Haemostasis and Coagulation Processes

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Questions and Answers

What is the initial trigger for under-activity of fibrinolysis?

Release of clotting factors

External pressure on a wound

Vascular endothelial damage (correct)

Increase in platelet production

Which method is NOT commonly used to control haemorrhage in dentistry?

Pressure application

Sutures

Cold compress (correct)

Packing with haemostatic agents

How long should normal bleeding typically stop after a dental procedure?

1-2 minutes

30-60 minutes

10-30 minutes

4-10 minutes (correct)

What is one of the less commonly used methods for coagulating tissue in dentistry?

Electrosurgery unit Signup and view all the answers

Which aspect of haemostasis is particularly relevant to dental hygienists and therapists?

Describing the process of clot formation Signup and view all the answers

What is the main function of adenosine diphosphate (ADP) in haemostasis?

It attracts other platelets to the site. Signup and view all the answers

In which condition is bleeding time likely to be prolonged?

Thrombocytopenia Signup and view all the answers

What triggers the extrinsic pathway in the coagulation process?

Tissue factor released by damaged endothelial cells. Signup and view all the answers

What is the normal value range for Prothrombin Time (PT)?

11-16 seconds Signup and view all the answers

Which factor is activated first in the intrinsic pathway of coagulation?

Factor XII Signup and view all the answers

What is the primary function of haemostasis?

To stop bleeding when a blood vessel is damaged Signup and view all the answers

Which stage of haemostasis involves the constriction of blood vessels?

Vasoconstriction Signup and view all the answers

Which substance is released by platelets to aid in their aggregation during primary haemostasis?

Serotonin Signup and view all the answers

What is the significance of von Willebrand factor in primary haemostasis?

It stabilizes the platelet plug Signup and view all the answers

Which of the following is a consequence of severe blood loss?

Rapid heart rate Signup and view all the answers

In secondary haemostasis, what primarily forms the blood clot?

Fibrin Signup and view all the answers

Which symptom is NOT associated with moderate blood loss?

Clammy, cold skin Signup and view all the answers

What role do vasoconstrictors like endothelins play in haemostasis?

They induce blood vessel constriction Signup and view all the answers

What is the normal value range for Activated Partial Thromboplastin Time (aPTT)?

23-35 seconds Signup and view all the answers

Which factors are associated with inherited disorders such as Hemophilia?

Factor VIII, IX, and XI Signup and view all the answers

Which drug is commonly used as an anticoagulant for preventing stroke?

Warfarin Signup and view all the answers

What role does thrombin play in coagulation?

It converts fibrinogen into fibrin strands Signup and view all the answers

What is a major effect of anticoagulants on the coagulation cascade?

To block specific clotting cascade processes Signup and view all the answers

What occurs during clot retraction?

Serum is produced Signup and view all the answers

Which condition can lead to depressed fibrinolysis?

Chronic renal disease Signup and view all the answers

What is the primary cause of thrombosis?

Over-activity of coagulation Signup and view all the answers

Study Notes

Haemostasis

Haemostasis is the process of stopping bleeding
Process involves vasoconstriction, platelet plug formation, and coagulation

Primary Haemostasis

Primary haemostasis includes vasoconstriction and platelet plug formation
Platelets stick to damaged blood vessel walls and release serotonin and thromboxanes

Secondary Haemostasis

Secondary haemostasis involves the formation of a stable fibrin mesh
The clotting cascade activates factors to form fibrin from fibrinogen
Fibrin mesh traps red and white blood cells

Clotting Cascade

The clotting cascade involves a series of enzymatic reactions that lead to the formation of fibrin
The extrinsic pathway is initiated by tissue factor, released from damaged endothelial cells
The intrinsic pathway is triggered by collagen exposed in the blood vessel wall due to damage
Both pathways lead to the formation of a common pathway that ultimately leads to fibrin

Coagulation Factors

Most coagulation factors are synthesized in the liver
Vitamin K is essential for the formation of clotting factors in the liver

Clot Retraction

Clot retraction is the shrinking of the clot within 24 hours.
Actin and myosin proteins within activated platelets pull the clot tight

Fibrinolysis

Fibrinolysis is the process of breaking down the clot through the activation of plasminogen to plasmin
Thrombin-activated fibrinolysis inhibitor (TAFI) is a fibrinolysis inhibitor that helps stabilize clots

Thrombosis

Thrombosis is the formation of a blood clot inside a blood vessel
Thrombosis can be caused by over-activity of coagulation, under-activity of fibrinolysis, or both

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Description

This quiz covers the essential processes of haemostasis, including primary and secondary haemostasis, and the clotting cascade. Learn about the roles of platelets and coagulation factors in stopping bleeding and forming clots. Test your knowledge on how these processes work together to maintain hemostasis.