Final answer:
Mast cells trigger an inflammatory response during the inflammatory phase of repair, releasing chemicals that cause symptoms such as redness, warmth, and swelling.
Step-by-step explanation:
Mast cells play a critical role in the body's response to injury by triggering the inflammatory response. During the inflammatory phase of repair, mast cells release chemical signals such as histamine and heparin. This release initiates vasodilation, which increases blood flow, and makes the capillaries more permeable, leading to the characteristic symptoms of inflammation like redness, warmth, and swelling. Therefore, mast cells are triggering a response to injury during the Inflammatory phase of repair.