speech science chapter 5
to what do the terms abduction and adduction refer? what muscles control these actions?
Abduction refers to the opening, or outward (lateral) movement, of the vocal folds. Adduction refers to the inward (medial) or closing movement. Muscles that function to adduct the vocal folds include the lateral cricoarytenoid, the transverse arytenoid, and the oblique arytenoid muscles. The only intrinsic muscle that functions to abduct the vocal folds is the posterior cricoarytenoid.
what factors regulate change in fundamental frequency?
Factors that contribute to fundamental frequency include contraction of the thyroarytenoid muscle, contraction of the cricothyroid muscle, lung pressure, the length of the vocal folds, the tension exerted upon the mass per unit length of the vocal folds, and stiffness of the vocal folds.
define fundamental frequency, provide its symbol, and give average values for adult men and women and children
Fundamental frequency is the lowest frequency which is produced by the oscillation of the whole of an object, as distinct from the harmonics of higher frequency. The average fundamental frequency for a man is 115 Hz; for women it is 215 Hz; and for children it can range from 220-243 Hz depending on the age and sex of the child.
define glottis, subglottis, and supraglottis
Glottis is the space that is formed between the abducted (open) vocal folds. The subglottis is the airway below the vocal folds. The supraglottis is the airway above the vocal folds.
how is intensity regulated?
Intensity is regulated by lung pressure.
what is the contribution of lung pressure to the control of fundamental frequency?
Lung pressure may affect the amplitude of lateral movement of the vocal folds. The greater the lung pressure, the greater the vibrational amplitude, or lateral stretch of the vocal folds. This stretch results in a dynamic elongation of the vocal folds. The resulting transitory increase in the strain of the vocal folds would be expected to increase tissue stress, which would increase elastic recoil force, and so the vocal folds would snap back faster, raising the fundamental frequency.
define reinke's space
Reinke's space is another term for the superficial layer of the lamina propria.
describe the Bernoulli effect
The Bernoulli effect is an expression of the conservation of energy for a moving fluid. The Bernoulli effect has a critical role in vocal fold vibration and, hence, in voice production. The Bernoulli effect tells us that the faster the velocity results in lower pressure, thus producing a net upward force. Also, the Bernoulli effect tells us that fluid must flow faster in a narrower region of a tube.
describe the body-cover mechanical model of the vocal folds
The body-cover model groups the muscle and deep layer of lamina propria together, and the remainder of the lamina propria is grouped in turn with the epithelium as the cover layer.
what types of movements are made by the cricoarytenoid joints and what is the result of those movements?
The cricoarytenoid joints allow the arytenoid cartilages to rock and glide, enabling the vocal folds to abduct and adduct. Due to their role in opening and closing the vocal folds, these joints play a central role in the preservation of the airway for breathing as well as in vocal fold movement for phonation.
what is the function of the cricothryoid joint, and what effect does movement of the joint have on the vocal folds?
The cricothyroid joint regulates the angle of the thyroid cartilage with respect to the cricoid cartilage by rotating the thyroid cartilage forward and downward around the axis of the cricothyroid joints. The cricothyroid joint helps elongate the vocal folds which plays a role in the tension of the vocal folds. Tension of the vocal folds regulates fundamental frequency and contributes to intensity control.
describe the three-layer mechanical model of the vocal folds
The five histologic layers can be reclassified into three mechanical layers, consisting of the epithelium and Reinke's space (referred to as the mucosa), the transition (vocal ligament), and the body (thyroarytenoid muscle).
describe a cycle of vocal fold vibration using the updated myoelastic-aerodynamic theory. importantly, include the contribution of the physical properties of the vocal folds and the aerodynamic forces
The myoelastic-aerodynamic theory identifies the self-oscillating nature of the vocal folds. The external driving source identified in the myoelastic-aerodynamic theory is the airflow from the lungs. This theory emphasizes that vocal fold vibration is a passive event that results from an interaction or coupling of the glottal opening, the physical properties of the vocal folds, and the lung pressure. Vocal fold vibration begins when the arytenoid cartilages rock inward to adduct the vocal folds lightly, in this way closing the glottis partially or completely. As the thoracic cavity is compressed to exhale, the lung pressure increases below the glottis as the airflow meets the resistance of the closed vocal folds. The increased lung pressure pushes against the pliable and elastic vocal folds. When the lung pressure is great enough to overcome vocal fold resistance, the folds are pushed laterally to open the glottis. When the glottis opens, airflow commences. The lung pressure is greater than the pressure immediately above the glottis, causing that fluid flows from greater pressure to lesser pressure, the airflow is drawn upward through the vocal folds. Then the lower border of the vocal folds is returning to midline, causing a lowering of the transglottal pressure and an inward pull of the lower margin of the vocal folds. Then the upper border of the vocal folds returns to midline and full contact of the vocal folds is established.
identify the three layers of the lamina propria and describe their composition
The outermost (or most superficial layer) of the lamina propria is the epithelium. The epithelium is very thin and contains stratified squamous-type cells. The epithelium contains three layers. The most superficial layer of the lamina propria is composed of loosely arranged elastin fibers and a cellular matrix. The consistency of this superficial layer is like gelatin. It is often called Reinke's space. The intermediate layer of the lamina propria is also composed of elastin fibers, but these are more densely distributed and interwoven and organized to lie parallel to the free edge of the vocal folds. Some collagen fibers are also present in this layer. Collagen is often likened to thick cotton threads. The deep layer of the lamina propria is composed heavily of collagen fibers which are tightly packed and lie parallel to the length of the vocal folds. Proceeding from superficial to deep, the layers of the vocal folds gradually become increasingly stiff.
describe the 3 functions of the larynx
The three functions of the larynx include phonation, protection of the lungs from foreign bodies, and stabilization of the upper body during certain maneuvers, such as lifting a heavy object, running upstairs, and "pushing" for defecation and childbirth.
identify the three paired and three unpaired laryngeal cartilages
The three paired laryngeal cartilages include the arytenoids, corniculate, and cuneiform. The unpaired laryngeal cartilages include the cricoid, thyroid, and epiglottis.
define voice quality
Voice quality is a perceptual attribute that describes the sound of the voice beyond its pitch and loudness.
crepitus
a crackling or grating sound usually of bones-a good thing in the larynx
the vocal folds converts the aerodynamic energy generated by the lungs into what kind of energy?
acoustic energy in the form of sound waves
extrinsic muscles serve to do what?
adjust the overall position of the larynx within the neck and help stabilize the laryngeal position, particular so that the intrinsic muscles can exert their forces
the extrinsic muscles of the larynx are
all infrahyoid muscles ("below" the hyoid), which include the sternothyroid, sternohyoid, and the thyrohyoid muslces
extrinsic muscles extend from a laryngeal cartilage to
an external point of attachment
What are the paired cartilages of the larynx?
arytenoid, corniculate, cuneiform
what cartilages are composed of hyaline cartilage?
cricoid, thyroid, and most arytenoid cartilages
Valsalva maneuver
forcible exhalation against a closed glottis, resulting in increased intrathoracic pressure
what do the quadrangular membrane and aryepiglottic folds do?
help protect the airway from saliva and food
the fibroelastic membrane is covered by a mucous membrane which forms a wet and relatively smooth lining of the cavity that does what?
helps to maximize its aerodynamic properties
what is the only bone in the body that does not articulate directly with another bone?
hyoid bone
where are the vocal folds housed?
in the larynx
muscles of the larynx are divided into what 2 categories?
intrinsic and extrinsic
average length and diameter of women's larynx
length=36 mm diameter=41 mm
average length and diameter of men's larynx
length=44 mm diameter=43 mm
what do the suprahyoid muscles do?
move and stabilize the mobile hyoid bone
suprahyoid muscles
muscles that attach from the hyoid bone to structures above it, these include: the stylohyoid, mylohyoid, geniohyoid, and digastric muscles
does elastic cartilage ossify?
no
adduction
refers to the inward (medial) or closing movement
abduction
refers to the opening, or outward (lateral) movement, of the vocal folds
the outward movement during inspiration serves to widen the lumen (opening) to decrease
resistance to the airflow and ease inhalation
what is the vestibule referred to?
supraglottic space
which cartilages are composed of elastic cartilage?
the epiglottis and corniculate cartilages and a portion of the arytenoid cartilages
the ventricular folds are also called what?
the false vocal folds
phonation
the generation of sound by means of vocal fold vibration
what is the space between the ventricular vocal folds and the true vocal folds called?
the laryngeal ventricle
muscles that adduct the vocal folds include
the lateral cricoarytenoid, the transverse arytenoid, and the oblique arytenoid muscles
what intrinsic muscle functions to abduct the vocal folds?
the posterior cricoarytenoid
what is the muscle that abducts the vocal folds?
the posterior cricoarytenoid
what do the extrinsic ligaments consist of ?
the thyrohyoid membrane, the cricothyroid membrane, and the theyroepiglottic, hyoepiglottic, and cricotracheal ligaments
what is categorized as a relaxer of the vocal folds?
the thyromuscularis
2 muscles considered tensors of the vocal folds
the thyrovocalis and the cricothryoid muscles
what is the vestibule?
the uppermost cavity of the larynx
the uppermost border of the conus elastics compromises what
the vocal ligament
intrinsic muscles are
those that interconnect the laryngeal cartilages
phonotrauma
those voice patterns leading to traumatic tissue changes of the vocal folds
What are the unpaired cartilages of the larynx?
thyroid, cricoid, epiglottis
what is the role of the hyoid bone?
to support the larynx and to connect tongue movement to laryngeal and supra glottal movement and it acts as an anchor point for numerous muscles
the intrinsic muscles are responsible for what?
vocal fold movement and fine motor control required for regulation of fo, intensity and tonal quality of voice
does hyaline cartilage ossify?
yes
main functions of the larynx:
1. phonation 2. protect the lungs from foreign bodies 3. stabilize the upper body during certain maneuvers
how many paired cartilages comprise the larynx?
3
how many unpaired cartilages comprise the larynx?
3
