Ultrastructure of the Mucous Membrane of the Human Newborn Vocal Folds.

Abstract

This study was carried out to determine the ultrastructure of the mucous membrane of vocal folds of human newborns. Excised larynges of newborns were observed with a transmission electron microscope.The results obtained are summarized as follows: 1) The epithelium of the edge of the vocal folds consisted of stratified squamous epithelium. It was thin but numerous desmosomes showed firm attachment between cells.2)The basement membrane zone had the same structure as that of adults.3) The lamina propria of the vocal fold mucosa was loose in structure and there was no vocal ligament. 4) Fibroblasts were sparse and in the resting phase.5) Collagenous and elastic fibers were sparse in the lamina propria. Structures of the collagenous fibers were mature but those of elastic fibers, were immature morphologically. 6) Ground substance was abundant in the lamina propria. 7) The newborn vocal fold mucosa lacked not only a vocal ligament but also adequate viscoelasticity for vibration.

Expression and Distribution of CD44 and Hyaluronic Acid in Human Vocal Fold Mucosa

“…20 -23 The extracellular matrix structure of the newborn vocal fold mucosa is incomplete; consequently, viscoelastic properties of the lamina propria of the vocal fold mucosa are postulated to not be suitable for vibration. 22 ,23 Furthermore, the morphological characteristics of the newborn vocal fold stellate cells are not completely the same as those of adults.f Newborn vocal fold stellate cells are immature and possess some features of mesenchymal cellsf…”

Vitamin A-Storing Stellate Cells in the Human Newborn Vocal Fold

“…On the other hand, the human newborn vocal fold mucosa is immature and does not have a layered structure. [6][7][8]14 The extracellular matrix structure of the newborn vocal fold mucosa is immature; consequently, the viscoelastic properties of the lamina propria of the vocal fold mucosa may not be suitable for vibration. "…”

Establishment of a Normative Pediatric Acoustic Database

“…It is well established that the vocal folds undergo histologic changes from birth to adulthood, where the vocal fold matures from a monolayer to a trilayer structure. [18][19][20][21] It is assumed that girls and boys undergo the same vocal fold maturation development from a histologic standpoint in terms of developing a 3-layered structure; yet it is still unclear what causes the changes in frequency seen between boys and girls prior to adulthood. Most likely, differences occur because of a combination of factors such as variation in vocal fold length and sex-specific morphologic and metabolic changes dependent on hormonal influences.…”

“…Most likely, differences occur because of a combination of factors such as variation in vocal fold length and sex-specific morphologic and metabolic changes dependent on hormonal influences. 8,11,[17][18][19][20][21] We are hopeful that new technological advances, such as noninvasive high-resolution imaging, will help aid in answering this question, which has up to now been dependent on postmortem tissue specimens, which are difficult to obtain in the pediatric population.…”