A&P Exam 3 Physiology Flashcards
Vocal tract
Tube-like series of cavities beginning at vocal folds/larynx and ending at lips.
Articulators
Movable structures which directly form portion of the vocal tract wall, or are directly attached to wall.
What are the dual roles of the articulators?
- Alter shape of vocal tract, therefore changing filter characteristics of the tract.
- May create sources of vibrational energy at some point in the tract above the vocal folds (Ex: tongue can vibrate).
Source Filter Theory
Voicing is produced by the vocal folds and shaped into sounds by the vocal tract. Changes in the configuration of the tract result in changed resonant characteristics.
Resonant frequency
The frequency of sound to which the cavity most effectively responds. These resonant frequencies govern our vowels.
What are the articulators?
- Lips
- Mandible
- Tongue
- Soft Palate
- Teeth
- Hard Palate
How do the lips move to produce different sounds?
- Bilabial closure /p/
- Labiodental articulation /f/
- Lip rounding /w/
- Lip protrusion /u/
Biomechanical properties of the lips
- Mass: small relative to forces available
- Viscosity: measurable, but relatively small
- Elasticity: very large
- Muscle: fast twitch; capable of large amount of force
Lips can move very quickly
Movement of the lips
- Upper & lower lips move together for most speech tasks
- Greater movement of one lip is associated with less movement in the other (inversely related)
- Lower lip uses greater velocity & force; does most of the work in closure
- Highly adaptable
Aspects of jaw muscle activity
- Antagonistic jaw muscles (elevators vs. depressors) seldom co-contract during speech
- Influences movement of lips
- Tongue rides on jaw
- Influences overall size of oral cavity
Biomechanical properties of the jaw
- Large mass
- Issue of inertia of accelerating/decelerating jaw
- Jaw may accelerate at 100-200 cm/sec2
- But, the muscles are large and fast, and are able to counteract and control jaw inertia
Movement of the jaw
Range of jaw movement for speech is much less than total available range (more restricted than chewing). Jaw is never totally closed during speech.
Biomechanical properties of the tongue
- Mass: negligible in relation to muscle forces available
- Viscosity: negligible in relation to muscle forces available
- Is a muscular hydrostat (structure with constant volume and no internal skeleton)
Movements of the tongue
Include:
- tip elevation/depression
- deviation
- lateral margin relaxation
- narrowing
- central grooving
- protrusion/retraction
- posterior elevation
- body depression
What affects how quickly the tongue moves?
How far it needs to move (velocity of lingual movement directly related to distance to be traveled, readjusted in relation to durational constraints).
Biomechanical properties of the velum
Movement path is fairly consistent across speakers. Velocity is strongly affected by phonetic context (what you’re saying).
Why does the velum elevate more for high vowels than for low vowels?
2 Explanations:
- Mechanical linkage: velum is anatomically linked to the tongue by the palatoglossus, so the height of the tongue will influence the height of the velum
- Perceptual acceptability: differences in velar height don’t matter because a speaker can still be understood even if velum is slightly lower than it should be during a vowel production
Velar movement: levator veli palitini
High correlation between velar height and levator veli palitini activity
Velar movement: tensor veli palitini
Relatively inactive during speech; more active on swallow and to open eustachian tube.
Velar movement: musculus uvulae
One thought to shorten soft palate, but others feel it tenses palate to allow more effective elevation by levator.
Velar movement: palatoglossus
Natural antagonist to levator. May help lower palate when time constraints dictate fast lowering (but, also activated during elevation).
Velar movement: palatopharyngeus
May produce fine adjustments in velar height when velum is elevated; may be involved in pharyngeal adjustments.
Development of cortical motor control: gravity
Infant learns the relationship between sensation of moving reflexively against gravity when they see their own movements (Ex: hands in front of face).
Development of cortical motor control: Flexor-extensor balance
Infants start off mostly flexed, eventually shifting to extensor as they interact with the environment.
