Which of the following statements is true concerning the vascular response to injury?
After wounding, there is transient vasoconstriction mediated by catecholamines, thromboxane, and prostaglandin F2 (PGF2a). This period of vasoconstriction lasts for only five to ten minutes. Once a clot has been formed and active bleeding has stopped, vasodilatation occurs in an around the wound. Vasodilatation increases local blood flow to the wounded area, supplying the cells and substrate necessary for fuher wound repair. The vascular endothelial cells also deform, increasing vascular permeability. The vasodilatation and increased endothelial permeability is mediated by histamine, PGE2, and prostacyclin as well as growth factor VEGF (vascular endothelial cell growth factor). These vasodilatory substances are released by injured endothelial cells and mast cells and enhance the egress of cells and substrate into the wound and tissue.
Vasoconstriction is an early event in the response to injury
Vasodilatation is a detrimental response to injury with normal body processes working to avoid this process
Vascular permeability is maintained to prevent fuher cellular injury
Histamine, prostaglandin E2 (PGE2) and prostacyclin (PGI2) are impoant mediators of local vasoconstriction