Term
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Definition
| the property of the circulation that maintains blood as a fluid within the blood vessels and the system's ability to prevent excessive blood loss upon injury |
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Term
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Definition
| "clotting"- the mechanism that transforms the fluid plasma into a gel by converting the soluble protein fibrinogen to the insoluble form, fibrin. |
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Term
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Definition
| is the formation of a blood clot or thrombus, usually considered to be under abnormal conditions within a blood vessel |
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Term
| Blood vessels role in maintaining hemostasis |
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Definition
| initiate hemostasis by vasoconstriction (of arterioles) to minimize blood flow to wound area, and to bring hemostatic components of the blood closer to the vessel wall |
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Term
| Systems involved in maintaining hemostasis |
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Definition
| blood vessels, the platelets and the plasma proteins |
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Term
| Platelets role in maintaining hemostasis |
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Definition
| perform surveillance of blood vessels for gaps, they maintain vessels continuity by filling those gaps, and they attach to exposed collagen to prevent blood from escaping |
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Term
| Plasma proteins role in maintaining hemostasis |
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Definition
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Term
| Events that occur in primary hemostasis |
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Definition
| reaction of blood vessels to injury, damaged endothelial cells release endothelin, which causes vasoconstriction. The platelet plug begins to form, first platelets adhere to collagen, and then platelets are activation and release ADP, thromboxane A2, and serotonin, which recruits additional platelets. The platelets aggregate to form a hemostatic plug. |
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Term
| Events that occur in secondary hemostasis |
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Definition
| formation of fibrin to reinforce the platelet plug |
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Term
| What is the primary hemostatic plug? |
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Definition
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Term
| What is the secondary hemostatic plug? |
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Definition
| the platelets held together by fibrin deposits |
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Term
| What are the three types of blood vessels? |
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Definition
| arterioles, venules, and capillaries |
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Term
| General roles of the vasculature |
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Definition
| regulate blood pressure by change in diameter |
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Term
| General roles of normal endothelial cells |
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Definition
| activate coagulation factors |
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Term
| Role of vasculature in aiding and preventing activation of the hemostatic system |
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Definition
| vasculature constriction in order to limit the amount of blood to the wound and to allow the hemostatic components to get closer to the wound. |
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Term
| Role of endothelial cells in aiding and preventing activation of the hemostatic system |
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Definition
| Damaged endothelium becomes thrombogenic, producing substances that activate platelets and coagulation proteins and inhibit fibrinolysis |
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Term
| Normal morphology of platelets on a peripheral blood smear |
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Definition
| Platelets appear on a Romanowsky-stained peripheral blood smear as small, anuclear cells with prominent reddish purple granules. They circulate as discoid-shaped structures, approximately 2-3 μm in diameter and have a lifespan of 9-12 days |
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Term
| Normal concentration of platelets in the blood |
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Definition
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Term
| Name and describe the cell that is the precursor of platelets in the bone marrow |
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Definition
| megakaryocyte- It is usually 20-60 μm in diameter, and has abundant pinkish, granular cytoplasm. There is a multi-lobated nucleus but no visible nucleoli. |
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Term
| Identify the steps in the normal sequence of events of platelet activation following injury to the endothelium |
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Definition
| resting, partially activated, and fully activated |
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Term
| Describe resting platelets |
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Definition
| disc shaped platelets circulating in the blood |
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Term
| Describe partially activated platelets |
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Definition
| beginning to change shape |
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Term
| Describe fully activated platelets |
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Definition
| changes in membrane shape, biochemistry, receptors and membrane phospholipid orientation |
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Term
| Describe the role of the primary hemostatic plug in the cessation of bleeding |
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Definition
| arrests bleeding by sticking first to exposed collagen and other components of the subendothelium and then to each other, the platelets form a mass that mechanically fills openings in the vessels and limits the loss of blood from the injury site. |
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Term
| Key histologic features of arteries |
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Definition
| inner most layer is thicker than in veins (tunica intima) consists of the endothelial cell monolater, the basement membrane and subendothelial connective tissue, also have an organized internal elastic membrane, smooth muslce cells predominate and are surround by loose connective tissue primary consisting of elastin fibers, colalgen fibers, reticular fibers, and proteoglycans, thinner outer coat (tunica adventita) |
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Term
| Key histologic features of veins |
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Definition
| inner most layer is thinner than in arteries (tunica intima) consists of the endothelial cell monolater, the basement membrane and subendothelial connective tissue, tunica media contains a few smooth muscle cells, fewer elastin fibers, and a similiar matrix of conective tissue, thicker outer coat (tunica adventita) |
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Term
| Key histologic features of capillaries |
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Definition
| 5-10uM in diameter, single endotherlial cells form the lumen with cytoplasm wrapped around, gap junctions, tissue beneath basement membrane is sparse and contains no smooth muscle cells |
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Term
| metabolic functions of endothelial cells in hemostasis |
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Definition
| secretes substances that (1) activate platelets (PAF) and bind them to the vessel wall (VWF) (2) activate coagulation (TF --> formation of fibrin) and (3) inhibit fibrinolysis (PAI-1) |
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Term
| Action of humoral factors in development of megakaryocytes |
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Definition
| TPO influences all stages of megakaryocyte production, it is produced in the liver, kidney and spleen. It maintains a constant number of platelets in the peripheral blood. TPO binds to platelets, megakaryocytes, and progenitors. When it binds to platelets it is not used, and is removed from circulation (therefore the high platelets counts = low TPO). There is not a lot of TPO left to stimulate megakaryocytes, but that’s okay because there is enough platelets. When platelets levels drop, more TPO is available to bind to megakaryocytes, which increases the production of platelets. |
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Term
| Action of stem cell compartment in development of megakaryocytes |
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Definition
| cycling of cells, endomitosis (nuclear cell divisions, maturation) begins |
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Term
| Action of progenitor cell compartment in development of megakaryocytes |
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Definition
| progenitor cells expand the megakaryocyte population in response to hematopoietic cytokines. They are indistinguishable from lymphoid-like cells. |
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Term
| Recognizable features of the morphologic stages of megakaryocyte development |
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Definition
| : The progenitor cell is indistinguishable from the lymphoid-like cells, the morphologically identifiable platelet precursor is a megakaryocyte. Precursor cell begins endomitosis ( DNA doubling without nuclear division). The 8N stage is recognizable because the megakaryocytes are becoming larger than other cells in bone marrow. Cytoplasmic maturation occurs at the 8N stage. |
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Term
| mechanism of release from the marrow to peripheral blood of the megakayocyte |
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Definition
| megakaryocytes shed proplatelets from the bone marrow into the sinuses, which break up into platelets. Sometimes mature megakaryocytes are released from the marrow and circulate and they become trapped in capillaries. |
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Term
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Definition
| 6-24 μm, scant basophilia, no visible granules, round nucleus with viable nucleoi |
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Term
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Definition
| 14-30 μm, basophilia, few visible granules, demarcation members |
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Term
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Definition
| 24-50 μm, granules, acidophilic cytoplasm, large, multi-lobulated nucleus, no nucleoli |
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Term
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Definition
| 40-60 μm, abundant acidophilic and granular cytoplasm, demarcation zones present, mutlilobulated nucleus, and no viable nucleoli |
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Term
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Definition
| rounds of nuclear DNA synthesis without nuclear or cytoplasmic division. |
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Term
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Definition
| when the number of chromosomes per cell that is a multiple of n (23) other than 1 or 2 (e.g., 3n[69], 4n[92]). |
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Term
| three key substances that are stored in the platelet dense bodies |
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Definition
| ADP (ATP), calcium ions (high concentration makes them “dense”), and serotonin. |
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Term
| Five key substances that are stored in the platelet alpha granules |
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Definition
| vWF, fibrinogen, platelet derived growth factor, platelet factor 4, and factor V and VIII |
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Term
| Role of ADP in hemostasis |
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Definition
| nonmetabolic, agonist for platelets |
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Term
| Role of ATP in hemostasis |
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Definition
| nonmetabolic, agonist for cells other than platelets; activates Ca2+ influx channel in outer membrane |
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Term
| Role of calcium ions in hemostasis |
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Definition
|
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Term
| role of serotonin in hemostasis |
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Definition
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Term
| role of vWF in hemostasis |
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Definition
| platelet adhesion, carries F-VIII in plasma |
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Term
| role of fibrinogen in hemostasis |
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Definition
| platelet aggregation, conversion to fibrin |
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Term
| role of platelet derived growth factor in hemostasis |
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Definition
| promotes regrowth of smooth muscle cells (wound repair) |
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Term
| role of platelet factor 4 in hemostasis |
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Definition
| neutralized heparin, weak neutrophil and fibroblast chemoattractant |
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Term
| role of factor V and VIII in hemostasis |
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Definition
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Term
| steps that platelets undergo in forming the primary hemostatic plug |
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Definition
| platelet adhesion, shape change, platelet aggregation, secretion, and formation of the primary plug |
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Term
| biochemical mediators necessary for platelet adhesion |
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Definition
| vWF, GPIb receptor site and PAF |
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Term
| biochemical mediators necessary for shape change |
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Definition
| agonist, GPIIb receptor appear |
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Term
| biochemical mediators necessary for secretion |
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Definition
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Term
| biochemical mediators necessary for formation of the primary plug |
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Definition
| TF initiates formation of fibrin |
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Term
| Platelet Peripheral zone function |
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Definition
| adhesion and aggretation, asymmetric arragement, source of arachidonic acid (phospholipid bilayer) |
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Term
| Platelet structural zone function |
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Definition
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Term
| Platelet organelle zone function |
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Definition
| secretion and storage, nonprotein mediators (ADP, ATP and serotonin), protein mediators, enzymes, lipid metabolism and oxidative energy metabolism |
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Term
| Platelet membrane systems function |
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Definition
| secretion and storage, secretion of granules contents and storage of calcium ions |
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Term
| Identify platelet agonists |
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Definition
| arachadonic acid, thromboxane A2, collagen, thrombin, ADP, and epinephrine |
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Term
| Arachadonic acid effects on platelet function |
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Definition
| initaite platlet activation but require platelet synthesis and release of endogenous TXA2 to drive full activation through secretion and aggregation |
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Term
| Thromboxane A2 effects on platelet function |
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Definition
| initaite platlet activation but require platelet synthesis and release of endogenous TXA2 to drive full activation through secretion and aggregation |
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Term
| Collagen effects on platelet function |
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Definition
| can activate the full range of platelet functions themselves |
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Term
| thrombin effects on platelet function |
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Definition
| can activate the full range of platelet functions themselves |
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Term
| ADP effects on platelet function |
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Definition
| initaite platlet activation but require platelet synthesis and release of endogenous TXA2 to drive full activation through secretion and aggregation |
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Term
| Epinephrine effects on platelet function |
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Definition
| initaite platlet activation but require platelet synthesis and release of endogenous TXA2 to drive full activation through secretion and aggregation |
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Term
| biochemical roles of the secreted contents of the platelet granules in hemostasis |
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Definition
| Secretion provides positive feedback in platelet activation, which ensures adequate hemostatic response. Some substances function as agonists; also they recruit additional layers of platelets and form the platelet plug |
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Term
| Correlate activation with changes in the platelet ultrastructure and biochemistry. |
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Definition
| Platelets becomes activated after agonists bind to the receptors on the platelet surface, initiating signaling events, which lead to reorganization of cytoskeleton, secretion and aggregation. |
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Term
| G proteins and activation |
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Definition
| agonists and receptors are linked to G proteins, which at as molecular switches to transmit signal to the cell |
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Term
| Phospholipase C and the phosphoinositide pathway and activation |
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Definition
| cleave phosphatidyl inositol biphosphate (PIP2) into Ip3 and DAG. These products mobilize calcium ions from storage and activate kinase enzymes |
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Term
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Definition
| assembly of contractile mechanisms responsible for platelet shape |
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Term
| Arachidonate pathway and activation |
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Definition
| phospholipase A2 hydrolyzes arachidonic acid from glycerol backbone of phospholipids. AA serves as a precursor for regulatory substances |
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Term
| cAMP pathway and activation |
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Definition
| negative regulatory of platelet activation, inhibits shape change, platelet secretion and integrin active. |
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Term
| Describe the roles of the platelet in secondary hemostasis |
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Definition
| Platelet activation leads to thrombin formation via coagulation factors binding to the surface of activated platelets. Fibrin forms amid and around the aggregated platelets, enhancing the plug. |
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Term
| Identify the life span of platelets in the peripheral blood |
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Definition
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Term
| The definition of hemostasis is |
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Definition
| termination of bleeding following a traumatic injury |
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Term
| What is the primary element that prevents blood from clotting inside blood vessels? |
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Definition
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Term
| What bone marrow cell is the precursor of platelets? |
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Definition
|
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Term
| what is the action of blood vessels in hemostasis? |
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Definition
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Term
| What happens when a cut finger initially stops bleeding |
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Definition
| formation of the primary hemostatic plug by aggregated platelets |
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Term
| What is a reasonable reference range for platelets in the peripheral blood? |
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Definition
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Term
| What is the first step in platelet function after an injury? |
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Definition
| platelet adhesion to collagen |
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Term
| What is the process called when platelets bind to one another |
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Definition
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Term
| What best describes the normal morphology of platelets on peripheral blood smear |
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Definition
| they are filled with azurophilic granules |
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Term
| What is involved in hemostasis |
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Definition
| vasocontriction by the blood vessels, adhesion and aggregation by platelets, fibrin formation by proteins in the plasma and platelets |
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Term
| What is NOT involved in hemostasis |
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Definition
| regulation of blood pressure |
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Term
| When a blood clot forms inappropriately inside a blood vessel, the process is called |
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Definition
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Term
| Which of the following processes is not an element of primary hemostasis? |
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Definition
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Term
| The primary hemostatic plug consists of |
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Definition
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Term
| When comparing the size of normal platelets to the size of normal erythrocytes on a Wright’s-stained peripheral blood smear |
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Definition
| Platelets are approximately one-third the diameter of the erythrocytes. |
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Term
| Which of the following is within a reasonable reference range for platelets? |
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Definition
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Term
| Vasoconstriction is a function of |
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Definition
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Term
| Platelet aggregation is the process of |
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Definition
| platelets binding to one another |
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Term
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Definition
| precursor cells to platelets in the bone marrow |
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Term
| The primary hemostatic plug is: |
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Definition
| the clump of platelets that forms during primary hemostasis |
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Term
| The events that occur in forming the primary hemostatic plug are |
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Definition
| platelet adhesion, aggregation, secretion |
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Term
| Which of the following is a thrombogenic substance produced by the endothelial cells? |
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Definition
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Term
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Definition
| DNA synthesis within a cell without accompanying cell or nuclear division |
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Term
| The parent compound from which thromboxane A2 is formed in the activated platelet is: |
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Definition
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Term
| What will occur if the synthesis of thromboxane A2 in the activated platelet is blocked? |
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Definition
| The platelet will be unable to secrete the contents of the granules. |
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Term
| One effect of ADP released from the granules of the activated platelet is feedback activation, which results in: |
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Definition
| appearance of the glycoprotein IIb/IIIa receptors |
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Term
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Definition
| a substance that activates platelets |
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Term
| Von Willebrand factor is stored in the platelet: |
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Definition
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Term
| Which of the following are platelet agonists? |
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Definition
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Term
| Platelet membrane phospholipases are activated by: |
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Definition
| agonist stimulation of a platelet membrane receptor |
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Term
| Lack of the GPIb/IX platelet receptor will result in: |
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Definition
| abnormal platelet adhesion to collagen |
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Term
| What prevents immediate bleeding? |
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Definition
| vasoconstriction of the blood vessels |
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Term
| What actions of the endothelial cells prevent clotting from occurring within the blood vessels? |
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Definition
| their negatively charged surface repeals clotting factors and platelets in the normal peripheral blood circulation. They synthesize heparin sulfate and thrombomodulin, which inhibit fibrin formation. They synthesize PGI2, which inhibits platelet activation. They synthesize tPA and PAI-1 which control fibrinolysis |
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Term
| What would be the effect on platelet count in a patient had a mutation in the gene for thrombopoietin that resulted in the gene's inability to code for functional mRNA? |
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Definition
| the platelet count would be decreased |
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Term
| If a patient has a mutation in a gene for TPO that resulted in the inability to code for mRNA, how would you expect the number of megakaryocytes on bone marrow smears to be affected? |
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Definition
| the number of megakaryocytes in the bone marrow would be decreased |
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Term
| If a patient inherited a mutation of the gene for glycoprotein IIIa that resulted in its absence, what two platelet antigens would be decreased or absent? |
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Definition
| the HPA-1 and HPA-3 would be decreased or absent |
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Term
| If a patient with Bernard-Soulier disease or VWD cut a finger, would you expect bleeding to stop as fast as the bleeding stops when you cut your own finger? Why or Why not? |
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Definition
| no, because their platelets would be unable to adhere to collagen and the primary hemostatic plug would take loner to form to halt the bleeding |
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Term
| To what do platelets first adhere to? |
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Definition
|
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Term
| what bridge and what platelet membrane receptor are needed for platelet adhesion? |
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Definition
|
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Term
| what bridge and what platelet membrane receptor are needed for platelets to attach to one another? |
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Definition
|
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Term
| What is the attachment of platelets to one another called? |
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Definition
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Term
| Outline the steps of primary hemostasis that have occurred after bleeding has ceased |
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Definition
| blood vessels have undergone vasocontriction and are by now possibly beginning to dilate. Platelet adhesion, platelet secretion, platelet aggregation, and formation of the primary hemostatic plug |
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