Which chemicals do platelets store and transport to facilitate clot formation?

Which chemicals do platelets store and transport to facilitate clot formation?

• A. Serotonin, epinephrine, histamine, and thromboxane
• B. Insulin and glucagon
• C. Oxygen and carbon dioxide
• D. Adenosine and ATP

Answer: (A)

Platelets carry a set of signaling chemicals in their dense granules that are released when a vessel is injured to drive clot formation. Serotonin is released and causes local vasoconstriction, helping to slow blood loss. Epinephrine stored in platelets can boost that vasoconstriction and support platelet activation. Histamine in platelet granules also modulates the surrounding blood vessels to create an environment favorable for clotting. Thromboxane A2 is produced by activated platelets and acts as a strong vasoconstrictor and promoter of further platelet aggregation, reinforcing the plug. The other options miss these key platelet-derived mediators or describe substances not primarily stored in platelets, so they don’t fit as well.

Platelets carry a set of signaling chemicals in their dense granules that are released when a vessel is injured to drive clot formation. Serotonin is released and causes local vasoconstriction, helping to slow blood loss. Epinephrine stored in platelets can boost that vasoconstriction and support platelet activation. Histamine in platelet granules also modulates the surrounding blood vessels to create an environment favorable for clotting. Thromboxane A2 is produced by activated platelets and acts as a strong vasoconstrictor and promoter of further platelet aggregation, reinforcing the plug. The other options miss these key platelet-derived mediators or describe substances not primarily stored in platelets, so they don’t fit as well.