The innate immune system contains many proteins and molecules that are essential to extracellular, and therefore intracellular, defense. The epithelial cell lining of the gastrointestinal and urogenital tract contain mucosal membranes and antimicrobial substances that prevent a pathogen from causing severe damage to the individual's health. 

Extracellular Processes

If a pathogenic microorganism makes its way past the body's first line of defense (including mechanical and chemical barriers) and is not evaded by extracellular processes of the innate immune system, then intracellular defenses of the immune system are essential. These defenses include: 
- phagocytosis
- inflammation

Intracellular Processes

In order to protect the body, the following systems are involved in the innate immune system and have been organized into two categories: 
- Extracellular Processes 
- Intracellular Processes 


Tulane University

State University of New York at Buffalo

All components of the innate immune response are the result of germ-line genes of the host organism.  Some of these defense structures are always active, such as barriers, mucus, and cilia, but the molecular responses become active when a host cell or protein comes into contact with the invading foreign entity.  Some of these elements work in tandem with the adaptive immune response by activating antigen-specific cells.

Components of the Innate Immune Response

Wikipedia

Parham, P. (2009). Vaccination to Prevent Infectious Disease. In 1145902806 862124677 J. Foltin (Ed.), The Immune System (3rd ed., pp. 62-65). New York, New York: Garland Science, Taylor & Francis Group.

The Immune System

Processes of the innate immune system

Types of nonspecific innate immune defenses include:
- Physical defenses
- Chemical defenses
- Cellular defenses

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