Final answer:
Histamine makes blood vessels leaky and attracts phagocytic cells to the injured area. It plays a role in the inflammatory response and is released by certain cells when there is an injury or infection.
Step-by-step explanation:
Histamine makes blood vessels leaky and attracts phagocytic cells to the injured area. When certain cells, such as mast cells, detect an injury or infection, they release histamine, which causes the capillaries to dilate and become more permeable. This increased permeability allows immune cells, such as phagocytes, to exit the bloodstream and move towards the site of injury or infection. Histamine also plays a role in the redness and swelling associated with inflammation.