The origin and functions of nasal mucus.

Using histochemical techniques the source and nature of nasal mucus and secretions has been investigated. The secretions from the serous and mucous glands in the stroma consist of acid mucopolysaccharides and mucoprotein. The mucins from the goblet glands are similar but sulfated. The large ducts have a secretory function also. The capillary net lies in the epithelium, allowing rapid transudation to take place. The basement membrane is PAS negative during early life and is permeable. It becomes progressively more PAS positive with age because of this. A comparative study of the uses of mucus has shown that its physio-chemical characteristics are the most prominent. Mucus may act as a retainer for substances, exhibit surface electrical activity, have permeability and act as a mesh. It is an adhesive, protects the mucosa and transports particulate matter. It allows heat transfer and has water holding properties. It is suggested that mucus has been utilized throughout evolution because of its protean physiochemical properties. [ABSTRACT FROM AUTHOR]