1.1. Physiological basis of singing
Structure and functioning of the human vocal tract during phonation make the physiological basis of singing. Human phonetic system is a complex anatomical notion including the respiratory system and the respiratory tract in its whole. The major function of this system is gas exchange that is a base for all vital functions of a human body.
Phylogenesis has let the muscular systems of the upper respiratory section execute the innate function of defense. This function usually works in extreme conditions when the living body gets into an environment unfavourable for living. Pharyngoesophageal sphincter is constrcted automatically to protect the interior respiratory organs from harmful gases.
Due to a further development and perfection of human biological system, the organs of the human body acquire one more socally important function present in speaking and singing, they help to vocalize.
The vocalizing system can be represented as a complex system consisting of 3 parts: the respiratory system, the larynx and the articulatory apparatus. Modern physiology and phoniatrics treat these parts as three subsystems:
- energy system (lungs, bronchi, trachea, inspiatory and expiratory system);
- generating system (larynx with vocal cords)
- system of resonators (epigottal articulatory system consisting of aditus larynges, of pharynx, mouth and nasal cavity, and paranasal sinuses)
All the three parts of the system work consistently and are very well coordinated due to an integrated enervation that is controlled by higher nervous activity (of the cerebral cortex).
Every part of the vocalizing system is connected with others: if the respiratory system is active, it will impact the activity of articulatory organs and vice versa. To use this interaction, it is necessary to deeply understand the biological mechanisms of phonation in singing, depending from the tessitura, the type of vowel, dynamics and emotional picture of the artistic side in a musical artwork.
When the sound goes through the epiglottal (upper-laryngeal) system of resonance and articulation, it is acoustically reworked with help of some kind of philter. That's why a sound produced by a singer, when it comes out from his mouth, is so different from its source in the vocal cords.