text: 具体表现在：①当血管受损发生出血时，机体立即通过神经和体液双重调控使该部位血管持续收缩达15～30分钟，此期间血流缓慢，有利于局部血栓的形成和止血；②由于血管内皮受损后胶原组织暴露，它促使血小板发生黏附、聚集和释放反应形成血小板栓子，又能激活凝血因子Ⅻ，启动内源性凝血；③损伤的血管壁释放组织因子，启动外源性凝血过程；④损伤的血管壁产生或释放的抗止血作用物质诸如前列腺素、组织纤溶酶原激活物（t-PA）和抗凝血酶Ⅲ（AT-Ⅲ）减少；而促凝血物如组织纤溶酶原激活物抑制剂（t-PA）、vWF等物质增多，能增强止血反应和加固止血血栓而止血。
entities.entity: 血管
entities.label: bod
entities.entity: 血管
entities.label: bod
entities.entity: 血管
entities.label: bod
entities.entity: 血小板
entities.label: bod
entities.entity: 血小板栓子
entities.label: bod
entities.entity: 凝血因子Ⅻ
entities.label: bod
entities.entity: 血管壁
entities.label: bod
entities.entity: 血管壁
entities.label: bod
entities.entity: 前列腺素
entities.label: bod
entities.entity: 组织纤溶酶原激活物
entities.label: bod
entities.entity: t-PA
entities.label: bod
entities.entity: 抗凝血酶Ⅲ
entities.label: bod
entities.entity: AT-Ⅲ
entities.label: bod
entities.entity: 促凝血物
entities.label: bod
entities.entity: 组织纤溶酶原激活物抑制剂
entities.label: bod
entities.entity: t-PA
entities.label: bod