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Platelets          PREPARED BY:MARIA CARMELA L. DOMOCMAT, RN, MSN
Platelets (Thrombocytes)o Platelets are not complete cells, but fragments of  large cells called megakaryocytes.o very sma...
o contains 2 types of granules   alpha (ά)granules    •   express P-selection on their surface:        contains fibrinogen...
o must be adequate in number and  function in order to participate  optimally in hemostasiso normally circulate as individ...
Functionso help to prevent or stop bleeding, a  process called hemostasiso Initiate contraction of damaged blood  vessels ...
Hematopoiesis: Blood Cell Formation
Formationbud off from megakaryocytes giant multinucleate bone marrow cells derived from the myeloid stem cell linestem cel...
o develop by endomitosis o   Formation of platelets involves repeated mitoses     of megakaryocytes without cytokinesis.  ...
Blood Components: PlateletsCoagulate, form plug, prevent blood lossFormed by fragmentation from megakaryoctyes            ...
o newly formed platelets that are  released from bone marrow spend up  to 8 hours in the spleen before  being released int...
Regulators Of Platelet Production includes:  •   GM-CSF (granulocyte-macrophage colony-      stimulating factor)  •   Thro...
Destruction (Hemolysis)o Senescent platelets – phagocytosed by neutrophils and monocytes if circulating freely   If part o...
Hemostasis
Hemostasis   Refers to the stoppage of bloodflow• Designed to maintain integrity of  vascular compartment• Normal •   when...
Control of hemostasiso Endothelium – major site of hemostasiso Despite the continual presence of  clotting factors and pla...
Three hemostatic compartments
Damage to small blood vessels and capillariesfrequently occurs. When these vessels are damaged,    there are 5 basic mecha...
5 stages of Hemostasis1.Vessel or vascular spasm -  (vasoconstriction at injured site)2.Formation of the platelet plug  (p...
5 stages of Hemostasis1.Vessel or vascular spasm(vasoconstriction at injured site)
(1) Blood Vessel Spasm•   triggered by pain receptors, platelet release, or serotonin•   smooth muscle in vessel contracts
5 stages of Hemostasis1.Vessel or vascular spasm2.Formation of the platelet plug (plugging the hole)
(2) Platelet Plug Formation•   triggered by exposure of platelets to collagen•   platelets adhere to rough surface to form...
Platelet Plug Formation                          14-28
Vasoconstriction & Plug Formation        Figure 16-12: Platelet plug formation
5 stages of Hemostasis1.vascular spasm2.platelet plug3.Blood coagulation or development of an insoluble fibrin clot (blood...
(3) Blood Coagulation•    triggered by cellular damage and blood contact with foreign    surfaces•    blood clot forms
ClotFormation & Vessel  Repair
Clot StabilizationProthrombinCa++FibrinogenFibrinPolymerization
Blood Coagulation                    14-29
Blood CoagulationExtrinsic Clotting Mechanism    • chemical outside of blood triggers blood coagulation    • triggered by ...
Blood Clots• After forming, blood clot retracts and pulls the edges of a broken vesseltogether• Platelet-derived growth fa...
5 stages of Hemostasis1.vascular spasm2.platelet plug3.Blood coagulation4.Clot retraction5.Clot dissolution
5 stages of Hemostasis1.vascular spasm2.platelet plug3.Blood coagulation4.Clot retraction5.Clot dissolution
Dissolving the Clot and AnticoagulantsBleeding stoppedVessel repairPlasminFibrinolysisClot dissolved
Dissolving the Clot and Anticoagulants         Figure 16-14: Coagulation and fibrinolysis
Prevention of Coagulation• The smooth lining of blood vessels discourages the accumulationof platelets• As a clot forms, f...
Coagulation and DiseaseHemophiliaCardiovascular Diseases Key problem – clots block undamaged blood vessels Anticoagulants ...
Factor                       Function                                                 Coagulation disorders in children In...
Laboratory tests
Peripheral blood smear
platelet countbleeding timePT (extrinsic pathway)activated thromboplastin time (intrinsic pathway),thrombin time
Disorders of Hemostasis
Two main categories of disorders         of hemostasis1. Inappropriate formation of clots   within the vascular system (i....
Impaired hemostasisVitamin K deficiencyLiver disease
Thromboembolic Disordersundesirable clottinga. thrombusb. embolus
Clotting Disorders  Coagulation disorders result from defects in the clotting cascade or fibrinolytic process. These disor...
Quantitative    platelet disordersa.Thrombocythemiab.Thrombocytopenia
Petechiae and purpura
Large ecchymosis
Thrombus / embolus
Embolus /embolism
Hemarthrosis
Melena         Hematuria
HematomaSubdural        Subungual
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)
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Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)

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Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets)

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Transcript of "Nursing Care of Clients with Hematologic Problems Part 2 of 2 : Thrombocytes (Platelets) "

  1. 1. Platelets PREPARED BY:MARIA CARMELA L. DOMOCMAT, RN, MSN
  2. 2. Platelets (Thrombocytes)o Platelets are not complete cells, but fragments of large cells called megakaryocytes.o very small, colorless cell fragments (2-4 microns in diameter)o enclosed in a membrane but have no nucleus and cannot reproduceo have mitochondria and enzyme system (enzyme – needed for synthesis of prostaglandin)
  3. 3. o contains 2 types of granules alpha (ά)granules • express P-selection on their surface: contains fibrinogen, fibronectin, factors V and VIII, platelet factor 4 (heparin-binding chemokine), platelet-derived growth factor (PDGF), transforming growth factor-alpha (TGF- ά) gamma (δ)granules or dense granules • contain ADP and ATP, ionized calcium, histamine, epinephrine
  4. 4. o must be adequate in number and function in order to participate optimally in hemostasiso normally circulate as individual cell-like structure, not attached to each other, suspended in plasma, and do not clump together until activated
  5. 5. Functionso help to prevent or stop bleeding, a process called hemostasiso Initiate contraction of damaged blood vessels to minimize blood losso Form hemostatic plugs in injured blood vessels to help stop bleedingo Along with plasma, they provide materials that accelerate blood clot formulation, or coagulation
  6. 6. Hematopoiesis: Blood Cell Formation
  7. 7. Formationbud off from megakaryocytes giant multinucleate bone marrow cells derived from the myeloid stem cell linestem cellHemotocytoblastMegakaryoblastPromegakaryocyte Megakaryocyte megakaryocyte: large multilobed nucleusplatelets platelets: anucleated parts of megakaryocyte cytoplasm
  8. 8. o develop by endomitosis o Formation of platelets involves repeated mitoses of megakaryocytes without cytokinesis. Megakaryocytes undergo mitosis but not cytokinesis thus cell does not divide into 2 daughter cells • Without cytokinesis – cell does not divide into 2 daughter cells but expands to accommodate the doubling of its DNA (nuclear) content and breaks up into fragments known as platelets
  9. 9. Blood Components: PlateletsCoagulate, form plug, prevent blood lossFormed by fragmentation from megakaryoctyes Figure 16-10c: Megakaryocytes and platelets
  10. 10. o newly formed platelets that are released from bone marrow spend up to 8 hours in the spleen before being released into the bloodo Life Span: 10 days
  11. 11. Regulators Of Platelet Production includes: • GM-CSF (granulocyte-macrophage colony- stimulating factor) • Thrombopoietin o source: kidney, liver, smooth muscle, bone marrow production and release is regulated by the number of platelets in circulation stimulate committed cells and further stages of differentiation
  12. 12. Destruction (Hemolysis)o Senescent platelets – phagocytosed by neutrophils and monocytes if circulating freely If part of thrombus or clot - phagocytosed by neutrophils and macrophage Can be removed also by tissue macrophages of the MPS (mononuclear phagocyte system) in the liver or spleen
  13. 13. Hemostasis
  14. 14. Hemostasis Refers to the stoppage of bloodflow• Designed to maintain integrity of vascular compartment• Normal • when it seals a blood vessel to prevent blood loss and hemorrhage• Abnormal • when it causes inappropriate blood clotting or when clotting is insufficient to stop the flow of blood from the vascular compartment
  15. 15. Control of hemostasiso Endothelium – major site of hemostasiso Despite the continual presence of clotting factors and platelets in circulation, blood normally remains fluido 2 properties of normal vascular endothelium prevent clotting Smooth texture of endothelial lining Negative charge of protein in endothelial cells – which repel some negatively charged platelets if clotting factors
  16. 16. Three hemostatic compartments
  17. 17. Damage to small blood vessels and capillariesfrequently occurs. When these vessels are damaged, there are 5 basic mechanisms that promote hemostasis or the stoppage of bleeding
  18. 18. 5 stages of Hemostasis1.Vessel or vascular spasm - (vasoconstriction at injured site)2.Formation of the platelet plug (plugging the hole)3.Blood coagulation or development of an insoluble fibrin clot (blood clotting - complex mechanism)4.Clot retraction5.Clot dissolution
  19. 19. 5 stages of Hemostasis1.Vessel or vascular spasm(vasoconstriction at injured site)
  20. 20. (1) Blood Vessel Spasm• triggered by pain receptors, platelet release, or serotonin• smooth muscle in vessel contracts
  21. 21. 5 stages of Hemostasis1.Vessel or vascular spasm2.Formation of the platelet plug (plugging the hole)
  22. 22. (2) Platelet Plug Formation• triggered by exposure of platelets to collagen• platelets adhere to rough surface to form a plug
  23. 23. Platelet Plug Formation 14-28
  24. 24. Vasoconstriction & Plug Formation Figure 16-12: Platelet plug formation
  25. 25. 5 stages of Hemostasis1.vascular spasm2.platelet plug3.Blood coagulation or development of an insoluble fibrin clot (blood clotting - complex mechanism)
  26. 26. (3) Blood Coagulation• triggered by cellular damage and blood contact with foreign surfaces• blood clot forms
  27. 27. ClotFormation & Vessel Repair
  28. 28. Clot StabilizationProthrombinCa++FibrinogenFibrinPolymerization
  29. 29. Blood Coagulation 14-29
  30. 30. Blood CoagulationExtrinsic Clotting Mechanism • chemical outside of blood triggers blood coagulation • triggered by thromboplastin (not found in blood) • triggered when blood contacts damaged tissueIntrinsic Clotting Mechanism • chemical inside blood triggers blood coagulation • triggered by Hageman factor (found inside blood) • triggered when blood contacts a foreign surface 14-30
  31. 31. Blood Clots• After forming, blood clot retracts and pulls the edges of a broken vesseltogether• Platelet-derived growth factor stimulates smooth muscle cells and fibroblaststo repair damaged blood vessels• Plasmin digests blood clots• thrombus – abnormal blood clot• embolus – blood clot moving through blood 14-31
  32. 32. 5 stages of Hemostasis1.vascular spasm2.platelet plug3.Blood coagulation4.Clot retraction5.Clot dissolution
  33. 33. 5 stages of Hemostasis1.vascular spasm2.platelet plug3.Blood coagulation4.Clot retraction5.Clot dissolution
  34. 34. Dissolving the Clot and AnticoagulantsBleeding stoppedVessel repairPlasminFibrinolysisClot dissolved
  35. 35. Dissolving the Clot and Anticoagulants Figure 16-14: Coagulation and fibrinolysis
  36. 36. Prevention of Coagulation• The smooth lining of blood vessels discourages the accumulationof platelets• As a clot forms, fibrin absorbs thrombin and prevents the reaction fromspreading• Antithrombin interferes with the action of excess thrombin• Some cells secrete heparin 14-32
  37. 37. Coagulation and DiseaseHemophiliaCardiovascular Diseases Key problem – clots block undamaged blood vessels Anticoagulants prevent coagulation Keep platelets from adhering Prevent fibrin coagulation "Clot Busters": Prevent further clotting Speed fibrinolysis Limit tissue damage (heart, brain…)
  38. 38. Factor Function Coagulation disorders in children IncidenceI: Fibrinogen Afibrinogenemia, 0.1 x 106 hypofibrinogenemiaII: Prothrombin Hypoprothrombinemia 0.1 x 106III: Tissue thromboplastinIV: Calcium divalent cation; a cofactor for most of the enzyme- activated processes required in blood coagulation; enhances platelet aggregation and makes RBCs clump togetherV: Proaccelerin Parahemophilia, Factor V 0.1 x 106 deficiencyVI: discovered to be an No factor VI is involved in coagulation -artifactVII: Proconvertin Factor VII deficiency 0.1 x 106VIII: Anithemophilic combined with von Willebrands factor help platelets Hemophilia A, von Willebrand 30-40 x 106 adhere to capillary walls in areas of tissue injury diseaseIX: Plasma thromboplastin essential in common pathway between intrinsic and Hemophilia B 3-4 x 106component (Christmas extrinsic clotting cascadesfactorX: Stuart-Power factor Factor X deficiency 0.1 x 106XI: Plasma thromboplastin Hemophilia C, PTA deficiency 0.1 x 106antecedent (PTA)XII Hageman factor critically important in intrinsic pathway Hageman trait 0.1 x 106XIII Fibrin-stabilizing assist in forming links among fibrin threads to form a Factor XIII deficiency 0.1 x 106factor strong fibrin clot
  39. 39. Laboratory tests
  40. 40. Peripheral blood smear
  41. 41. platelet countbleeding timePT (extrinsic pathway)activated thromboplastin time (intrinsic pathway),thrombin time
  42. 42. Disorders of Hemostasis
  43. 43. Two main categories of disorders of hemostasis1. Inappropriate formation of clots within the vascular system (i.e., thrombosis)2. Failure of blood to clot in response to an inappropriate stimulus (i.e., bleeding)
  44. 44. Impaired hemostasisVitamin K deficiencyLiver disease
  45. 45. Thromboembolic Disordersundesirable clottinga. thrombusb. embolus
  46. 46. Clotting Disorders Coagulation disorders result from defects in the clotting cascade or fibrinolytic process. These disorders may be inherited or acquireda. Hemophiliasb. Von Willebrand diseasec. Disseminated intravascular coagulation (DIC)
  47. 47. Quantitative platelet disordersa.Thrombocythemiab.Thrombocytopenia
  48. 48. Petechiae and purpura
  49. 49. Large ecchymosis
  50. 50. Thrombus / embolus
  51. 51. Embolus /embolism
  52. 52. Hemarthrosis
  53. 53. Melena Hematuria
  54. 54. HematomaSubdural Subungual
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