Mucus

Mucous cells of the stomach lining secrete mucus (pink) into the lumen

Mucus (/ˈmjkəs/ MEW-kəs) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is a viscous colloid containing inorganic salts, antimicrobial enzymes (such as lysozymes), immunoglobulins (especially IgA), and glycoproteins such as lactoferrin[1] and mucins, which are produced by goblet cells in the mucous membranes and submucosal glands. Mucus serves to protect epithelial cells in the linings of the respiratory, digestive, and urogenital systems, and structures in the visual and auditory systems from pathogenic fungi, bacteria[2] and viruses. Most of the mucus in the body is produced in the gastrointestinal tract.

Amphibians, fish, snails, slugs, and some other invertebrates also produce external mucus from their epidermis as protection against pathogens, to help in movement, and to line fish gills. Plants produce a similar substance called mucilage that is also produced by some microorganisms.[3]

  1. ^ Singh, PK; Parsek, MR; Greenberg, EP; Welsh, MJ (May 2002). "A component of innate immunity prevents bacterial biofilm development". Nature. 417 (6888): 552–555. Bibcode:2002Natur.417..552S. doi:10.1038/417552a. PMID 12037568. S2CID 4423528.
  2. ^ Barr et al. Bacteriophage adhering to mucus provide a non–host-derived immunity PNAS 2013
  3. ^ "Modes of locomotion in protists: 5 modes". biology discussion. 2016-09-06.