Caitlin Craig Malde 4

What is the difference between intrinsic and extrinsic laryngeal muscles?  What are their functions? Intrinsic laryngeal muscles are connect on both sides within the larynx and are responsible for the delicate movements within the larynx. Extrinsic muscles connect to the larynx from outside and move the larynx as a whole up and down in the neck. 

Describe the cartilages of the larynx.  Include information about structure, size, function.
1. The cricoid cartilage-forms the base of the larynx and sits at the top of the trachea- sometimes called the "ring" cartilage. The diameter of the space is about 9-17 millimeters for women and 11-21 millimeters for men. When at rest the bottom of the cartilage is parallel to the floor. The back ring is also taller than the front. 
2. The thyroid cartilage-forms the front of the larynx and anchors the front of the vocal folds. It is the part of the larynx known as the Adam's apple. It is open at the back and extends about 2/3 of the way around of the sides of the larynx. There are two pairs of horns at the back of the thyroid cartilage-the superior horns which extend upward connecting through ligaments to the hyoid bone, and the inferior horns which extend downward, connecting through a joint to a place on each side of the cricoid cartilage near the back. These joints allow the thyroid cartilage to rock forward in relation to the cricoid cartilage. 
3. The arytenoid cartilages-are at the back of the larynx and anchors the back of the vocal folds. They perch atop the back of the criocoid cartilage connected by flexible joints that allow them to swivel and slide. Each of the arytenoid cartilages have three processes: one on top and two on the bottom. They are shaped roughly like triangles standing on edge. At the processes the triangles are thin and then thicker in the middle. The two processes at the base of each arytenoid cartilge are called the vocal process and the muscular process. When the laryx is at rest, the vocal processes point forward toward the front of the thyroid cartilage while the muscular processes point toward the sides of the cricoid cartilage.
4. The epiglottis cartilage-is at the top of the larynx. It is shaped like a two-dimensional teardrop with the point pointing downward. This point connects to the center of the thyroid cartilage on the inside. The epiglottis plays an essential role in survival: the muscles around it pull it down over the glottis to prevent food and liquid from entering the trachea.
What is cartilage? A tough, elastic tissue with a distinct shape like bone but more flexible.

What is ligament? A short, flexible, tough fibrous type of connective tissue that connects bone to bone, bone to cartilage or cartilage to cartilage.

What is muscle origin? The point of attachment of a muscle that remains relatively fixed during contraction.

What is muscle insertion? The point of attachment of a muscle that moves most during contraction.

What is dynamic equilibrium? When opposing muscles are working 

What is muscle antagonism? When opposing muscles are working against each other: both are contracting. a.k.a. co-contraction.

What are opposing muscles? Muscles that work in opposite directions. Biceps and triceps are opposing muscles: one bends the elbow, and one straightens the elbow.

What are paired muscles? Muscles that occur on both sides of the body, one the mirror image of the other.

What is stabilized physiological tremor rate? The rate of vibration innate to the body that occurs when muscle antagonism is sustained.

Describe the following muscles (location and function)
1.  posterior cricoarytenoid- open the glottis or VF's wide for a singing breath.
2.  lateral cricoarytenoid-partially close the glottis. Close the VF's for phonation.
3.  transverse arytenoid-complete the closure of the glottis. Closes the VF's for phonation.
4.  oblique arytenoid-complete the closure of the glottis. Closes the VF's for phonation.

What are the two parts of the Thyroarytenoid muscle?  What are their functions? Both pairs connect the inner surface of the thyroid cartilage to the arytenoid cartilages. Each side is divided into two parts. The fibers of the parts are continuous with one another, yet act independently. The two parts are called the vocalis muscle and the external thyroarytenoid muscle. The vocalis muscles are the primary vibrating bodies of the vocal fold and snuggle up to the vocal ligaments on either side of the glottis. When they contract, they increase the tension of the VF's. The external thyroarytenoid muscles are on the outside of the vocalis muscles. When they contract, they make the vf's shorter and thicker. 

What are the two parts of the Cricothyroid muscle?  What are their functions?  What are their attachments? The paired cricothyroid muscles arise from the sides of the cricoid cartilage at the front. From there, they extend back at an oblique angle to attach to the bottom of the thyroid cartilage at the sides. Each side has two parts or bellies. When they contract they rock the thyroid cartilage forward at its joints with the cricoid cartilage. They bring the cricoid cartilage and the thyroid cartilage closer together at the front and farther apart at the back. This action stretches the vocal folds, making them longer and thinner. 

How is pitch determined? The book says that pitch is determined by the rate of vibration in a musical instrument. The faster the vibration the higher the pitch. In singing the rate of vibration depends on the length, thickness, and tension of the vf's. 

What happens as we descend in pitch? Our VF's lengthen and become thinner. 

Summarize the activities of the 3 laryngeal muscles responsible for pitch.We discussed in class that this part in the book was incorrect, because it is a lot more complicated than that.

Define register.  (What happens at the laryngeal level?) Register is a series of tones that have the same vocal production. Pitches produced with thick vf's will sound different from the same pitches produced with thin vf's, even when they are sung by the same singer.

Name and describe the 4 registers of the voice.  (Please include the subdivisions of modal.)
1. Modal voice- most singing occurs here where the thyroarytenoid and the cricothyroid muscles are active to some degree (working in dynamic equilibrium). Throughout most of this singing range there is some good tension in the vf's--just enough to do the work, not enough to strain. The modal voice is split into two subcategories: chest voice, and head voice. Chest voice (heavy) is when the action of the thyroarytenoids predominates, and the vf's are thick. Typically this register is associated with a low pitch range. When the action of the cricothyroid muscles predominates, the vf's are stretched thin, producing a register commonly known as head voice (light). This register is commonly associated with a high pitch range. These two registers can be mixed to create the mixed or middle voice register.
2. Falsetto/flute- this register is the point in range where the thyroarytenoid muscles release completely is called falsetto in men and flute in women. The pitch is adjusted within this register by the cricothyroid muscles alone.
3. Whistle- When the cricothyroids have reached their maximun contraction, the back portions of the vf's are damped, that is, they are kept from vibrating. This effectively shortens the length of the vibrating edge,like a violin string is shortened when a finger presses it against the fingerboard. This register is most commonly heard in women's voices. 
4. Glottal fry- when the cricothyroid is disengaged completely, and vf's are thick and released and the air that passes through them produces a rattling sound very different from other phonation. This register is commonly used in popular styles. 

How does heavy vs light differ from loud vs soft? Because the vf's are thickened in chest voice, we perceive the sound to be heavy. Because the vf's are thinned in head voice, we perceive the sound to be light. these terms heavy and light are independent from loud and soft. Though tones produced with thick vf's have a robust color, they may be soft and vice versa.

In classical singing, we blend the actions of the TA and CT using dynamic equilibrium.

What are the 3 possible types of onset/offset.  Describe them. Glottal- In onset, vibration is delayed momentarily because the folds are already closed when the air flow reaches them. It takes a moment for the air pressure beneath the glottis to force the vf's open and set them into vibration. When they do start vibrating there is an audible click in the sound. During offset, the vf's close tightly and cease vibration before the air has stopped flowing from the lungs, making anabrupt, rather forceful end to the sound almost like a grunt. 
Aspirate- In onset, the phonation is also delayed momentarily. The air flow reaches the glottis before it closes. Air escapes before the vf's come into vibration, sounding breathy. During aspirate offset, the vf's separate while air continues to flow from the lungs, sounding like a final [h] or a sigh. 
Balanced- In onset, the air flowing from the lungs meets the glottis just as it is closing and sets the vocal folds into vibration immediately. During offset, the vf's separate just as the air ceases to flow from the lungs. 

How do the vocal folds come into vibration? The interaction of the vf's with the expiratory breath flow causes the vibrations of phonation. When the vf's are abbducted by the the intrinsic muscles,  breath pressure builds up beneath the glottis. The pressure forces the vf's apart and a puff of breath escapes.The vf's immediately come back together because of 2 natural laws: the elastic recoil of muscles and the bernoulli principle. Elastic recoil is the tendency of anatomical structures to return to the state they were in before being acted upon. As soon as the force of the breath pressure is alleviated, the elastic muscles of the vf's spring back to the shape they were making to produce the pitch. The Bernoulli principle is the tendency of gasses and liquids to flow faster through narrow spaces. When air molecules move through a narrow space, they also speed up, creating an area of low pressure in that space. If the sides of the space are flexible, like the vf's they tend to be drawn closer together 

What causes a breathy sound? Resonance and phonation can both cause breathy sound. The larynx will produce a breathy sound when the vf's are either closed too loosely or the space between the arytenoids is left open. Breathy tone is common among young singers who usually grow out of it as they mature. 

What causes a strident sound? It can be caused by resonance choices. When caused in the larynx, a strident tone is often the result of heavy vocal production. (i.e. carrying chest voice up too high). This causes build up of unwanted tension of the vf's in order to raise the pitch-making the tone harsh.

What causes a tight sound? A tight sound is generally caused by the layrngeal muscles working too hard to close the glottis. The closure should be complete, yet gentle. It can result from excess tension in the neck or the walls of the throat. 

What does the larynx have to do with dynamics? Loudness and softness are regulated by the speed of the breath flow and the reaction of the vf's to that flow. When we sing softy, we release air slowly. When we wish to sing loudly we release air quickly. The intrinsic muscles react to the resulting difference in air pressure, subtly adjusting the degree of closure of the vf's. 

How can intonation be fixed? 1. it is easy to stay in tune when singing within a narrow range. The wider the compass of the phrase the more difficult intonation becomes. Shifting back and forth between heavy and light registers will often make a singer sound out of tune because the overtones are so different.
2. Registration has another effect on intonation. If the heavy production is brought high into the range, the muscles become increasingly strained. It is likely that the singer will sing flat because of the effort involved in sustaining that rate of contraction. If light registration is brought low into the range, sometimes singers sing sharp.
3. Singers who are used to singing with a certain registration in a part of their range may go sharp or flat when they try to sing in a different register until the mechanism and ear adjust to the new color. 
4. Resonance also plays a part in intonation.

What causes vibrato? It is a naturally occurring part of the voice. It occurs whenever the opposing muscles of the larynx are working in balance with enough force to create the stabilized physiological tremor rate innate in the body. 

How can vibrato be controlled? It can be controlled or suppressed for effect depending on the style being sung. It can be cultivated or repressed, but whenit is manufactured it always sounds unnatural (too slow, too wide, or simply uneven). Sometimes faulty vibrato is caused by too much vocal effort, or an imbalance of breath flow. For effortless vibrato the body must be in balance. The neck must be released and the extrinsic laryngeal muscles that connect to the larynx and regulate its movement as a whole must be in balance so that the larynx is stable. In addition, the breath flow must be in balance with phonation and there must be just the right amount of antagonistic force in the muscles of the larynx. 

What are nodules and how can they be prevented? Nodes are calluses on the epithelium membrane covering the vocal folds. They are treated with vocal therapy. Singing when dehydrated, tired, or stressed is a bad idea. Talking too loud, in smoky environments may also cause damage. Pushing beyond what feels natural can lead to serious conditions. Pay attention to your larynx in the context of your whole body. If you suspect you are suffering from a vocal injury stop singing, and see a voice care specialist.