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59 Cards in this Set
- Front
- Back
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Hemostasis consits of a series of reactions which act to do what?
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Stop bleeding
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What are the 3 phases that occur in rapid sequence in hemostasis?
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Vascular spasms, platelet plug formation, and coagulation.
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What is the immediate vasoconstriction in response to injury called?
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Vascular spasms
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Blood cotting and fibrin clot formation are examples of what?
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Coagulation
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List what occurs in response to tissue injury.
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Vascular spasm
Platelet plug formation Blood clot formation – coagulation Clot retraction Fibrinolysis Reorganization Repair and regeneration |
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Vascular spasm can also be called...
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vasospasm or vasoconstriction
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T/F
Vascular spasm is spontaneous. |
True!
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Vascular spasm is (immediate/delayed) and (temporary/long-lasting).
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Immediate, temporary
It lasts for a maximum of 30 minutes. |
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Vascular spasm can be triggered by what 3 things?
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Direct injury to vascular smooth muscle
Chemicals released by endothelial cells and platelets Initiated/maintained/ by local pain receptors |
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Spasm mechanism becomes (less/more) efficient as the amount of tissue damage increases.
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More
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Spasm is most effective in (small/large) vessels.
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Small
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What does blood need to be exposed to in order to initiate platelet plug formation?
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Damaged endothelium, underyling collagen
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What are the 5 steps in platelet plug formation?
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1. Activation
2. Adhesion 3. Aggregation 4. Cohesion 5. Temporary and permanent plug |
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What is the KEY step in blood clotting?
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The conversion of fibrinogen to fibrin by thrombin.
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What are the 3 basic steps of blood coagulation?
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1. Formation of PROTHROMBIN ACTIVATOR
2. Formation of THROMBIN 3. Conversion of Fibrinogen to Fibrin |
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Rupture of a vessel and damage of endothelium will cause what to begin?
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Activation of prothrombin activator (PA).
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Prothrombin activator (PA) can be formed by (extrinsic/intrinsic) pathways.
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Trick question!
It can be formed by either extrinsic or intrinsic pathways |
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What is PA's main function?
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Activates prothrombin (go figure)
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PA catalyzes what reaction?
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Conversion of prothrombin to thrombin
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What factors form prothrombin activator?
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activated factor X
factor V Phospholipids Ca2+ |
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What is the intrinsic (vascular) pathway for the formation of PA initiated by?
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Surface contact (contact activation): coming in contact with an activated platelet.
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What is the extrinsic (extravascular) pathway for the formation of PA initiated by?
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Tissue factor activation: initiated by tissues outside the vascular system.
Each pathway cascades toward factor X |
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Which formation of PA pathway is triggered by the exposure of collagens in the vascular wall to factor XII and thrombocytes?
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Intrinsic pathway
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Which formation of PA pathway is slow to proceed and can take 2-6 minutes?
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Intrinsic pathway
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Which formation of PA pathway has many inhibitory or antagonistic mechanisms that exist in the blood?
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Intrinsic pathway
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Which formation of PA pathway is triggered by tissue trauma?
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Extrinsic pathway
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Which formation of PA pathway is explosive in nature and can be completed in 15 seconds?
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Extrinsic pathway
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Which formation of PA pathway has no inhibitory mechanisms counteracting it?
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Extrinsic pathway
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What acts as the catalyst to convert the plasma protein fibrinogen to soluble fibrin?
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Thrombin
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How do fibrin threads lead to coagulation?
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These fibrin threads form a meshwork, so blood cells get entangled in it to form the clot or coagulum.
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What is needed to activate factor XIII?
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Thrombin and Ca2+
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What do factor XIII(activated) and Ca2+ do together?
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Convert fibrin monomer (soluble) to polymer (insoluble).
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Why is factor XIII a fibrin stabilizing factor?
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Cross-links fibrin
Strengthens and stabilizes the clot (polymer, insoluble) |
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How do clots retract?
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Actin and myosin in the fibrin mesh platelets retract ("contract") and serum is extruded from the fibrin mesh. This causes the clot to retract.
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During repair of the vascular wall, what stimulates rebuilding of the blood vessel wall?
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Platelet-derived growth factor (PDGF)
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In repair of the vascular wall, what do fibroblasts form?
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A connective tissue patch
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In repair of the vascular wall, endothelial cells multiply and restore the endothelial lining. What stimulates this?
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Vascular endothelial growth factor (VEGF)
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Name the inactive precursor of the proteolytic enzyme plasmin. It is present in normal blood.
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Plasminogen
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What activates the conversion of plasminogen to plasmin (or fibrinolysin)?
Where are they found? |
Tissue plasminogen activators (tPA).
In tissues, plasma, and urine |
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T/F
There are physiological mechanisms that cause the clots to form at the site where a blood vessel is injured but keep the vessel lumen free of clots. |
True!
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Interaction between the platelet-aggregating factors (thromboxane A2) and anti-aggregating factor (prostacyclin) are part of what mechanisms?
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Anticlotting mechanisms
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Name the circulating protease inhibitor that binds to serine proteases in the coagulation system, blocking their activity as clotting factors.
What is this reaction facilitated by? |
Antithrombin III
Heparin |
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Name the thrombin-binding protein that endothelial cells produce.
When thrombin binds this protein, it becomes what? |
Thrombomodulin
Anticoagulant |
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What complex activates the fibrinolytic system (plasminogen-plasmin system)?
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Thrombomodulin-thrombin complex
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Intact, smooth, functional endothelium is an example of an (in vivo/in vitro) anticoagulant.
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In vivo
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Heparin is an example of an (in vitro/in vivo) anticoagulant.
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Both!
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[Thrombin + thrombomodulin] is an example of an (in vitro/in vivo) anticoagulant.
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In vivo
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Prostacyclin is an example of an (in vitro/in vivo) anticoagulant.
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In vivo
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[Thromboxane A2+prostacyclin] is an example of an (in vitro/in vivo) anticoagulant.
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In vivo
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Antithrombin III is an example of an (in vitro/in vivo) anticoagulant.
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In vivo
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Thrombomodulin is an example of an (in vitro/in vivo) anticoagulant.
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In vivo
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The plasminogen system (fibrinolysins) is an example of an (in vitro/in vivo) anticoagulant.
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In vivo
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Vitamin K antagonists (inhibit activity of VII, IX, and X), such as Dicumarol, Warfavin, and Diphenadlone, are examples of (in vitro/in vivo) anticoagulants.
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In vitro
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Calcium chelators, such as sodium citrate and ethylene diamine tetraacetic acid (EDTA), are examples of (in vitro/in vivo) anticoagulants.
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In vitro
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What are three types of clotting abnormalities?
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Hemorrhagic diseases (bleeding disorders)
Thrombosis: Thrombi and emboli Disseminated intravascular coagulation (thrombi and bleeding) |
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Which clotting abnormality is due to deficiencies of the clotting factors (Hemophilia A- factor VIII deficiency)?
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Hemorrhagic diseases (bleeding disorders)
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Which clotting abnormality is due to uncontrolled intravascular coagulation?
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Thrombosis: Thrombi and emboli
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Which clotting abnormality is due to the consumption of platelets and increased coagulation factors and excessive thrombi formation in many small- and medium-sized vessels (and bleeding at the same time)?
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Disseminated intravascular coagulation (thrombi and bleeding)
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What are 2 platelets disorders (bleeding disorders)?
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Thrombocytopenia (low number of platelets)
Thrombasthenia (low function of platelets) |
