when a blood vessel is injured the first phase in hemostasis to occur is coagulation.
when a blood vessel is injured the first phase in hemostasis to occur is?
coagulation
hemostasis occurs when blood is present outside of the body or blood vessels. it is the innate response for the body to stop bleeding and loss of blood. during hemostasis three steps occur in a rapid sequence. vascular spasm is the first response as the blood vessels constrict to allow less blood to be lost. in the second step, platelet plug formation, platelets stick together to form a temporary seal to cover the break in the vessel wall. the third and last step is called coagulation or blood clotting. coagulation reinforces the platelet plug with fibrin threads that act as a "molecular glue". platelets are a large factor in the hemostatic process. they allow for the creation of the "platelet plug" that forms almost directly after a blood vessel has been ruptured. within seconds of a blood vessel's epithelial wall being disrupted platelets begin to adhere to the sub-endothelium surface. it takes approximately sixty seconds until the first fibrin strands begin to intersperse among the wound. after several minutes the platelet plug is completely formed by fibrin. hemostasis is maintained in the body via three mechanisms:
hemostasis
a typical electrothermal bipolar vessel sealing system consists of an electric current generator and an instrument for grasping blood vessels. during surgery, a surgeon first grasps a blood vessel to be sealed with the instrument that is usually designed as a clamp. a surgeon then initiates a sealing cycle controlled by the generator. the generator produces an electric current across the blood vessel wall. electromagnetic wave surrounding the current energizes the electrons within the blood vessel. these electrons release their energy as heat. as the blood vessel is heated, the collagen and elastin found in the blood vessel wall denature. the generator precisely controls the amount of energy delivered to the tissue through a computer algorithm that varies depending on the manufacturer. the majority of the generator systems monitor the impedance in the circuit and as it begins to rise automatically break the current. this prevents charring and burning of the vessel wall. the sealing cycle is complete with a period of cool-down during which the elastin and collagen form a seal. some of the ebvs instruments are also able to cut the formed seal either with a blade incorporated into jaws of the instrument or with a harmonic scalpel technology.
electrothermal bipolar vessel sealing