What occurs when a piece of plaque breaks free inside a blood vessel?

When a piece of plaque breaks free inside a blood vessel, the body responds to the injury in the vessel wall by initiating the formation of a thrombus at that site. This process occurs as a protective mechanism. When the plaque ruptures, it exposes underlying materials in the vessel wall to the bloodstream, which can trigger the coagulation cascade. Blood platelets aggregate at the site of the injury, leading to the formation of a clot (thrombus) to minimize blood loss. This thrombus can further obstruct blood flow, which may lead to serious conditions such as heart attacks or strokes if the clot travels and lodges in a narrower part of the vascular system.

The other options do not accurately describe the physiological response to a plaque rupture. Dilation of the artery would not typically occur after a rupture as the body is instead trying to manage the injury. Enhanced blood flow is unlikely, as the presence of a thrombus would actually impede flow rather than enhance it. Lastly, complete dissolution of the plaque does not occur immediately upon rupture; instead, it typically requires more complex biological processes that may take place over time, and in many cases, the ruptured plaque does not dissolve completely.