Components of mucosa
Claudia F. Martinez de la Pena
Hawazen Binmahfouz
Mucosa membrane is in mostly line cavities exposed to external environments. The mainly components
of mucosa are the epithelial cells, secreted specialized cells, mucous and associated immune cells like
dendritic cells and macrophages.(9)
Most mucosal surfaces are covered by a hydrated gel formed by mucins (family of heavily glycosylated
proteins) that are secreted by specialized epithelial cells, such as gastric foveolar mucous cells and
intestinal goblet cells, and create a barrier that prevents large particles, including most bacteria, from
directly contacting the epithelial cell layer. (10)
Oral mucosa
Esophageal mucosa
Gastric mucosa
Intestinal mucosa
GI Tract
Nasal mucosa
Olfactory mucosa
Bronchial mucosa
Respiratory Tract
Uterine mucosa
Penile mucosa
Ocular mucosa
Examples of mucosal composition:
1. Bronchial mucosa:




Epithelium
Lamina propria glands
Vascular tissue
Elastic matrix
(8)
2. Oroesophageal mucosa


stratified squamous epithelial cells
Lamina propria
Fig. 1. Oral mucosa (7).
3. Gastric mucosa (5)



Ephiteliial cells
Special mucous (neck cells)
Biocarbonate ions
4.



Intestinal mucosa
Epithelial cells
Lamina propria
Muscularis mucosa
Fig. 2 and 3. Intestinal Mucosa.
http://www.vetmed.vt.edu/education/Curriculum/VM8054/Labs/Lab18/Lab18.htm#.
http://faculty.southwest.tn.edu/jiwilliams/models_of_the_digestive_system.htm
Mucosa types differentiate in two types according to their primary role and anatomical features.
1. Type I mucosal surfaces represent the Gut, small intestine, colon, lung, airways, alveolar space,
upper female reproductive organ of the intestine, lung, and uterus.
2. Type II mucosal surfaces are represented by those of the oral and vaginal cavities
Type I mucosa are covered by simple epithelial of one cell layer. Their physiological functions are
absorption and respiration. Type I mucosa have specialized cells that secreted mucous like globet cells
and express a polymeric Ig receptor (pIgR), allowing dimeric IgA to access the lumen. Neonatal Fc
receptor is another receptor which can be sometimes found in type I mucosa to transport the IgG. (4)
Type I mucosa is associated with many lymphoid tissue and form Mucosa-associated lymphoid tissue
(MALT), it can be found in gut (gut-associated lymphoid tissue GALT), nose (nasopharynxassociated
lymphoid tissue NALT), bronchial (bronchus-associated lymphoid tissue BALT), conjunctiva- associated
lymphoid tissue (CALT), lacrimal duct-associated (LDALT), larynx-associated (LALT) and salivary ductassociated lymphoid tissue (DALT). The main function of MALT is to produce and secrete IgA across
mucosal. (3). (Fig 4).
Type II mucosa are covered by stratified squamous epithelia (keratinocytes). The main function of type
II mucosa is to provide physical protective barriers for activities that are important for the host species,
such as mastication and coition They lack plgR and thus does not transport IgA into the lumen. A MALT
organised structures are not present in Type II mucosal surfaces but they are drained by regional lymph
nodes. (4) (See fig.4 and 5)
Fig. 4 Type I and Type II mucosae. (4)
Fig. 5.Schematic representation of MALT. (1)
 Mucus:
Mucus is a secretion product of specialized cells present in mucosa which form a layer above epithelial cells.
It consist of mucin fibers that highly adhesive and that traps foreign particulates.
The shear-dependent viscosity of mucus helps maintain an unstirred layer of gel through which particles
must diffuse before they can contact epithelial cells. These unstirred layers of mucus form a diffusional
barrier that helps create much of the selective permeability of the mucus blanket.(2)
Fig. 6. Normal human mucus thickness. (6).

1.
2.
3.
4.
5.
6.
7.
8.
9.
References:
Aguilera Montilla N., P. B. M., Lopez SAntalla M., Martin Villa J.M. 2004. Mucosal immune
system: a Brief review. Inmunologia 23:207-216.
Bienenstock, J. 2005. Mucosal Immunology. Academic Press.
Cesta, M. F. 2006. Normal structure, function, and histology of mucosa-associated lymphoid tissue.
Toxicologic pathology 34:599-608.
Iwasaki, A. 2007. Mucosal dendritic cells. Annual review of immunology 25:381-418.
Konturek, S. J., P. C. Konturek, T. Pawlik, Z. Sliwowski, W. Ochmanski, and E. G. Hahn. 2004.
Duodenal mucosal protection by bicarbonate secretion and its mechanisms. Journal of physiology
and pharmacology : an official journal of the Polish Physiological Society 55 Suppl 2:5-17.
Lai, S. K., Y. Y. Wang, and J. Hanes. 2009. Mucus-penetrating nanoparticles for drug and gene
delivery to mucosal tissues. Advanced drug delivery reviews 61:158-171.
Liu, J., Z. Bian, A. M. Kuijpers-Jagtman, and J. W. Von den Hoff. 2010. Skin and oral mucosa
equivalents: construction and performance. Orthodontics & craniofacial research 13:11-20.
Noble, P. B., A. Sharma, P. K. McFawn, and H. W. Mitchell. 2005. Elastic properties of the
bronchial mucosa: epithelial unfolding and stretch in response to airway inflation. Journal of
applied physiology (Bethesda, Md. : 1985) 99:2061-2066.
Platt, A. M., and A. M. Mowat. 2008. Mucosal macrophages and the regulation of immune
responses in the intestine. Immunology letters 119:22-31.
10.
Turner, J. R. 2009. Intestinal mucosal barrier function in health and disease. Nature reviews.
Immunology 9:799-809.