50 Questions
What is the primary function of the body's process of hemostasis?
To prevent excessive hemorrhage following tissue injury
What is the immediate response of the blood vessel wall when its integrity is interrupted?
Vasoconstriction
What is the role of prostacyclin PGI2 in the vascular phase?
It prevents platelet activation and sticking to the blood vessel wall
What is the second stage of hemostasis?
Platelet plug formation
What is the result of vasoconstriction in the vascular phase?
Decreased blood flow to the injured area
What is the primary role of platelets in hemostasis?
To form a platelet plug
What is the relationship between the three interrelated systems of hemostasis?
They are interrelated and dependent on each other
What is the primary difference between small capillary tears and large blood vessel cuts?
The body's ability to control the bleeding
What is the primary function of Antithrombin III in the coagulation system?
To inactivate thrombin and prevent clot expansion
What is the role of Protein C and S in the coagulation system?
To inactivate activated factors 5 and 8
What is the effect of heparin on the coagulation system?
It prevents further expansion of the clot
What is the role of t-PA in the coagulation system?
To leak small amounts of clot-dissolving enzymes into the clot
What is the effect of FDP (fibrin degradation products) on the coagulation system?
They act as anticoagulants
What is the primary site of Antithrombin III synthesis?
Liver and endothelial cells
What is the consequence of deficiencies in Protein C and S?
Increased risk of thrombosis
What is the primary source of heparin production?
Basophils
What is the effect of a single dose of aspirin on platelet function?
Decreases platelet aggregation
Why does aspirin have 'anticlotting' effects?
Due to irreversible inhibition of cycloxygenase
What is the difference between the effects of aspirin and ibuprofen on platelet function?
The effects of aspirin are irreversible, while those of ibuprofen are reversible
What is the characteristic of Disseminated Intravascular Coagulation (DIC)?
Formation of multiple small blood clots throughout the microvascular
What is the ultimate outcome of Disseminated Intravascular Coagulation (DIC)?
Hemorrhages at all bodily orifices and sites of injury
What triggers Disseminated Intravascular Coagulation (DIC)?
Triggering event, such as infection or trauma
What happens to the components of the blood clotting cascade and platelets during Disseminated Intravascular Coagulation (DIC)?
They are consumed rapidly and become inadequate for hemostasis
What is the relationship between Disseminated Intravascular Coagulation (DIC) and hemorrhage?
DIC causes hemorrhage
What is the primary goal of treating Disseminated Intravascular Coagulation (DIC)?
Stopping the triggering event
What is the mechanism by which heparin therapy works in DIC?
By blocking thrombin formation
What type of thrombosis is more likely to form under conditions of high blood flow?
Arterial thrombosis
What is a common etiology of venous thrombosis?
Increased red cell mass and viscosity
What is the term for the three conditions that lead to hypercoagulability?
Virchow's triad
What is a consequence of thrombus formation in a blood vessel?
Blockage of blood flow
What is the main component of arterial thrombi?
Platelet aggregates
What is the result of hypercoagulability in an individual?
Predisposition to develop thrombi
What is a common presentation of antithrombin III deficiency in healthy young adults?
Myocardial infarction, stroke, or pulmonary emboli
What is the treatment for protein C deficiency?
FFP and monoclonal protein C concentrate
What is the mode of inheritance of protein S deficiency?
Autosomal dominant
What is the primary function of protein C in the coagulation pathway?
Inactivation of factor V
What is the typical presentation of antithrombin III deficiency during pregnancy?
Deep vein thrombosis, pulmonary emboli
What is the underlying mechanism of factor V Leiden mutation?
Activated protein C resistance
What is the relationship between liver disease and antithrombin III deficiency?
Antithrombin III deficiency can be acquired secondary to liver disease
What is the presentation of protein C deficiency in neonates?
Renal vein thrombosis, umbilical thrombosis
What is the primary function of the intrinsic pathway in the coagulation cascade?
To converge with the extrinsic pathway to form a common pathway
Which of the following factors is NOT involved in the final stages of clot formation?
Factor XI
What is the role of plasminogen activator inhibitor-1 (PAI-1) in the fibrinolytic pathway?
To regulate the fibrinolytic pathway
What is the characteristic of bleeding disorders that is most often associated with impaired primary hemostasis?
Defects in platelet function or number
Which of the following is a vitamin K-dependent factor?
Factor VII
What is the result of the convergence of the intrinsic and extrinsic pathways in the coagulation cascade?
The formation of a fibrin clot
What is the primary function of tissue plasminogen activator (tPA) in the fibrinolytic pathway?
To convert plasminogen to plasmin
What is the characteristic of bleeding disorders that is most often associated with coagulation disorders?
Easy bruising or bleeding
Which of the following is a contact factor involved in the coagulation cascade?
Factor XI
What is the result of the breakdown of fibrin by plasmin in the fibrinolytic pathway?
The restoration of blood flow
Study Notes
Coagulation Cascade
- A series of chemical reactions leading to blood clot formation
- Involves activation of coagulation factors (proteins produced by the liver)
- Divided into two pathways: extrinsic and intrinsic
- Extrinsic pathway: triggered by tissue factor from damaged tissues
- Intrinsic pathway: triggered by collagen exposure in damaged blood vessels
- Both pathways converge to form a common pathway, resulting in thrombin and fibrin clot formation
Blood Clotting Factors
- 13 clotting factors (I-XIII) involved in coagulation cascade
- Each factor has a specific role in blood clot formation
- Factors categorized into three groups:
- Vitamin K-dependent factors: II, VII, IX, and X
- Contact factors: XI, XII, and prekallikrein
- Fibrinogen and factor XIII: involved in final stages of clot formation
Fibrinolytic Pathway
- Process that breaks down blood clots to restore blood flow
- Involves activation of plasminogen, converted to plasmin by tissue plasminogen activator (tPA)
- Plasmin breaks down fibrin, dissolving the blood clot
- Fibrinolytic pathway regulated by inhibitors, including plasminogen activator inhibitor-1 (PAI-1)
Bleeding Disorders
- Classified into two main categories:
- Coagulation disorders: defects in coagulation cascade, impairing blood clotting
- Platelet disorders: defects in platelet function or number, impairing primary hemostasis
- Characteristics of bleeding disorders:
- Easy bruising or bleeding
- Prolonged bleeding after injury
- Spontaneous bleeding
- Joint pain or swelling due to bleeding into joints
- Fatigue and weakness due to anemia
- Bleeding disorders can be inherited or acquired, caused by deficiencies in clotting factors, platelet dysfunction, or other factors
Learn about the process of hemostasis, how the body prevents excessive bleeding, and the difference between small capillary tears and large blood vessel cuts. Understand the simultaneous biochemical reactions involved in hemostasis and their importance in preventing hemorrhage.
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