CSD310 Midterm

Glottis: Location and boundaries

• The glottis is the space between the true vocal folds.

• Extends from the anterior commissure to the vocal processes of the arytenoid cartilages.

• It is the opening where air passes during breathing and phonation.

Memory Tip: Glottis = Gap between the vocal folds.

What structures are above the glottis?

The supraglottis includes:

• Epiglottis

• Aryepiglottic folds

• False (vestibular) vocal folds

• Laryngeal vestibule

Function:

• Protects the airway during swallowing.

• Helps direct food away from the trachea.

What structures are below the glottis?

The subglottis:

• Begins immediately below the true vocal folds.

• Extends to the lower border of the cricoid cartilage.

• Continues into the trachea.

Clinical Note:
Swelling of the subglottis can significantly reduce airflow.

Thyroid cartilage

• Largest cartilage of the larynx.

• Shield-shaped.

• Forms the laryngeal prominence (Adam's apple).

• Protects the vocal folds.

• Connected to the hyoid bone by the thyrohyoid membrane.

Memory Tip:
"Thyroid = Shield."

Cricoid cartilage

• Only complete ring of cartilage in the airway.

• Located inferior to the thyroid cartilage.

• Forms the base of the larynx.

• Supports the arytenoid cartilages.

Memory Tip:
Cricoid = Complete ring.

Arytenoid cartilages

• Paired pyramid-shaped cartilages.

• Sit on top of the cricoid cartilage.

• Vocal folds attach to the vocal processes.

• Rotate and glide to open and close the vocal folds.

Function:
Essential for phonation and breathing.

Epiglottis

• Leaf-shaped cartilage.

• Made of elastic cartilage.

• Covers the laryngeal inlet during swallowing.

• Helps prevent food and liquid from entering the airway.

• Returns upright during breathing.

Corniculate cartilages

• Small horn-shaped cartilages.

• Sit on top of the arytenoids.

• Help support the aryepiglottic folds.

Cuneiform cartilages

• Small rod-shaped cartilages.

• Embedded within the aryepiglottic folds.

• Help maintain the shape of the laryngeal opening.

Joint responsible for increasing pitch

Cricothyroid Joint

Function:

• Tilts the thyroid cartilage forward.

• Lengthens the vocal folds.

• Increases vocal fold tension.

• Produces a higher pitch.

• Clinical Tip:
  The cricothyroid muscle acts on this joint.

  Memory:
  CT = Creates Tension

Posterior Cricoarytenoid (PCA)

Function:

• Only intrinsic muscle that abducts the vocal folds.

• Opens the glottis during breathing.

• Rotates arytenoid cartilages laterally.

Clinical Significance:
Paralysis may cause airway obstruction.

Memory:
PCA = Pulls Cords Apart

Lateral Cricoarytenoid (LCA)

Function:

• Primary adductor.

• Rotates arytenoids medially.

• Closes the membranous vocal folds.

Memory:
LCA = Locks Cords Together

Interarytenoid Muscles

Includes:

• Transverse arytenoid

• Oblique arytenoid

Function:

• Pull arytenoids together.

• Close the posterior glottis.

• Assist with phonation and airway protection.

Cricothyroid Muscle

Function:

• Lengthens vocal folds.

• Increases longitudinal tension.

• Raises pitch.

Innervation:
External branch of the Superior Laryngeal Nerve.

Vocalis Muscle

Function:

• Fine-tunes vocal fold tension.

• Makes subtle pitch adjustments.

• Lies within the vocal fold.

Is whispering voiced?

No.

Whispering is:

• Unvoiced

• Produced by turbulent airflow

• Vocal folds do not vibrate

Whisper glottal configuration

• Membranous vocal folds are adducted.

• Posterior cartilaginous glottis remains open.

• Forms the whisper triangle.

• Air passes through the opening and creates turbulent noise.

Pulse Register (Vocal Fry)

• Lowest vocal register.

• Slack, short vocal folds.

• Low-frequency vibration.

• Slow vibration rate.

Falsetto Register

• Highest register.

• Vocal folds are elongated and tense.

• Only thin edges vibrate.

• Produces high-frequency sounds.

Tidal Volume (TV)

Amount of air inhaled or exhaled during one normal, quiet breath.

Inspiratory Reserve Volume (IRV)

Maximum amount of additional air inhaled after a normal inspiration.

Expiratory Reserve Volume (ERV)

Maximum amount of additional air exhaled after a normal expiration.

Residual Volume (RV)

Amount of air remaining in the lungs after maximum expiration.

Cannot be voluntarily exhaled.

Inspiratory Capacity (IC)

Formula:

TV + IRV

Maximum amount of air inspired after a normal expiration.

Functional Residual Capacity (FRC)

Formula:

ERV + RV

Amount of air remaining after a normal expiration.

Vital Capacity (VC)

Formula:

TV + IRV + ERV

Maximum amount of air exhaled after maximum inspiration.

Total Lung Capacity (TLC)

Formula:

TV + IRV + ERV + RV

Maximum amount of air the lungs can contain.

Typical quiet breathing rate for a healthy adult

• 12–20 breaths per minute

• Also called the resting respiratory rate.

• Speech typically occurs during controlled exhalation.

Typical respiratory rate for a newborn

• Approximately 30–60 breaths per minute

• Much faster than adults because newborns have smaller lungs and a higher metabolic demand.

Effect of very low subglottal pressure on speech intensity

• Produces reduced loudness.

• Less air pressure beneath the vocal folds creates softer speech.

• May make speech difficult to hear.

Effect of low subglottal pressure on sustained phonation

• Shorter maximum phonation time.

• Voice may sound weak or breathy.

• Speaker may need frequent breaths while talking.

Which cranial nerve controls tongue movement?

Hypoglossal Nerve (CN XII)

Function:

• Controls intrinsic and extrinsic tongue muscles.

• Essential for articulation and swallowing.

Memory:
Tongue = XII

Which cranial nerve controls facial expression and the lips?

Facial Nerve (CN VII)

Function:

• Controls muscles of facial expression.

• Innervates orbicularis oris and buccinator.

• Important for lip closure and speech.

Memory:
Smile = VII

Which cranial nerve innervates the intrinsic laryngeal muscles?

Vagus Nerve (CN X)

Function:

• Provides motor control to the larynx.

• Controls phonation and airway protection.

Which branch of CN X innervates the cricothyroid muscle?

External branch of the Superior Laryngeal Nerve

Function:

• Innervates the cricothyroid.

• Increases vocal fold tension.

• Raises pitch.

Which branch of CN X innervates most intrinsic laryngeal muscles?

Recurrent Laryngeal Nerve

Function:

• Innervates every intrinsic muscle except the cricothyroid.

• Controls vocal fold opening and closing.

Memory:
RLN = Rest of the Larynx

Plane that divides the body into front and back

Coronal (Frontal) Plane

• Anterior vs. posterior

Sagittal Plane

Divides the body into:

• Left

• Right

Transverse Plane

Divides the body into:

• Superior

• Inferior

Bone that forms the cheekbones

Zygomatic Bone

• Gives shape to the cheeks.

• Forms part of the orbit.

Bone that forms the posterior skull and cranial base

Occipital Bone

• Contains the foramen magnum.

• Protects the posterior brain.

Posterior quarter of the hard palate

Formed by the:

Palatine Bones

The anterior three-fourths are formed by the maxillae.

Immobile articulators

Structures that do not move during speech:

• Hard palate

• Alveolar ridge

• Upper teeth

Mobile articulators

Structures that move during speech:

• Tongue

• Lips

• Velum (soft palate)

• Mandible (jaw)

Orbicularis Oris

Function:

• Puckers the lips.

• Closes the lips.

• Important for sounds like:

  • /p/

  • /b/

  • /m/

Buccinator

unction:

• Compresses the cheeks.

• Keeps food between the teeth during chewing.

• Helps maintain airflow during speech.

Canine Teeth

Function:

• Tearing food.

• Have one pointed cusp.

Premolars

Function:

• Crush food.

• Transitional teeth between canines and molars.

Molars

Function:

• Grind food.

• Broad chewing surface.

Memory:
Molars = Mash

What indicates greater intensity on a waveform?

Greater amplitude

Higher amplitude = louder sound.

Why doesn't duration determine intensity?

A sound can be:

• Long but quiet.

• Short but loud.

Intensity depends on amplitude, not duration.

Five layers of the vocal folds (superficial → deep)

Back

1. Epithelium

2. Superficial Lamina Propria

3. Intermediate Lamina Propria

4. Deep Lamina Propria

5. Vocalis Muscle

Memory:
Every Smart Instructor Drinks Vodka
(Epithelium, Superficial, Intermediate, Deep, Vocalis)

Which layers make up the cover?

The cover consists of:

• Epithelium

• Superficial lamina propria

These layers are flexible and vibrate during phonation.

What is the body of the vocal fold?

The body consists primarily of the:

Vocalis muscle

Provides stability and support during vibration.

What is the transition?

The transition consists of:

• Intermediate lamina propria

• Deep lamina propria

Also called the vocal ligament.

Region at the vocal folds

Glottis

Space between the true vocal folds.

What is the onset of phonation?

• Onset is the beginning of vocal fold vibration.

• Occurs when the vocal folds adduct and subglottal air pressure is sufficient to initiate vibration.

• Marks the start of voiced sound production.

Memory Tip: Onset = "On" (voice begins).

What is the offset of phonation?

• Offset is the end of vocal fold vibration.

• Occurs when the vocal folds abduct and voicing stops.

• Marks the transition back to breathing.

Memory Tip: Offset = "Off" (voice ends).

Rank the primary functions of the larynx in order of survival importance.

1. Airway protection

2. Breathing (air passage)

3. Voice production (phonation)

Clinical Note:
The larynx evolved first to protect the airway. Speech is its least essential function for survival.

Thoracic vertebrae are ______ relative to the lumbar vertebrae.

Thoracic vertebrae are above the lumbar vertebrae.

Which vessels travel through the transverse foramina of the cervical vertebrae?

Vertebral arteriesFunction:

• Supply blood to the brainstem and posterior brain.

Memory Tip:
V = Vertebral arteries travel through Vertebrae.

Trace the airflow pathway from the nose to the alveoli.

1. Nose (or mouth)

2. Nasal cavity

3. Pharynx

4. Larynx

5. Trachea

6. Primary (main) bronchi

7. Secondary (lobar) bronchi

8. Tertiary (segmental) bronchi

9. Bronchioles

10. Terminal bronchioles

11. Respiratory bronchioles

12. Alveolar ducts

13. Alveolar sacs

14. Alveoli (site of gas exchange)

Memory Tip: Air always moves from larger airways to smaller airways until it reaches the alveoli.

What happens during quiet inspiration?

• Diaphragm contracts and moves downward.

• External intercostal muscles contract.

• Thoracic cavity expands.

• Lung volume increases.

• Intrapulmonary pressure decreases.

• Air flows into the lungs.

What happens when the diaphragm relaxes?

• Diaphragm rises back to its resting position.

• Thoracic cavity becomes smaller.

• Lung volume decreases.

• Intrapulmonary pressure increases.

• Air flows out of the lungs.

What is Boyle's Law?

• Pressure and volume have an inverse relationship.

• As volume increases, pressure decreases.

• As volume decreases, pressure increases.

Speech Connection:
Boyle's Law explains how breathing creates the airflow needed for speech.

Memory Tip:

• Big lungs = Small pressure

• Small lungs = Big pressure

How does Boyle's Law explain inspiration?

During inspiration:

• Thoracic volume increases.

• Lung pressure decreases below atmospheric pressure.

• Air flows into the lungs.

How does Boyle's Law explain expiration?

During expiration:

• Thoracic volume decreases.

• Lung pressure increases above atmospheric pressure.

• Air flows out of the lungs

What is the Bernoulli Effect?

• As the velocity of airflow increases, air pressure decreases.

• Helps draw the vocal folds back together during phonation after they have been pushed apart by subglottal pressure.

• Works together with tissue elasticity to sustain vocal fold vibration.

Memory Tip:
Fast air = Low pressure

What role does the Bernoulli Effect play during a glottal cycle?

During phonation:

1. Subglottal pressure pushes the vocal folds apart.

2. Air speeds through the narrow glottis.

3. Pressure between the folds decreases (Bernoulli Effect).

4. The vocal folds are drawn back together.

5. The cycle repeats rapidly to produce voice.

What is the position of the velum during normal speech?

• Closes the velopharyngeal port.

• Prevents air from escaping through the nose.

• Produces oral speech sounds.

What is the position of the velum during nasal sounds?

Lowered

• Opens the velopharyngeal port.

• Allows air to pass through the nasal cavity.

What are the three nasal consonants in English?

• /m/

• /n/

• /ŋ/ ("ng" as in sing)

What structure is the site of gas exchange?

Alveoli

• Oxygen diffuses into the blood.

• Carbon dioxide diffuses into the lungs

What creates the power source for speech?

The respiratory system

• Provides the airflow needed for phonation.

• Controlled exhalation powers speech production.

What two forces are responsible for vocal fold vibration?

1. Subglottal air pressure

2. Bernoulli Effect (along with tissue elasticity)

Together they maintain the vibratory cycle during phonation.

What are the three regions of the larynx?

• Supraglottis – above the true vocal folds

• Glottis – true vocal folds and the space between them

• Subglottis – below the true vocal folds to the trachea

Which laryngeal cartilage is NOT paired?

Unpaired cartilages:

• Thyroid

• Cricoid

• Epiglottis

Paired cartilages:

• Arytenoids

• Corniculates

• Cuneiforms

Memory:
TCE = Thyroid, Cricoid, Epiglottis (unpaired)

Which intrinsic laryngeal muscle is the only abductor?

Posterior Cricoarytenoid (PCA)

Function:

• Opens the vocal folds.

• Essential for breathing.

Memory:
PCA = Pulls Cords Apart

Which intrinsic muscles adduct the vocal folds?

Back

• Lateral cricoarytenoid

• Transverse arytenoid

• Oblique arytenoid

Function:

• Close the vocal folds for phonation.

Which muscle raises vocal pitch?

Cricothyroid

Function:

• Lengthens the vocal folds.

• Increases tension.

• Produces a higher pitch.

Cover–Body Theory

Cover

• Epithelium

• Superficial lamina propria

Transition

• Intermediate lamina propria

• Deep lamina propria (vocal ligament)

Body

• Vocalis muscle

Clinical Note:
The cover is the primary vibrating portion during phonation.

Five vocal fold layers (superficial → deep)

1. Epithelium

2. Superficial lamina propria

3. Intermediate lamina propria

4. Deep lamina propria

5. Vocalis muscle

What muscle is primarily responsible for quiet inspiration?

Diaphragm

• Contracts and flattens.

• Increases thoracic volume.

• Draws air into the lungs.

What is the power source for speech?

The respiratory system.

Speech depends on controlled expiratory airflow generated by the lungs.

What determines vocal loudness?

Subglottal pressure

More pressure beneath the vocal folds = louder voice.

What determines vocal pitch?

Pitch depends on:

• Vocal fold length

• Vocal fold tension

• Rate of vibration (frequency)

CN VII

Facial Nerve

Functions:

• Facial expression

• Lip movement

• Orbicularis oris

• Buccinator

CN X

Vagus Nerve

Functions:

• Controls the larynx.

• Responsible for phonation.

• Includes the Superior Laryngeal and Recurrent Laryngeal nerves.

CN XII

Hypoglossal Nerve

Function:

• Controls tongue movement.

• Essential for articulation.

Correct sequence of speech production

1. Respiration

2. Phonation

3. Resonance

4. Articulation

Memory:
Air → Voice → Resonance → Speech

What structure controls oral vs. nasal resonance?

Velum (Soft Palate)

Raised:

• Oral sounds

Lowered:

• Nasal sounds

English nasal consonants

• /m/

• /n/

• /ŋ/

Boyle's Law

Pressure and volume are inversely related.

↑ Volume = ↓ Pressure

↓

Volume = ↑ Pressure

Bernoulli Effect

As airflow velocity increases,
pressure decreases.

Helps pull the vocal folds back together during vibration.

Site of gas exchange

Alveoli

Oxygen enters the bloodstream.

Carbon dioxide leaves the bloodstream.

Airflow pathway (short version)

Nose

↓

Pharynx

↓

Larynx

↓

Trachea

↓Bronchi

↓

Bronchioles

↓

Alveoli

Major mobile articulator

• Tongue

• Lips

• Velum

• Mandible

Major immobile articulators

• Hard palate

• Alveolar ridge

• Upper teeth