Final answer:
The immune system defends against pathogens using two mechanisms: the innate immune response and the adaptive immune response. The adaptive immune system employs highly specific defenses such as T cells and B cells to target and destroy pathogens, providing a more sophisticated level of immune combat with memory capabilities.
Step-by-step explanation:
If a pathogen manages to find its way past your body's initial defenses, your immune system can still fight with its more advanced mechanisms, known as the adaptive immune response. This system includes specialized cells that are highly specific and effective at attacking a wide variety of pathogens, such as bacteria and viruses. The adaptive immune response employs T cells and B cells that specifically target and destroy invading pathogens. B cells produce antibodies that bind to antigens on the surface of pathogens, marking them for destruction, while T cells can directly kill infected host cells or help other immune cells perform their functions.
Despite the barriers of skin, tears, and mucus, once a pathogen enters the body, the innate immune system first responds with non-specific defenses. However, if these are bypassed, the adaptive immune response provides a targeted and effective line of defense. This part of the immune system has the remarkable ability to remember pathogens to which it has been exposed, creating a more efficient response upon reexposure, potentially leading to long-lasting immunity.
Moreover, this immune combat is a constant evolutionary race between the immune system's ability to protect the host and the pathogen's ability to evolve evasion strategies. Modern medicine aims to support and advance the immune system and its responses to tip the scales in favor of human health.