Which enzyme is responsible for converting fibrinogen to fibrin in the coagulation cascade, and what is its primary activator?

A Thrombin, activated by tissue factor ✓
B Plasmin, activated by urokinase
C Factor Xa, activated by factor VIIa
D Prothrombin, activated by factor V

Explanation

Thrombin is the enzyme that converts fibrinogen to fibrin, forming the clot. It is primarily activated by the tissue factor-factor VIIa complex.

Mnemonic

'Thrombin Time' - remember that thrombin 'times' the conversion of fibrinogen to fibrin

Source

Hematology: Clinical Principles and Applications
Hematology Hematology: Blood Components Hematology: Blood Components Hard MEDICAL Confidence: high