Final answer:
Vascular spasms during hemostasis constrict blood vessels to reduce blood flow and prevent further bleeding.
Step-by-step explanation:
Vascular spasms during hemostasis result in the contraction of smooth muscles in the walls of the damaged blood vessel. This leads to the narrowing of the blood vessel, reducing blood flow and preventing further bleeding. The development of a platelet plug and blood clotting are subsequent steps in hemostasis, which help in the long-term sealing and healing of the vessel.