1. CSD 2230 HUMAN COMMUNICATION DISORDERS
Topic 3
Introductory Anatomy and Physiology of the Speech, Voice and Auditory System
The Laryngeal and Articulatory/Resonating Systems
Speech Production Process
In this unit, we’ll be identifying the major structures of the laryngeal system (commonly referred to as the voice box), the articulatory/resonating system (throat, mouth, nasal cavities), and the physiology of speech sound production.

2. The Laryngeal System Functions: Biological Speech
Prevents foreign objects from entering the trachea
Coughing
Speech
voicing
The laryngeal system
The major component is, of course, the larynx (don’t say “lar-nix”).
Like the respiratory system, the larynx has some important biological functions in addition to its job as the sound generator for speech production.
Biological functions included:
1. On the upper end of the larynx, where the larynx connects to the trachea is a laryngeal structure known as the Epiglottis. This structure covers the entrance of the trachea to keep foreign objects from entering the lungs.
2. The larynx can trap air from the lungs, build up pressure, to allow for forceful expulsion. Known as a cough. Works to expel foreign objects from the lower airways.

3. Structural Support Hyoid bone Thyroid cartilage Cricoid cartilage
Arytenoid cartilages
Epiglottis
Structural support of the laryngeal system
1. Hyoid bone: this is a horseshoe-shaped bone got connected with any other bone in the body. Lies horizontally in the neck at the level of C3. The larynx is suspended from the hyoid via the thyrohyoid membrane. It also is a major point of attachment for muscles of the larynx and tongue.
2. The rest of the structures of the larynx are cartilage pieces. They include:
a. Thyroid cartilage: the largest piece and forms the anterior and lateral walls of the larynx. This is the piece which forms the Adam’s apple in the front of the throat.
b. Cricoid cartilage: inferior to the thyroid cartilage. Sits right above the first ring of the trachea.
c. Arytenoid cartilages: there is a pair of these on the posterior and superior border of the cricoid. The vocal folds are attached, at one end, to the arytenoids.
d. Epiglottis: large leaf-shaped structure attached to the thyroid which helps prevent objects from entering the trachea. Covers the opening of the trachea during swallowing.

4. Structural Support
Here’s another view of the larynx from the front (anterior) view. Point out the thyrohyoid membrane. Remember this is what suspends the thyroid cartilage to the hyoid bone.

5. Vocal Folds Points of attachment: Thyroid cartilage
Artenoid cartilages
1. Vocal folds: don’t call them cords. Viewed from above (from the throat looking down) the folds are ivory colored bands of tissue. They are attached at one end to the thyroid cartilage, and the other end to the two arytenoids.

6. Vocal Folds and Their Points of Attachment
Thyroid
Arytenoid
Glottis
CD ROM demo and 12.05
Point out points of attachment again

7. Muscles of the Larynx
A number of muscles that assist in the movement of the vocal folds and larynx
Three groups
1. Laryngeal Musculature: there are a lot of muscles that assist the movement of the vocal folds and larynx. These muscles are usually divided into three groups

8. Extrinsic Laryngeal Muscles
These muscles have one point of attachment on some structure of the larynx and another point of attachment on structure outside the larynx
a. The extrinsic laryngeal muscles: these muscles have one point of attachment on some structure of the larynx and the other point of attachment on structures outside the larynx

9. Intrinsic Muscles of the Larynx
These muscles have both points of attachment within the larynx
Muscles of abduction
Muscles of adduction
Tensor muscles
a. The intrinsic muscles: have both points of attachment within the larynx. These muscles are primarily responsible for phonation and modification of pitch and loudness of the voice. These intrinsic muscles are further divided into the following groups:
i. Muscles that separate the vocal folds: we call this “abduction”
ii. Muscles that bring the folds together: we call this “adduction”
iii. Muscles that tense the vocal folds

10. Supplemental Muscles of the Larynx
These muscles have one point of attachment on the hyoid bone and course either above or below
Suprahyoid
Work to raise the larynx
Infrahyoid
Work to drop the larynx
a. The supplemental muscles: have one point of attachment on the hyoid bone and course either above (suprahyoid) the hyoid or below (infrahyoid) the hyoid bone. Generally, the suprahyoid muscles assist in raising the larynx. The infrahyoid muscles depress or drop the larynx.

11. Some Major Laryngeal Muscles
Posterior cricoarytenoid
Intrinsic laryngeal muscle
Only muscle that abducts the fold
Some of the more important muscles of the laryngeal system:
1. Posterior cricoarytenoid: this is an intrinsic laryngeal muscle and is the only muscle that abducts or separates the folds

12. Some Major Laryngeal Muscles
Lateral cricoarytenoid and Interarytenoids
Intrinsic laryngeal muscles
muscles that adduct the folds
Some of the more important muscles of the laryngeal system:
1. Lateral cricoarytenoid and interarytenoids: both are intrinsic muscles of the larynx and are the muscles responsible to close the folds, adduction.

13. Some Major Laryngeal Muscles
Thyroarytenoid and Cricothyriod
Intrinsic laryngeal muscles
muscles that tense the larynx
Some of the more important muscles of the laryngeal system:
thyroarytenoid and cricothyroids: intrinsic laryngeal muscles that tense the larynx to change pitch

14. The Articulatory/Resonating System
Divisions of the vocal tract
The pharyngeal cavity
The oral cavity
The nasal cavity
The articulatory/resonating System:
Collectively, we call the structures of this system the “vocal tract” which we view as a resonant acoustic tube where are the sounds of speech are formed. The three major divisions of the vocal tract included
1. Pharyngeal cavity: the neck
2. The oral cavity: the mouth
3. The nasal cavity: the nose

15. The Skull Structural support system
The structural support of the artic/reson system is the skull. Major landmarks related to the aric/reson system include the maxilla, the mandible, the zygomatic bone and arch, the mastoid, the styloid process, and the temporomandibular joint.

16. Major Landmarks of the Skull for Speech
The structural support of the artic/reson system is the skull. Major landmarks related to the aric/reson system include the maxilla, the mandible, the zygomatic bone and arch, the mastoid, the styloid process, and the temporomandibular joint.
Major landmarks include:
Maxilla, mandible, zygomatic bone and arch, temporomandibular joint, temporal bone, and mastoid

17. Important Structures of the Vocal Tract
Teeth
16 pairs for 32 total
Imbedded within the alveolar processes of the mandible and maxilla
Think about /f/ and /th/
Important structures for speech production:
The teeth: adults have normally 32 teeth (16 pairs on each side). The teeth are imbedded within the alveolar processes of the mandible and the maxilla. Several speech sounds are made by pressing the tongue or the lips against the upper teeth. Think about /f/ and /th/.

18. Important Structures of the vocal Tract
Hard palate
Maxilla
Think about /t/ and /s/
Important structures for speech production:
1. The bony hard palate: made by the horizontal bones of the maxilla. This is the anterior (front) 2/3 of the roof of the mouth. Many sounds are made by the tongue touching the hard palate to completely occlude the oral cavity, or to create a point of constriction. Think about /t/ and /s/.

19. Important Structures of the Vocal Tract
Velum
Soft tissue
Think about /k/ and /g/
Biological purpose of the velum is to separate the oral cavity from the nasal cavity
CD ROM demos
11.07 and 11.08
Important structures for speech production:
1. 1. The velum or soft palate: this is the back 1/3 of the palate and is made of soft tissue. Sounds like /k/ and /g/ are made by pushing the back of the tongue against the soft palate, blocking the air leaving the lungs at this point for a brief period of time, then releasing. The biological purpose of the velum is to separate the oral cavity from the nasal cavity. This needs to be done during swallowing, unless you want your mild squirting out your nose.

20. Model of the Biological Function of the Velum
Here is a model of the vocal tract and its 3 cavities, including the velum
When the velum is open (lowered), as in breathing—the nasal cavity is connected to the oral cavity. Some speech sounds in English need to have the velum open, and the air leaves the aric/reson system thru the nose during the production of these sounds. Which ones are they—any sound you CAN’T make while blocking your nose. Think /m/, /n/, /ing/.
When the velum is closed (raised), as in swallowing and during the production of most English sounds, the nasal cavity is blocked from the oral cavity.
We’ll talk later on in the semester about speech disorders that interfere with the closure of the velum.

21. Hard and Soft Palates Hard palate Soft palate (velum)
Here’s a cross-sectional view of both the hard and soft palates

22. Important Structures of the Vocal Tract
The tongue
A number of extrinsic and intrinsic musles make up the tongue
Important structures for speech production:
4. The tongue: Most people think that the tongue is one big muscle, but in fact it is comprised of a number of extrinsic and intrinsic muscles.

23. Major Muscles of the Tongue
Responsible for moving the tongue around in the oral cavity
There are 4 major intrinsic muscles of the tongue that are primarily responsible for moving the tongue around in the oral cavity.

24. Life-Span Issues of the Articulatory/Resonating System
Skull
Size
Number of separate plates
Fusing of plates
Lower bones of the face
Tongue and lips
Life-span issues of the aric/reson system:
The skull:
At birth, the skull is of course smaller than the adult skull, and consists of 45 separate plates which are not fused (to allow for growth). By the time a child is about 8, the skull reaches its adult size and all the plates of the skull fuse. The cranium then appears as a solid bony covering.
The lower bones of the face grow at a much slower rate than the skull, and don’t reach their adult proportions until early adulthood.
The tongue and the lips also go thru a maturation process and don’t reach their adult proportions until the teenage years.

25. Speech Production Process
Vibration of the vocal folds
The glottal source
Modification of the glottal source by the vocal tract
Speech Production Process:
We need to consider two broad components of the speech production process, the vibration of the vocal folds (the glottal source) and the modification of the glottal source by movements of the articulators.

26. Phonation
Folds are adducted by contraction of the intrinsic larygeal adductors
Glottis closes
Phonation:
Phonation is initiated by adducting the vocal folds (bring them together). This closes the glottis, or the space between the vocal folds. The folds are brought together by contraction of the intrinsic laryngeal muscles that adduct the folds (lateral cricoarytenoid and interarytenoid muscles).

27. Phonation Subglottic pressure increases
Once the folds are closed, air continues to be expelled from the lungs (exhalation). This causes the air pressure below the level of the glottis to increase. Called subglottic pressure. So this increases.

28. Phonation
Subglottic pressure reaches a critical level and blows the vocal folds apart
Air rushing through the glottis causes negative pressure that helps pull the folds back together
Bernoulli Effect
As the subglottic air pressure increases and reaches a critical level, the focal fold tissue is moved laterally (to the side) and superiorly (upward) and the vocal folds are blown apart.
Air rushes through the glottis. This causes a negative pressure (kind of like a vacuum) between the edges of the folds. This will suck the folds together and helps to abduct (close) the folds. This phenomenon is called the Bernoulli Effect.
Remember that we also have abductor muscles of the folds, so these muscles also help close the glottis. In addition, the natural elasticity of the folds also acts to restore them to their original closed position.
Each time the folds open and close one time, this is one cycle of vocal fold vibration, and sets the air in the vocal tract into vibration and creates sound.

29. Important Characteristics of the Glottal Source
Fundamental Frequency
Rate of vocal fold vibration
Determines the pitch of the voice
Spectrum
CD ROM demos
12.06 and 12.08
Some important characteristics of the sound characteristic of the glottal source:
Fundamental frequency—rate of vocal fold vibration. Determines the pitch of our voice. Men have the lowest fundamental frequencies (usually around 125 Hz). Women’s fundamental frequencies are usually higher (about 250 Hz). Kids are really high, sometimes around 500 Hz.
Fundamental freq is related to the size, thickness, and elasticity of the folds.
Spectrum of the glottal pulse: complex sound. Fundamentals related to rate of vocal fold vibration.

30. Spectrum of the Glottal Source
Modification by the vocal tract: the vocal tract is an acoustic resonator that acts to modify the quality of sound produced by the larynx.
Some frequencies in the spectrum of the glottal spectrum will be reduced in amplitude while other frequencies will be enhanced.
Movements of the tongue, lips, and larynx will change the shape of the vocal tract and cause this modification of the original sound.

31. Articulatory Classification System
Talk about how English speech sounds are classified according to their Place of articulation, manner of articulation and voicing.