Fibrinolysis and Haemostasis Concepts

Haemostasis is the body's response to prevent blood loss after vascular injury. It involves the formation of blood clots composed of platelets, red blood cells, and fibrin. The process is regulated by clotting factors. Platelet activation starts when vascular injury exposes collagen and von Willebrand factor, leading to platelet aggregation. Tissue factor initiates the coagulation cascade, resulting in thrombin production, which fully activates platelets and generates fibrin. Fibrin stabilizes the clot, while fibrinolysis eventually breaks it down as the vessel heals.

What is the primary function of haemostasis?

• To increase blood flow

• To limit blood loss after vascular injury

• To decrease blood pressure

• To enhance oxygen transport

What are blood clots primarily composed of?

• Activated platelets, red blood cells, and fibrin

• Water and electrolytes

• Plasma and antibodies

• White blood cells and collagen

What triggers the initial activation of platelets?

• Contact with collagen and von Willebrand factor

• Exposure to air

• Increase in blood pressure

• Decrease in oxygen levels

What role does tissue factor play in haemostasis?

• It increases blood flow

• It decreases platelet production

• It triggers the initiation of the coagulation cascade

• It dissolves blood clots

What is the result of the interaction between tissue factor and Factor 7a and Factor 10a?

• Decrease in blood pressure

• Production of a small amount of thrombin

• Dissolution of the clot

• Increase in oxygen levels

How many molecules of thrombin are produced by one molecule of Factor Xa?

• 10

• 100

• 1000

• 10000

What does thrombin convert fibrinogen into?

• Soluble fibrin

• Insoluble fibrin strands

• Collagen

• Von Willebrand factor

What initiates the process of fibrinolysis?

• Secretion of tissue plasminogen activator by endothelial cells

• Increase in blood pressure

• Activation of Factor Xa

• Decrease in oxygen levels