What is another name for the extrinsic pathway?
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Tissue activation/activator pathway.
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What is another name for the extrinsic pathway?
Tissue activation/activator pathway.
What triggers the contraction of smooth muscle in a blood vessel?
Trauma to the vessel wall.
What happens during platelet activation?
Conformational change occurs, leading to the release of granule contents and thromboxane A2 formation.
What is the significance of blood coagulation tests?
They help assess the functionality of the coagulation system and identify disorders.
What is the normal range for Prothrombin Time (PT)?
12 seconds.
What initiates the cascade of reactions in the extrinsic pathway?
Factors outside the vascular system.
What is the function of Prostacyclin?
Promotes vasodilation and inhibits platelet activation and clotting.
What are the general steps involved in hemostasis?
Vascular constriction, formation of platelet plug, formation of blood clot, growth of fibrous tissue.
What is the function of vascular spasm in hemostasis?
The smooth muscle in the vessel wall contracts near the injury point, reducing blood loss.
What role does Thromboxane A2 play in hemostasis?
It acts as a vasoconstrictor and activates more platelets.
How do signaling molecules affect platelet aggregation?
They amplify the platelet activation response and promote aggregation.
How does glycocalyx help prevent clotting?
It helps to prevent platelet adhesion to damaged surfaces.
What is tissue factor (factor III) and its role?
It is an integral membrane protein that serves as a receptor for factor VII.
What initiates the extrinsic pathway of coagulation?
Tissue injury, which releases tissue factor (factor III).
What is the significance of Vitamin K in coagulation?
It is essential for the synthesis of factors II, VII, IX, X, and Protein C.
What stabilizes fibrin strands?
Factor XIII.
What role does HMW kininogen play in the intrinsic pathway?
It acts as a cofactor, helping anchor Factor XII to the surface.
What is the role of Vitamin K in coagulation?
It is an essential cofactor for the formation of several clotting factors.
What is the role of vascular constriction in hemostasis?
It is the first mechanism that occurs to prevent blood loss.
What does Factor XIIa transform prekallikrein into?
Kallikrein, which acts as a protease.
What does a low INR value indicate?
A higher chance of having a clot.
What activates platelets in the hemostasis process?
vWF released by activated platelets binds to platelet receptor GPIb/Ia, activating more platelets.
What complex forms prothrombin activator?
Factor Xa + Phospholipid + Factor V.
What is the role of thrombin in coagulation?
It converts fibrinogen into fibrin monomers.
What is the normal range of platelet count in blood?
150,000 to 300,000 per microliter (μl).
What is thrombocytopenia?
A condition characterized by low blood platelet count.
What is the normal range for bleeding time?
1 to 6 minutes.
What occurs during the injury phase of hemostasis?
A blood vessel is severed, causing blood and components to leak out.
What is the formation of a platelet plug?
The process where platelets aggregate at the site of injury to stop bleeding.
What does Prothrombin Time (PT) measure?
The concentration of prothrombin in the blood and the time required for coagulation.
What is the role of anticoagulants in the body?
Anticoagulants oppose or limit coagulation to restore the clot-free condition of the blood.
What does a high INR value indicate?
A high risk of bleeding.
What is the role of glycoproteins in platelet membranes?
They prevent platelets from adhering to endothelium under normal conditions and facilitate adhesion to injured vessels.
What is the function of Nitric Oxide in hemostasis?
Inhibits platelet adhesion and aggregation.
What does prothrombin activator convert prothrombin into?
Thrombin.
What is Hemophilia A caused by?
Factor VIII (Antihemophilic Factor) deficiency.
How quickly does a clot develop after severe trauma?
In 15 to 20 seconds.
What is the primary function of hemostasis?
Prevention of blood loss or hemorrhage.
How are platelets activated during platelet plug formation?
By chemicals released from the injury site and contact with underlying collagen.
What is the role of anticoagulants in hemostasis?
They help maintain blood flow by preventing excessive clotting.
What mediates the adhesion of platelets during hemostasis?
Integrins platelet receptor and von Willebrand Factor (vWF).
What role does kallikrein play in the coagulation process?
It enhances the conversion of Factor XII into XIIa through positive feedback.
What clinical examples are associated with disorders of hemostasis?
Various conditions that affect normal blood clotting and bleeding.
What are the two main parts of hemostasis?
Primary hemostasis and Secondary hemostasis.
What does Antithrombin III do?
Binds to and inhibits Factor Xa and thrombin.
Which factors are involved in the intrinsic pathway?
Factors XII, XI, VIII, Prekallikrein, HMW kininogen, Ca²⁺, and phosphatidylserine.
Which vitamin is essential for blood clotting?
Vitamin K.
What happens to the coagulation cascade when plasmin is active?
It stops the coagulation cascade as the clot is ready to be degraded.
What does a prolonged bleeding time indicate?
It indicates a lack of platelets or issues with platelet function.
What are the pathways involved in the coagulation cascade?
Extrinsic pathway, intrinsic pathway, and common pathway.
What factors are involved in the coagulation pathways?
Clotting factors specific to each pathway (extrinsic and intrinsic).
What is the most important factor for targeted therapy in coagulation?
Factor X or Stuart factor.
What is fibrinolysis?
The process of breaking down fibrin in blood clots.
Which factors are involved in the extrinsic pathway?
Factors III, VII, and X.
What is the tenase complex composed of?
Factor IXa, Factor VIIIa, Ca²⁺, and negatively charged phospholipids.
What happens when tissue factor, factor VII, and calcium ions mix?
Factor X is converted into its activated form, FXa.
What activates factor X in the intrinsic pathway?
Factor IX together with factor VIII and Ca2+ generates intrinsic tenase.
What triggers the intrinsic pathway?
Contact with negatively charged surfaces.
What is the difference between thrombocytopenia and thrombocytosis?
Thrombocytopenia is low platelet count, while thrombocytosis is elevated platelet count, which can increase clotting risk.
Where are most clotting factors formed?
In the liver.
What is the final product of the coagulation process?
Fibrin, which forms a mesh trapping more platelets and erythrocytes to produce a clot.
What is the Fitzgerald factor also known as?
High-molecular-weight kininogen (HMWK).
What is the main purpose of coagulation tests?
To assess the total function of the coagulation cascade and measure the time it takes for fibrin strands to form after an injury.
What does Factor XIIa cleave Factor XI into?
Factor XIa.
How does the extrinsic pathway compare to the intrinsic pathway?
It is quicker responding and more direct.
What does the tenase complex convert Factor X into?
Factor Xa.
What is the role of the prothrombinase complex?
It converts prothrombin to thrombin.
What role does thrombin play in the clotting process?
Thrombin converts fibrinogen to fibrin, stabilizing the platelet plug.
What is Thrombocytopenia?
A condition characterized by a very low platelet count.
What is the function of plasmin?
It breaks down fibrin, fibrinogen, and various coagulation factors.
What is the role of plasmin in hemostasis?
It dissolves the clot by breaking down fibrin and fibrinogen.
What is the normal range for clotting time?
6 to 10 minutes.
What are the key components released from activated platelets?
ADP, ATP, serotonin, vWF, clotting factor V, and fibrinogen.
What activates Factor IX in the coagulation cascade?
Factor XIa combined with Ca²⁺.
What factors are important for clot prevention?
Smoothness of the endothelial cell surface and the presence of thrombomodulin and thrombin complex.
What marks the convergence of intrinsic and extrinsic pathways?
The formation of prothrombin activator.
What does thrombin convert fibrinogen into?
Fibrin fibers.
What are antiplatelet agents, and give two examples?
Agents that inhibit platelet activation; examples include Aspirin and Clopidogrel.
What defines a thrombus?
Aggregates of platelets and erythrocytes trapped within a mass of fibrin strands.
What are the three essential steps in the coagulation cascade?
What conformational change occurs in GPIIb/IIIa during platelet activation?
It allows GPIIb/IIIa to bind fibrinogen, forming bridges between platelets.
What initiates the process of fibrinolysis?
The conversion of plasminogen to plasmin.
What catalyzes the conversion of plasminogen to plasmin?
Tissue plasminogen activator or urokinase-type plasminogen activator.
What happens when Factor XII comes into contact with a negatively charged surface?
It is converted into its active form, XIIa.
What is Disseminated Intravascular Coagulation (DIC)?
A condition where large amounts of tissue factor are released, leading to numerous small clots and bleeding tendencies.
What is the other name for clotting Factor IV?
Calcium
