BSC 2086 1st Edition Lecture 8 Outline of Last Lecture I Components and Functions of Blood II Physical Characteristics of Blood III Plasma IV Blood Typing Outline of Current Lecture I Blood Typing Continued II White Blood Cells III Platelets IV Hemostasis Current Lecture I II Blood Typing Continued a Rh Factor i D antigen ii Two options Rh positive Rh or Rh negative Rh iii Anti Rh antibodies only found in sensitized Rh blood b Transfusions i Cross reactions aka Transfusion reaction 1 Plasma antibody meets its specific antigen 2 Blood agglutinates and hemolyzes 3 This happens when the donor and recipients blood types are NOT compatible ii Testing for compatibility 1 Performed on donor and recipient 2 Type O is universal donor if a cross match is not made a Cross match exposing donors RBCs to recipients plasma White Blood Cells a Structure i Aka leukocytes ii No hemoglobin iii Have nuclei and other organelles b Functions i Part of immune system therefore defend against pathogens ii Remove wastes and toxins iii Attack foreign or abnormal cells c Circulation and Movement i Found in connective tissue as well as in lymphatic system organs ii Small amount found in blood iii Can migrate out of bloodstream 1 Some types of capillaries have gaps to allow cells to leave iv Amoeboid movement 1 Allows them to squeeze into little gaps in capillaries v Drawn to chemical stimuli 1 Positive chemotaxis 2 Positive presence of these chemicals will attract WBCs into the area vi Some are phahocytic neutrophils eosinophils monocytes d Types i Neutrophils granulocytes 1 Aka polymorphonuclear leukocytes 2 Pale cytoplasm granules with lysosomal enzymes and bactericides 3 50 70 of WBCs that are circulating 4 Action a First attackers of bacteria very active b Phagocytic engulf and digest pathogens c Degranulation involves removal of granules from cytoplasm lysosome fuses to endosome i Peptides from lysosomes known as defensins attack the membranes of the pathogens d Release prostaglandins and leukotrienes i Increases inflammation and attracts other phagocytes e Form pus i Made of dead neutrophils cellular debris and wastes ii Eosinophils Acidophils granulocytes 1 2 4 of WBCs that are circulating 2 Attack large parasites and excrete toxins nitric oxide and cytotoxic enzymes 3 Sensitive to allergens a Increases during allergic reactions 4 Use enzymes that oppose the inflammatory effects of neutrophils and mast cells in order to control or reduce inflammation iii Basophils granulocytes 1 Less than 1 of circulating WBCs 2 Accumulate in damaged tissue 3 Release histamine to dilate blood vessels and heparin to prevent blood clotting iv Monocytes agranulocytes 1 2 8 of circulating WBCs 2 Very large and spherical III 3 Become macrophages when entering peripheral tissues 4 Phagocytic 5 Secrete special substance that attracts immune system cells and fibrocytes to the area injured v Lymphocytes agranulocytes 1 20 30 of circulating WBCs 2 Larger than RBCs therefore able to migrate in and out of blood 3 Found in connective tissues and lymphoid organs 4 Part of bodies defense system 5 Three classes a T cells i Cell mediated immunity ii Directly attack foreign cells b B cells i Humoral immunity ii Become plasma cells and synthesize antibodies c Natural killer NK cells i Detects and destroy abnormal tissue cells 1 Cancer e Differential Count i Detects changes in WBC amounts due to infections inflammation and allergic reactions f Disorders i Leukopenia abnormally low count ii Leukocytosis abnormally high count iii Leukemia extremely high count g Production i All blood cells come from hemocytoblasts 1 Produce progenitor cells myeloid stem cells and lymphoid stem cells 2 Myeloid stem cells produce all types except lymphocytes 3 Lymphoid stem cells make lymphocytes through lymphopoiesis ii All except monocytes develop in bone marrow iii Monocytes develop into macrophages in peripheral tissues 1 Start developing in red bone marrow but enter bloodstream before completion Platelets a Structure i Cell fragments ii Involved in clotting iii Thrombocytes type found in nonmammalian vertebrates nucleated cells iv Circulate for 9 12 days and removed by spleen v 2 3 are kept on reserve for emergencies IV b Counts i Thrombocytopenia abnormally low count ii Thrombocytosis abnormally high count c Functions i Release important chemicals necessary for clotting ii Patch damaged blood vessel walls temporarily iii Reduce the size of a break in a blood vessel d Production i Thrombocytopoiesis in bone marrow 1 Megakaryocytes giant cells that manufacture platelets from cytoplasm a Develop from myeloid stem cells Hemostasis a Definition cessation of bleeding b Three phases i Vascular Phase 1 A 30 minute vascular spasm occurs after a cut 2 Three steps a Endothelial cells contract and uncover basement membrane to the bloodstream b Endothelial cells will release ADP tissue factor and prostacyclin chemicals i Release endothelins local hormones ii Stimulate smooth muscle contraction and cell division 1 Smooth muscle contraction will squeeze and cause blood vessel to constrict so you don t lose a lot of blood 2 Cell division to make up for a part that s damaged c Plasma membranes of endothelial cells becomes sticky and seal off blood flow ii Platelet Phase 1 Starts 15 seconds after injury 2 Platelet adhesion or attachment to a Sticky endothelial surfaces b Basement membranes c Exposed collagen fibers 3 Platelet aggregation or stick together a Platelet plug forms when platelets are activated and stick to other platelets b Closes small breaks c When platelets are activated they form i Adenosine triphosphate ADP excites platelet secretion and aggregation ii Thromboxane A2 and serotonin both cause vascular spasms iii Clotting factors iv Platelet derived growth factor PDGF promotes repair of vessels v Calcium ions d Platelet plug growth is limited by i Prostacyclin inhibits platelet aggregation ii Inhibitors made by other WBCs iii Circulatory enzymes that break down ADP iv Negative feed back from serotonin that inhibits and blocks the action of ADP v Development of blood clot isolates the area iii Coagulation Phase 1 Formation of fibrin 2 Begins 30 seconds or more after the injury 3 Coagulation blood clotting 4 Cascade reactions are chain reactions of enzymes and proenzymes a Make 3 pathways b Convert circulating fibrinogen into insoluble fibrin c Clotting factors i Aka procoagulants ii Proteins ions in plasma including Ca2 iii Needed for normal clotting iv
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