Physiology Of The Vocal Organ.
The Nervous System – Neurology
The nervous system is contained within the animal tube of the body. Its central organism is the spine and the brain. The nerves are fibers which run from the central organism to the different parts of the body. The controlling organ is the brain. The spin is the seat of the senses, the will, and all spiritual activities. The nerves are only the wires connecting the brain with the different parts of the body, especially through the muscles. According to the way in which the nerves affect parts of the muscles they are called motor, sensory or secretionary nerves.
There is another system of nerves called sympathetic nerves, having to do with the intenstines, etc.; but these belong to the vegetable tube and do not concern us.
The nerves consist of fibers and cells. The fibers consist of a white substance, the cells of a gray nerve substance. Just as the arteries branch out of some main channel, so do the nerves grow in bundles out of the bony tube of the spine, and divide into many fibers which, like telegraph wires, reach in all directions. Each muscle has its individual nerves with control it.
There are twelve pairs of brain-nerves, specifically motor and sensory nerves. They spread over the head, throat, chest and partly into the abdomen. These are the nerves of smell, sight, taste, hearing and secretion; and also the nerves which control the movements of the eyes, lips, tongue, palate, larynx, etc. Only those nerves which have to do directly or indirectly with the vocal organ, are of interest to the voice student.
These nerves spread within the hollow space between the nose and the palate and pharynx, as shown by Fig. 78.
At “aut” arises the tympanic nerve, which controls especially the sense of hearing, as shown in in Fig. 79.
All the nerves have one common origin, hence they operate together. The tympanic nerves has one branch running downward directly into the lingual nerve, “V.” The lingual nerve is the special nerve of speech. It runs directly into the hyo-glossus muscles and branches from there into the genio-glossus, against which the hyo-glossus braces itself to stretch the vocal chords.
This is a most significant fact. It points again to the great importance of the hyo-glossus muscles in the main agents of voice. Since the nerve of hearing branches into the nerves of the tongue, that is, into the nerves of speech, you can readily see that the nerves of hearing and nerves of speech are almost identical.
The ear conceives a tone. The tongue, or rather, the hyo-glossus executes the tone, being assisted by the muscles of the palate and larynx, which also have a common center with the other nerves.
This fact becomes still more significant when you examine Fig. 80,
where you can see how the laryngeal nerves again touch the hyo-glossus muscles and run directly over the hyoid bone into the larynx. The close relation between voice and health may also be observed in this illustration. You notice that the main nerve rises from the heart “AA” and the stomach “Pgs.” At the heart of the nerve shoots a special branch upward into the larynx. This in itself explains the emotional relations of the voice with the heart, which has to supply nervous force to the voice and stomach muscles as well as to its own. It shows how much they must depend upon each other. Suppose the vocal organ or, rather, the muscles which control the move the vocal organ are too weak to do this work, then they cannot contract; that is, they cannot respond to the demands of the nerves.
The consequence must be that the nerves of these muscles will lose strength and possibly become atrophied, which is the case with many stammereres and others with speech defects. In this case, surely the nerves of the heart and stomach are to some degree also affected. On the other hand, when the muscles into which these nerves enter are in a healthy state, the nerves will remain healthy also, assuring that the central organs of the heart, lungs and stomach are in a normally healthy condition. You can trace the nerves from the brain, their common center, to the particular parts which they control.
Fig. 81 gives a complete view of the brain as seen from below.
“H” shows the origin of the hyo-glossus nerve. “Gl” shows the nerves of the tongue and pharynx. “T” shows the palate nerves. All these nerves belong to the group of motor nerves; that is, these nerves move the muscles to which they are attached.
As a rule, muscles connect the bones of the body through the medium of a ligament or tendon. A muscle usually consists of three parts: an origin, body and head. By the origin is meant a bone that is firmly fixed. Out of this bone the muscle grows, while the other end or head is attached to a moveable bone. Muscles are formed into groups, several muscles help to perform the same office; for instance, when we take a step, several muscles unite to move the bones at the same instant. Each group of muscles is supplied with one or more nerves.
Dr. Foster, of London, England, in his interesting work, describes the inner workings of a muscle thus: “One should think of a muscle as containing many cells which lie beside one another like particles of powder. To each of these particles leads a thread from the central battery of the brain. The explosion of one of these particles contracts the muscle instantly, and it remains contracted until a part of the negative battery is exploded, when the muscle at once returns to its original relaxed position. If we try to force a muscle it refuses to work, because, as it seems, the positive and negative batteries neutralize each other, so that the muscle cannot work at all. After the particles are exploded, the muscle is tired or broken down. During rest the blood builds up new particles, and in this way a muscle is rebuilt and made stronger.”
Therefore, all ideas of force must be dismissed. But the theory of looseness and flabbiness, so often taught, is just as bad. In both cases the muscles refuse to work and become useless. If, however, we strengthen the muscles, there is no need to force them, for they will then do their work automatically.
Beside the motor nerves, there are nerves of the senses. They are called the “sensory” nerves. These nerves are especially the nerves of sight, taste, smelling, hearing and secretion.
The Sense Of Hearing.
The organ of hearing is divided into three parts. The outer part, or ear proper, conveys the tone or vibrations to the middle ear, or the tympanum, and thence to the inner ear, or labyrinth.
The external ear (Fig. 82).
Consists of cartilages, covered by facial skin. The cartilages are connected with the head by muscles, which occasionally are capable of moving the ear. This is supposed to be a survival from prehistoric time, when, it is claimed, men moved their ears as a horse does now.
The external ear conveys the sound waves to the ear canal (Fig. 83).
At the end of this canal is situated the tympanic membrane. This membrane resembles the membrane in a telephone, or the head of a drum, and transmits vibrations to the little ear bones.
The middle ear consists of the tympanic cavity, into which opens the Eustachian tube, connecting the ear with the pharynx of the throat. It also contains three bones which transmit the sound waves or any vibrations to the labyrinth and through it to the auricular nerve.
The three bones (Fig. 84), “a,” hammer, “b,” anvil, and “c,” stirrup, are controlled by means of special muscles.
The inner ear consists of the so-called labyrinth, which is divided into the “Fr” vestibule, “l” canal, “c” cochlea (Fig. 85).
From the organs of hearing, the nerves lead to the brain; vibrations originating in an instrument are conveyed through the air to the tympanic membrane, thence to the labyrinth and through it to the ear nerves. They cause certain sensation or produce certain effects in the brain, which we receive as words and tones, or if the vibrations are unsteady or irregular, as noises.
Recent researches assure us that there are no less than 60,000 fibers in the inner ear, each of which will respond to a different vibration, thus giving the human ear a scale of 60,000 different sounds, infinitely more than any musical system is likely ever to utilize.
Whether the sound is single, as in the human voice, or manifold, as in the case of an orchestra, the brain receives a certain impression. The pitch, the tone color, the dynamic changes from loud to soft, or vice versa, will affect us very much as a blue sky will make us feel good, while fog and rain will have the opposite effect. In music, for instance, a piece written in G major will impress us as joyful lively while one written in B flat minor will affect us as melancholy and sad. A change of key or a change from major to minor, even short harmonic changes in the same piece, will affect our feelings, changing joy and courage to sadness or despondency, etc. All this occurs because certain stimulations of the heart, lungs and vocal chords are being conveyed by the nerves of hearing to the brain.
When you consider the acuteness of our sense of hearing, its immediate effect on us all, you will all the more realize the importance of a good voice. Your success in life, the happiness of those around you, largely depends upon the quality of your voice.
The physiology of the vocal organ is now finished. In other lessons you will be taught the physiology of the breathing organ, for while the breath is absolutely necessary to the voice, it is an organ by itself and must be studied separately.
The primary object of the breathing organ is to supply the entire body with the necessary oxygen, and only in a secondary sense does the breathing organ function as a source of breath supply to the vocal organ.
Still later in the course, certain parts of the human body, especially the masticatory apparatus must be considered, because these particular parts interfere with the voice. My lessons aim to be, first of all, a positive process of building up, therefore I give you a progressive, positive work, explaining, as we go along, why such work is necessary and proving each point so that you can see for yourself why the work must be done in the way prescribed here.
There are conditions which interfere with the voice, but if you know what to do, you will not be tempted to try negative experiments. Yet for a full understanding of the matter of voice, even the negative side must be considered, and this side of the vocal question also will be made known to you in good time.