Abstract

The process by which body provides protection by producing antibodies to fight with antigens is considered to be immunity. Antibody is developed either from organic compound or pathogenic substances and non-pathogenic substances. Mucous membrane forms an external lining of the conjunctive digestive tract, alimentary canal, respiratory canal, and urogenital tract. This consists of epithelial layer and the inner connective tissue layer. The mucus secretion along with saliva and tears contain antibacterial or antiviral substances that wash away microbes that invade the outer layer. Due to its viscous nature the mucous secreted by the outer epithelial layer entraps the invading microbes. The mucous membrane in the lower respiratory tract is normally covered with cilia which are hair like projections that can propel mucous entrapped microbes. The pathogenic micro organisms outside will have to complete with the non pathogenic microbial flora already colonizing the mucous cilial niches which prevent them from entering the body through the membrane. These mucous membrane barriers are sometimes evaded by certain microbes.