MICROANATOMY

Detailed explanation-1: -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-2: -Hemostasis is the mechanism that leads to cessation of bleeding from a blood vessel. It is a process that involves multiple interlinked steps. This cascade culminates into the formation of a “plug” that closes up the damaged site of the blood vessel controlling the bleeding.

Detailed explanation-3: -Vasospasm of the blood vessels occurs first in response to injury of the vasculature. This vasospasm, in turn, stimulates vasoconstriction. Vasoconstriction is primarily mediated by endothelin-1, a potent vasoconstrictor, which is synthesized by the damaged endothelium.

Detailed explanation-4: -Blood clotting normally occurs when there is damage to a blood vessel. Platelets immediately begin to adhere to the cut edges of the vessel and release chemicals to attract even more platelets. A platelet plug is formed, and the external bleeding stops.

Detailed explanation-5: -Vasoconstriction is caused by thromboxane A2 from activated platelets and injured epithelial cells, nervous system reflexes from pain, and direct injury to vascular smooth muscle. Vasopressins are drugs that may induce vasoconstriction and increase blood pressure.