Types of tracheal submucosal glands: implications of literature controversy

Abstract

In what concerns the morphological description of tissues and organs there are some conceptual discrepancies in the classical literature used as the knowledge foundation of basic sciences in health and medical colleges. Such controversies may create conflicts and jeopardize the relationship of trust between students and faculty members. This paper compares basic histology books and atlases with respect to the main information on tracheal subucosal glands. We analyzed 23 books and 21 atlases (from which 17 were virtual atlases), focusing information regarding presence and classification of tracheal submucosal glands. All references agreed that exocrine glands were present in the tracheal submucosa, however we found controversy about its types: presence of “seromucous glands” were referred by 39.1% of the references; presence of “mucous and serous glands”, by 26.1%; “mucous glands with serous components”, 17.4%; presence of both “mucous” and “seromucous”, 4.3%; “mixed glands” 4.3%; mucous, serous and mixed glands, 2.2%; mucous only, 2.2%; serous only, 2.2%. No information on gland type could be found in 2.2% of the references.CONCLUSIONThere is no consensus in what concerns the classification of the glands present in the trachea submucosa. The lack of consistence in basic information and terms may be a source of problems in standardization of histological terminology. Furthermore, such controversy may affect student's confidence in the subject and the staff, since the reliability of the theoretical basic knowledge is questioned.