What initiates the inflammatory response following cellular injury?

The initiation of the inflammatory response following cellular injury is primarily driven by altered metabolism and the liberation of materials that signal distress within the affected tissues. When cells are damaged, they undergo metabolic changes that lead to the release of signaling molecules, such as cytokines and chemokines. These substances play a crucial role in attracting immune cells to the site of injury and starting the healing process.

The liberation of materials also involves the release of damaging molecules and signals that inform surrounding cells of the injury, facilitating a coordinated response from the immune system. This response is essential for containing potential infections, removing debris, and beginning the repair of damaged tissues.

In contrast, while histamine release and blood vessel dilation are components that occur during the inflammatory response, they are not the initial triggers. Histamine release contributes to the vascular changes and increased permeability that characterize inflammation, whereas dilated blood vessels stem from the cascade of events initiated by injury and cellular signaling. Increased physical activity does not initiate inflammation; instead, it could exacerbate existing inflammatory responses in some contexts.