What protections does the innate immune system provide?

The innate immune system is the body’s first line of defense. Its primary aim is to attack the invading pathogens and prevent infection. It achieves this through three protection mechanisms: 

Physical Barriers: Physical barriers such as the skin, mucus membranes and eyelashes form the primary defense by blocking invaders from entering the body. 

Chemical Barriers: Substances such as sweat, tears, mucus, stomach acid, and blood clotting factors, which are present at the physical barriers, play a crucial role in weakening or killing the germs that try to breach the primary defense system. 

Chemical Defenses: Chemical defenses involve proteins that are capable of interacting with invaders that breach the physical and chemical barriers. These proteins interact directly or indirectly with the pathogen, triggering reactions that signal for reinforcements from other immune mediators that work together to help defend the body. 

Cellular Defenses: Cellular defenses activate the adaptive immune system. They also recognize and neutralize or destroy non-self entities. Key players in cellular defenses include natural killer cells, phagocytes, and mast cells.