Question

The α granules of platelets contain vWF, fibrinogen, and fibronectin, as well as PF4 and PDGF. What other substances are found in the α granules of platelets?

1) ADP and serotonin
2) Collagen and elastin
3) Heparin and histamine
4) Thrombin and plasmin

Answer 1

The α granules of platelets contain substances such as ADP and serotonin, which are essential for reinforcing the platelet plug and maintaining vasoconstriction during the hemostatic process.

Step-by-step explanation:

The α granules of platelets are rich in substances that are essential for the hemostatic process. Besides vWF (von Willebrand factor), fibrinogen, fibronectin, PF4 (platelet factor 4), and PDGF (platelet-derived growth factor), they also contain adenosine diphosphate (ADP) and serotonin. ADP plays a crucial role in reinforcing and expanding the platelet plug by helping additional platelets adhere to the injury site, while serotonin acts to maintain vasoconstriction, which is the constriction of blood vessels to reduce blood flow and limit blood loss at the site of an injury.