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How does vasodilation increase blood flow to an injured area?

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Pathways of complement activation — inflammation The main function of complement proteins is to aid in the destruction of pathogens by piercing their outer membranes (cell lysis) or by making them more attractive to phagocytic cells such as macrophages (a process known as opsonization). Some complement components also promote inflammation by stimulating cells to release histamine and by attracting phagocytic cells to the site of infection.

Following an injury, the body initiates an acute inflammatory response to protect and repair damaged tissue. While small blood vessels initially undergo a brief period of vasoconstriction, they quickly transition to vasodilation.1

Vasodilation increases blood flow to the injured area by widening the diameter of arterioles, which are the small arteries responsible for regulating blood entry into capillary networks. This process is triggered by various chemical mediators released from damaged cells and immune components, such as histamine, which is stored in mast cells and basophils.23

By increasing the vessel diameter, the body facilitates a greater volume of blood reaching the site of injury. This heightened flow is essential for delivering white blood cells and protein-rich exudate to the area, which contain clotting factors and antibodies necessary to contain infectious agents and begin the healing process.13