There are 2 lines of nonspecific defenses that are available for the body to use. The first of these are external defenses, such as mucous, skin, and hair. The second line of defense is the internal one, including inflammatory, temperature, protein, and white blood cell responses.
Two Lines of Nonspecific Defenses
Most animals depend on their immune system to protect them from pathogens, or disease causing agents. The immune system is composted of many cells and tissues throughout the body. Both nonspecific and specific defenses are utilized by the body. As for nonspecific defenses, there are 2 lines, or groups, used to destroy pathogens.
First Line of Nonspecific Defenses
The first line of the body's nonspecific defenses are the surface defenses. The skin in particular is the primary line of defense being that it prevents pathogens from entering the body. The skin is aided by chemical protectors such as sweat and oils that further kill and remove pathogens that may be present. Mucous membranes such as those found in the nose and the lining of the digestive tract kill pathogens as well. Hair also acts as another barrier. However, when a pathogen manages to penetrate the skin or enters the body for any reason, the second line of defenses take over.
Second Line of Nonspecific Defenses
When pathogens break through the body's first line of defense, the second line of defense is put into place. This 4 part system includes the inflammatory response, the temperature response, proteins, and white blood cells. The inflammatory response occurs for a localized injury or infection. The response is a chain of events utilized to suppress infection and speed recovery. This includes the release of the chemical Histamine, which dilates blood vessels and in turn increases blood flow to the site of the wound. This, in turn, allows more white blood cells to attack the infection and kill it. This typically leads to swelling and redness of the infected or injured area. The temperature response is the body increasing it's core body temperature a couple degrees, in order to kill an infection. A prime example of a temperature response is a fever. Fevers are an illness that actually aid the killing of bacteria. However, fevers over 103 degrees F are dangerous, and over 105 degrees F can be fatal. Proteins of many varieties aid in killing pathogens as well. One particular group of 20 proteins is called the complement system. These proteins are constantly circulating in the body's blood vessels, and only activate when infection is detected. White blood cells come in 3 different varieties: Neutrophils, Macrophages, and Natural Killer Cells. They each have their own unique way of killing bacteria and pathogens.