Unit 3: Phonation Flashcards
Phonation
source of voice for speech, due to vibration of vocal folds which can be moved into or out of airstream
vocal folds
part of larynx. a “musculo-cartilaginous structure” at rostral end of trachea.
Larynx
Primary function is to protect the airway. It is the valve that keeps food and liquid out of the lungs. Has been hijacked for speech production.
It is suspended from the hyoid bone .
runs from the 3rd to 6th cervical vertebrae.
sits atop the last ring of the trachea. interior is lined with membranes.
44mm long male
36mm long female
hyoid bone
only bone in the body that is not connected to any other bones. larynx is suspended from it. It can move back and forth.
movement of bone can influence position of larynx. move in tandem with larynx
paired cartilage of larynx
Arytenoid - movement controls the size of the glottis** (hyaline - ossify) - key attachment point of each vocal fold
Corniculates - no real known function or role in phonation (elastic)
Cuneiforms - no real known function or role in phonation (elastic)
unpaired cartilage of larynx
Epiglottis - can fold down posteriorly to help protect airway during swallowing - NO phonation (elastic)
Thyroid Cartilage Lamina (hyaline - ossify)
Cricoid Cartilage - sits immediately on trachea (hyaline - ossify).
vocal folds/cords
bands of tissue where the membranous lining of the inside of the larynx sort of folds in.
- one vocal fold runs from each arytenoid to thyroid, inside each notch.
Thyrohyoid membrane
extends from the upper border of the thyroid cartilage to
Quadrangular membrane
runs from arytenoids to epiglottis/thyroid cartilage.
Lower free forms false vocal fold (ventricular fold)
upper margins are muscular = aryepiglottic folds
Cricothyroid membrane (or conus elasticus)
extends from the upper margin of the cricoid cartilage to attach to the back of the thyroid cartilage anteriorly and the arytenoid cartilage posteriorly.
Its upper free margin is the true vocal fold.
cricotracheal membrane
forms the connection of the larynx to the trachea
glottis
the space variable between the true vocal folds, 12-15mm long
extrinsic
means that these muscles have one attachment point in the structure (larynx) and another one somewhere else.
intrinsic
muscles entirely contained within the larynx
Bernoulli Principle
Given a constant volume flow of air or fluid, at a point of constriction there will be a decrease in pressure perpendicular to the flow and and increase in velocity of the flow.
Aerodynamic Myoelastic theory (ADMET)
Vocal folds closing again after an airstream blows them open
vocal/modal registers
Modal register - involves shortened somewhat folds vibrating in undulating pattern.
Pulse/Glottal Fry - The folds are slackened and air bubbles through but folds closed most of the time. You can hear individual bursts of air.
Falsetto - the folds are thinned and lengthened and tensed for high frequencies. vibrating at high rate.
Transglottal Pressure Drop
This needs to be 6 to 10cm of water (above atmospheris pressure below the vocal folds) for normal modal phonation.
variants of modal registers
Modal Phonation - Neutral glottis, inferior section never closes completely, but superior section does. Folds vibrate over full length, but not synchronously along length.
Breathy Phonation - Aryetinoids not pressed together, superior section never closes fully, noise due to turbulent airflow.
Creaky/pressed phonation - Aryetinoids pressed firmly together, folds more uniform along length and closure more abrupt.
Fundamental frequency
Frequency of vibration of the vocal folds. # of cycles the vocal folds go through per second. (we perceive this as pitch)
Controlled by the cricothyroids in conjunction with the thyrovocalis muscle.
asking a question requires increasing fundamental frequency even as pressure is dropping which requires laryngeal adjustments.
Laryngeal Development
Males and females have the similar length of vocal folds (and high fundamental frequency) until puberty in which male length spikes up.
