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Chapter 10: Blood Blood general functions • transport of dissolved gases, nutrients, hormones, and metabolic wastes • regulation of pH, body temperature, ion composition of interstitial fluids • restriction of fluid loss at the injury site • defense against toxins and pathogens Blood components • Plasma-90% water – contains dissolved proteins – most made by the liver • Formed elements (cells) – RBCs – WBCs – platelets Blood Components Erythrocytes (RBCs) • move oxygen in blood to body's cells • anucleate • hemoglobin – binds oxygen • lifespan ~120 days • biconcave disc – increases surface area for gas exchange RBCs RBCs • Anemia – lowered oxygen carrying ability • low RBC count • low hemoglobin content in RBC – sickle cell (SCA) • genetic • RBCs rupture easily • one copy of gene helps against malaria • two copies of gene = SCA White Blood Cells (Leukocytes) • defense against disease • complete cells with nuclei and all organelles • fewer than RBCs – 4000-11000 per mm3 Leukocytes • Special features – capable of amoeboid movement – migrate out of bloodstream – respond by positive chemotaxis – capable of phagocytosis Leukocytes • granulocytes – have granules in cytoplasm – lobed nuclei • agranulocytes – do not have granules – spherical or kidney-shaped nuclei Basophils • rarest of WBCs • granules contain histamine • release enhances inflammation Eosinophil • • • • 1-4% of WBCs Stain red Bi-lobed nucleus Protect against parasites Neutrophil • account for 40-70% of circulating WBCs • multi-lobed nucleus • active phagocytes at areas of acute infection Monocyte • 4-8% of WBCs • remains in blood for 24hrs before becoming a macrophage in tissue • long-term clean up Lymphocyte • 20-45% of WBCs • note the round nucleus, little cytoplasm • immune response Platelets • fragments of megakaryocytes • needed for clotting process Blood cell formation (hematopoiesis) • red bone marrow • all formed elements arise from hemocytoblast – a stem cell Hematopoiesis • erythropoietin – controls rate of RBC formation – produced by kidneys in response to low blood oxygen Blood Types • ABO system – presence of surface antigens on the RBCs AND the antibodies in the plasma • antigen Blood Types – substance the body recognizes as foreign – stimulates immune response • antibodies – recognize antigens and binds to them Blood Types • agglutination – clumping of RBC due to antibodies binding antigens • antigens also called agglutinogens • antibodies called agglutinins Agglutination Rh blood groups • Rh antigens (Rhesus monkeys) • antibodies not automatically formed • if Rh- person receives Rh+ blood, they develop antibodies – hemolysis occurs the 2nd exposure • pregnant Rh- women – carrying Rh+ babies Lab • Blood Typing Crime Scene Investigation • groups of 3
