Hemostasis means 'stopping blood flow'. It involves constriction of the injured vessel, formation of a platelet plug, and coagulation.
The basic structure is a longitudinal view of a blood vessel. It's wall consist of three layers; from the outside in they are collagen represented by small curliques, smooth muscle represented by a zig-zag line, and endothelium represented by a clear area.
Outside the vessel on the left side, from top to bottom, are an intact cell, a broken cell and a mast cell. Each can be identified by the presence of a nucleus shown as a shaded circle. The red specks within the intact cell and being released from the broken cell represent cellular contents such as tissue prothrombin activator, TPA. Cells also contain tissue factor here represented as complex of yellow particles.
Within the vessel are numerous platelets represented by ovals. The shaded hexagons represent clotting factors. On the right inner vessel surface are three bold arrows that represent compounds that are released into the blood by the endothelium.
Last Updated: 7/19/2005