From which among the following are blood clotting factors released?

Blood clotting, or haemostasis, is a critical process to prevent excessive blood loss from injuries. Platelets (thrombocytes) are specialized cell fragments that circulate in the blood to plug leaks by forming a clot at the site of injury [2]. When a vessel is damaged, platelets adhere to the site and become activated, releasing various substances from their secretory granules [4]. Specifically, platelet ̑-granules contain essential clotting factors such as fibrinogen and von Willebrand factor [4]. These released factors, along with others present in the plasma, initiate a coagulation cascade that converts fibrinogen into a fibrin mesh, stabilizing the platelet plug. While other cells like monocytes can express tissue factor to initiate coagulation, platelets are the primary cellular source that releases stored clotting factors and provides the phospholipid surface necessary for the propagation of the clot [4].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > Maintenance by platelets > p. 94
2. [2] https://www.ncbi.nlm.nih.gov/books/NBK2263/
3. [4] https://www.khanacademy.org/science/biology/human-biology/circulatory-pulmonary/a/components-of-the-blood