When the skin or mucous membranes are breached by a pathogen, what is usually the last of the five signs of the inflammatory response?

In the context of the inflammatory response, loss of function is indeed considered to be the last of the five classical signs that indicate an inflammatory process. The five signs are usually described as redness, heat, swelling, pain, and loss of function.

When a pathogen breaches the skin or mucous membranes, the initial response involves local blood vessels dilating and increasing blood flow to the affected area, leading to redness and warmth. As the inflammatory response progresses, fluid and immune cells accumulate in the area, resulting in swelling. Pain often develops as a result of mediators released during inflammation that sensitize nerve endings. Finally, the loss of function can occur due to pain and swelling that inhibit movement or use of the affected area.

This sequence emphasizes the gradual nature of the inflammatory process, where loss of function often represents a culmination of the earlier signs, reflecting the body's overall response to injury or infection.