Vol.96 No.7 contentsPRACTICA OTO-RHINO-LARYNGOLOGICA
Vol. 96 No.7 July 2003
Histology and Function of the Human
Vocal Fold Macula Flava
Kiminori Sato
(Kurume University School of Medicine)
Maculae flavae (MF) are located at the anterior and posterior ends of the human vocal fold mucosa (HVFM). Their histological structure is unique, but the role of MF in the HVFM has not been clarified. We have postulated that the MF may be related to the metabolism of extracellular matrices (EM) in the HVFM. This hypothesis is supported by the following morphologic results from our past studies.
Human MF are composed of dense masses of EM that are essential for the EM of the lamina propria in the HVFM. Dense EM in the human MF extend up to those in the HVFM. Ground substance among the fibers in the human MF is composed of abundant and dense hyaluronic acid, which is an important glycosaminoglycan in the HVFM. The cells are dense in the human MF. Many cells (Stellate cells) in the MF have marked morphologic differences from the conventional fibroblasts. They have well-developed intracellular organella and constantly synthesize EM. Newborns already have immature MF at the same sites as in the adult vocal fold. During infancy, the EM synthesized in the MF appear in the membranous portion of the vocal fold at different times to initiate the formation of the three-dimensional EM structure of the HVFM. The MF in newborn and infant vocal folds appears to be related to the growth and development of the HVFM. In aged human adults, age-related changes of cells and EM in the MF can be observed, and presumably affect the EM of the HVFM.
On the basis of the results of our past studies, the MF in the HVFM are postulated to be involved in the metabolism of EM, which are essential for the viscoelasticity of the HVFM. The MF is considered an important structure in growth, development and aging of the HVFM.
Key words : vocal fold, macula flava, larynx, extracellular matrix, stellate cell