The role of the immune system, however, is simple. It creates barriers and maintains those barriers to prevent viruses and bacteria from entering the body. It strives to keep us healthy and free of infection.
However, it is not a perfect system and human's do get sick. When infection strikes (pathogens enter the body), the innate immune system detects these pathogens. If the response is quick enough and efficient enough, often this "first strike team" can eliminate the infection before it turns into an even bigger one.
Since the skin is the body's first layer of defense, literally, it is by nature able to withstand much of the onslaught of germs within our environment. Inflammation (redness and swelling) is one of the first signs that the innate immune system has kicked in to prevent further infection. It's actually a warning sign your body uses to alert you to a problem.
The one function the innate system does not have, however, is a "memory" of the infection. The "let's remember what made us sick" function is the responsibility of the adaptive immune system. When the innate immune system's response is not fully effective, the adaptive immune system comes into play. By identifying the invader, the adaptive system is, as the name implies, ready to make moves to block, isolate and learn from the invading pathogen. In this way, the human body "learns" and "adapts" to protect itself from future infection.
Every winter the TV commercials and ads begin warning us of the upcoming cold and flu season. Hand washing is one of the best defenses you can do for your body. Proper hand washing is done with as much hot water as you can stand, lots of soap, scrubbing not only your hands but also your wrists and even up the arms. Follow this up with enough rinsing time (singing the Happy Birthday song in your head is a good measure of "proper length of time."), and you're more than halfway home to protecting yourself during the cold and flu season.
Keeping healthy is an ongoing job. Plenty of sleep, the proper diet to ensure sufficient intake of vitamins and minerals, and exercise are the tasks humans are assigned (outwardly) to stay healthy. The skill and planning involved, however, to keep the body functioning properly remains hidden inside ourselves - the immune system - relentlessly working, untiring in its task.
