**Gray, SD. Cellular physiology of the vocal folds. The Otolaryngologic
Clinics of North America. V.30.
No. 4. pp 679-98. Aug 2000.
The vocal folds are made up of three major layers from deep to superficial:
1. The Vocalis Muscle (labeled above as the muscularis)
2. The Lamina Propria (really 3 layers: deep, intermediate, and superficial)
3. The epithelium or epithelial tissue
The vocalis muscle is by far the most viscous (harder to set into motion, vibration). This portion of the vocal folds is necessary to change the vibratory patterns of the entire system. Upon hard contraction, for example, the vocal folds become more viscous and a greater amount of air (from the respiratory system) is needed to set them into motion.
The Lamina Propria (made up of three layers) is a little more pliable than the vocalis muscle. This allows for more ease of vibration throughout the vocal fold.
The most superficial layer is the epithelium, or epithelial tissue (found throughout the entire body). The thin layer of tissue is the least viscous of the three major layers and, therefore, most easily set into motion or vibration.
These layers work together to create the vibratory characteristics of one's voice (along with the respiratory system, which provides the power supply). If these tissues are dry or dehydrated, it is possible that they loose their inherent vibratory characterisitcs, changing the voice.
The epithelial tissue found throughout the body is a thin layer of cells (seen to the left). This is a look at the tissue at the cellular level. It is important to remember that good hydration occurs at the cellular level.