Nasal cavity, paranasal sinuses, nasopharynx
General
Histology
Author: Nat Pernick, M.D.
Last author update: 1 November 2004
Last staff update: 11 July 2020
Copyright: 2004-2023, PathologyOutlines.com, Inc.
PubMed Search: Normal histology nasal cavity[TI]
Table of Contents
Definition / generalCite this page: Pernick N. Histology. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/nasalnormalhistology.html. Accessed March 24th, 2023.
Definition / general
Nasal cavity
Nasopharynx
Paranasal sinuses
- Lined by stratified squamous and respiratory type pseudostratified columnar epithelium, separated by transitional epithelium in some places
- Respiratory mucosa (also called Schneiderian membrane) may contain goblet cells; may undergo squamous metaplasia
- Superior third of nasal septum, superior turbinate and cribriform plate are covered with thinner olfactory mucosa, usually patchy in adults, which has neuroendocrine features
- Seromucinous glands (resembling salivary glands) are present in submucosa, numerous near eustachian tube opening of nasopharynx, may undergo oncocytic metaplasia with increasing age
- Normally no lymphoid tissue
Nasopharynx
- Lined by stratified squamous epithelium (inferior anterior and posterior walls and anterior lateral walls) and respiratory type epithelium (around nasal choanae and roof of posterior wall); remaining areas have mixtures of squamous and respiratory or intermediate epithelium (also called transitional although it does not resemble urothelium ultrastructurally)
- Intermediate epithelium is usually concentrated as a wavy ring at junction of nasopharynx and oropharynx
- Seromucinous glands may undergo oncocytic metaplasia and rarely form a mass or obstruct eustachian tube
- Abundant lymphoid tissue present, particularly at rim of eustachian tube opening (Gerlach tonsil); functionally equivalent to that of GI tract or mucosal associated lymphoid tissue (MALT)
Paranasal sinuses
- Mucosa is continuous with nasal cavity and identical (respiratory type epithelium) but thinner and with fewer goblet cells and seromucinous glands
- Normally no lymphoid tissue
