Free Essays, Term Papers, Research Papers at Anti Essays

Haemostasis

Introduction:
Haemostasis is a process that prevents excessive blood loss form the body. Most times this includes turning the blood from a liquid to a solid state. There are three main processes the body goes through during haemostasis to contorol bleeding, these include, vascular spasm, platelet plug, and blood clotting.
Vascular spasm:
Vascular spasm occurs when a blood vessel is punctured. The vessels muscle contracts and stops blood supply to the punctured vessel. This occurance can be seen as the bodies form of first aid, the body can hold this for minutes or even hours. The vasular spasm happens because of the pain receptors in the body, which makes the muscles contract.

Platelet Plug Formation:
Platelet plug formation has three stages unlike the process of Vascular spasms. These three stages include:
Platelet adhesion - The first phase begins when platelets detect damage to a blood vessel and begin to adhere to the exposed surfaces.
Platelet release reaction - This phase is when the platelets releases granules to asist with the clotting process. This is the stage that makes the the process of making a paltelet work, its a very important stage of making platelet plugs. Firstly the platelets create extentions so that they can contact each other, then they are able to release there contents. There are two types of granules held within the cytoplasm of platelets: alpha granules that contain clotting factors, growth factors, and fibroblasts, and dense granules that contain ADP, ATP, Calcium ions, and Serotonin. Other components are also present within the platelet that assists the process. Nearby platelets are stimulated into action by the release of ADP and other chemicals.
Platelet aggregation - The ADP acts to make the nearby platelets sticky and stick to the other platelets. When the collection of platelets is large enough it creates a platelet plug stopping the loss...