Blood PDF

Blood  Functions of Blood Transport of: – Gases, nutrients, waste products – Regulatory molecules Regulation of pH and osmosis Maintenance of body temperature Protection against foreign substances Clot formation Composition of Blood  Plasma...

Blood  Functions of Blood Transport of: – Gases, nutrients, waste products – Regulatory molecules Regulation of pH and osmosis Maintenance of body temperature Protection against foreign substances Clot formation Composition of Blood  Plasma Liquid part of blood – Pale yellow made up of 91% water, 9% other Colloid: Liquid containing suspended substances that don’t settle out – Albumin: Important in regulation of water movement between tissues and blood – Globulins: Immune system or transport molecules – Fibrinogen: Responsible for formation of blood clots  Formed Elements Red blood cells (erythrocytes) White blood cells (leukocytes) – Granulocytes Neutrophils Eosinophils Basophils – Agranulocytes Lymphocytes Monocytes Platelets (thrombocytes)  Production of Formed Elements Hematopoiesis or hemopoiesis: Process of blood cell production Stem cells: All formed elements derived from single population – Proerythroblasts: Develop into red blood cells – Myeloblasts: Develop into basophils, neutrophils, eosinophils – Lymphoblasts: Develop into lymphocytes – Monoblasts: Develop into monocytes – Megakaryoblasts: Develop into platelets Hematopoiesis Erythrocytes Structure – Biconcave, anucleate Components – Hemoglobin – Lipids, ATP, carbonic anhydrase Function – Transport oxygen from lungs to tissues and carbon dioxide from tissues to lungs 19-8  Hemoglobin Consists of: – 4 globin molecules: Transport carbon dioxide – 4 heme molecules: Transport oxygen Iron is required for oxygen transport 19-9  Erythropoiesis Production of red blood cells – Stem cells proerythroblasts early erythroblasts intermediate late reticulocytes Erythropoietin: Hormone to stimulate RBC production Hemoglobin Breakdown  Leukocytes Types – Neutrophils: Most common; phagocytic cells destroy bacteria (60%) Protect body against – Eosinophils: Detoxify chemicals; microorganisms and reduce inflammation (4%) remove dead cells and – Basophils: Alergic reactions; Release histamine, heparin increase debris inflammation response (1%) – Lymphocytes: Immunity 2 types; B & T Cell types – Monocytes: Become macrophages Leukocytes Thrombocytes Cell fragments pinched off from megakaryocytes in red bone marrow Important in preventing blood loss – Platelet plugs – Promoting formation and contraction of clots  Hemostasis Arrest of bleeding Events preventing excessive blood loss – Vascular spasm: Vasoconstriction of damaged blood vessels – Platelet plug formation – Coagulation or blood clotting Platelet Plug Formation Coagulation Stages – Activation of prothrombinase – Conversion of prothrombin to thrombin – Conversion of fibrinogen to fibrin  Blood Grouping Determined by antigens on surface of RBCs Antibodies (agglutinins) can bind to RBC antigens, resulting in aggregation (clumping) or hemolysis (rupture) of RBCs Groups – ABO and Rh ABO Blood Groups Agglutination Reaction Typing Blood – Single drops of blood are mixed with different antisera – Agglutination with an antisera indicates the presence of that antigen on the RBC  Rh Blood Group First studied in rhesus monkeys Types – Rh positive: Have these antigens present on surface of RBCs – Rh negative: Do not have these antigens present Hemolytic disease of the newborn (HDN) – Mother produces anti-Rh antibodies that cross placenta and cause agglutination and hemolysis of fetal RBCs Erythroblastosis Fetalis Diagnostic Blood Tests Type and crossmatch Complete blood count – Red blood count – Hemoglobin measurement – Hematocrit measurement White blood count Differential white blood count Clotting  Blood Disorders Erythrocytosis: RBC overabundance Anemia: Deficiency of hemoglobin – Iron-deficiency – Pernicious – Hemorrhagic – Hemolytic – Sickle-cell