MICROANATOMY

Detailed explanation-1: -Vasoconstriction is the narrowing of blood vessels, typically when the muscles of blood vessel walls become constricted, causing the vessel lumen to become smaller. Vasoconstriction can be a reaction to cold, stress, cigarette smoking, medications, or underlying medical conditions, such as the Raynaud phenomenon.

Detailed explanation-2: -Vasoconstriction phase. Primary hemostasis is characterized by vasoconstriction, which is the initial phase for stopping the blood flow10. Vascular spasm occurs whenever there is an injury or damage to the blood vessels. This will trigger a vasoconstriction, which could eventually stop the blood flow.

Detailed explanation-3: -Vasoconstriction reduces the volume or space inside affected blood vessels. When blood vessel volume is lowered, blood flow is also reduced. At the same time, the resistance or force of blood flow is raised. This causes higher blood pressure.

Detailed explanation-4: -Primary hemostasis may also involve constriction (narrowing) of the damaged blood vessel, which can happen because of substances that activated platelets release.