections 2-4% of circulating WBCs FG20_05B.JPG Title: White Blood Cells Notes: Comparison of leukocytes as seen in blood smears. (a)Neutrophil. (b)Eosinophil. (c)Basophil. (d)Monocyte. (e)Lymphocyte. Platelets are visible in part (e) as small cellular fragments between the RBC's. Keywords: white blood cells, neutrophil, eosinophil, basophil, monocyte, lymphocyte, red blood cell, platelet Human Anatomy, 3rd edition Prentice Hall, © 2001

Human Anatomy, 3rd edition A Basophil Basophils exaggerate inflammation at the site of an injury Less than 1% of circulating WBCs FG20_05C.JPG Title: White Blood Cells Notes: Comparison of leukocytes as seen in blood smears. (a)Neutrophil. (b)Eosinophil. (c)Basophil. (d)Monocyte. (e)Lymphocyte. Platelets are visible in part (e) as small cellular fragments between the RBC's. Keywords: white blood cells, neutrophil, eosinophil, basophil, monocyte, lymphocyte, red blood cell, platelet Human Anatomy, 3rd edition Prentice Hall, © 2001

Types of WBCs Agranulocytes do not have granules in their cytoplasm Monocytes Lymphocytes

Human Anatomy, 3rd edition A Monocyte Monocytes are phagocytes and form the macrophages of the tissues 2-8% of the WBC population FG20_05D.JPG Title: White Blood Cells Notes: Comparison of leukocytes as seen in blood smears. (a)Neutrophil. (b)Eosinophil. (c)Basophil. (d)Monocyte. (e)Lymphocyte. Platelets are visible in part (e) as small cellular fragments between the RBC's. Keywords: white blood cells, neutrophil, eosinophil, basophil, monocyte, lymphocyte, red blood cell, platelet Human Anatomy, 3rd edition Prentice Hall, © 2001

Human Anatomy, 3rd edition A Lymphocyte Lymphocytes are responsible for specific immunity B lymphocytes produce antibodies T lymphocytes attack foreign cells directly 20-30% of the WBC population FG20_05E.JPG Title: White Blood Cells Notes: Comparison of leukocytes as seen in blood smears. (a)Neutrophil. (b)Eosinophil. (c)Basophil. (d)Monocyte. (e)Lymphocyte. Platelets are visible in part (e) as small cellular fragments between the RBC's. Keywords: white blood cells, neutrophil, eosinophil, basophil, monocyte, lymphocyte, red blood cell, platelet Human Anatomy, 3rd edition Prentice Hall, © 2001

Human Anatomy, 3rd edition Thrombocytes Formed from fragments of large cells called megakaryocytes Have no nuclei, lifespan is 10 – 12 days Number about 350,000/mm3 of blood Function Involved in the clotting mechanism Human Anatomy, 3rd edition Prentice Hall, © 2001

Origins & Differentiation of Blood Cells FG20_08.JPG Title: The Origins and Differentiation of Blood Cells Notes: Hemocytoblast stem cells give rise to myeloid and lymphoid stem cells. Myeloid stem cells produce progenitor cells, which divide to produce the various classes of blood cells. The graph indicates the primary locations of blood cell formation during embryo Keywords: blood cells, origins, differentiation, hemocytoblast, myeloid stem cells, progenitor cells, lymphoid stem cell, lymphocytes, monocytes, myelocytes, basophils, eosinophils, neutrophils, platelets, erythroblast, erythrocyte, reticulocyte, megakaryocyte Human Anatomy, 3rd edition Prentice Hall, © 2001

Human Anatomy, 3rd edition Blood Types Antigens are specific proteins on RBC membranes A, B, O, Rh Antigens are accompanied by antibodies in plasma Specific antibodies bind with antigens, cause agglutination Human Anatomy, 3rd edition Prentice Hall, © 2001