Module 4 Quiz

SHS 300

biological functions of larynx

protect trachea and lungs from foreign substances
airway protection during swallowing

non biological function of larynx

voice production

6 laryngeal cartilages

1. Thyroid

2. Cricoid

3. Arytenoid

4. Epiglottis

5. Corniculate

6. Cuneiform

Thyroid cartilage

-Adam's apple
-largest cartilage
-shield like housing of larynx
-hyaline cartilage

thyroid c. function

Protects vocal folds

cricoid cartilage

-lowest part of laryngeal skeleton
-above trachea
-ring shaped structures
-hyaline cartilage

cricoid c. function

Foundation and support for other cartilages
holds everything up

arytenoid cartilage

-PAIRED
-Pyramidal shape with processes

arytenoid c. function

Vocal fold movement

epiglottis cartilage

-leaf like cartilage
-elastic

epiglottis c. function

Airway protection during swallowing

corniculate cartilage

-PAIRED
-sits on apex of arytenoid

corniculate c. function

Supports epiglottis

cuneiform cartilage

-PAIRED
-elastic

cuneiform c. function

Helps maintain opening to larynx by stiffening and supporting aryepiglottic folds

hyoid bone

-a U-shaped bone in the neck that supports the tongue
-attachment for extrinsic laryngeal muscles

hyoid bone on larynx structure

cricothyroid joint movement

rotation and sliding

how cricothryoid movement affects VFs

elongates VFs to affect pitch

cricoarytenoid movement

rocking and gliding

how cricoarytenoid movement affects VFs

abducts or adducts VFs

Intrinsic membranes and ligaments

interconnect laryngeal cartilages and help regulate extent and direction of their movements

main intrinsic membranes

conus elasticus and quadrangular membrane

conus elasticus

-intrinsic

• lower portion of larynx
  -connects cricoid, arytenoid, and thyroid c.
  -supports VFs for sound production

3 parts of conus elasticus

medial cricothyroid ligament, lateral cricothyroid ligament, vocal ligaments

quadrangular membrane

-intrinsic
-upper portion of larynx
-connects epiglottis, arytenoid, corniculate, and thyroid c.
-frames and supports upper larynx and false VFs

5 layers of vocal folds

squamous epithelium, superficial layer of lamina propria, intermediate layer of lamina propria, deep layer of lamina propria, vocalis muscle

2 portions of vocal folds

Membranous portion
-Location: Anterior 2/3 of the vocal fold

• Function: primary sound generator
  Cartilaginous portion
  -Location: Posterior 1/3, near the arytenoid cartilages
  -Function: Provides structural support and connects to the arytenoids

less involved in vibration

extrinsic muscles of larynx

thyrohyoid, sternohyoid, digastric, omohyoid, mylohyoid

extrinsic muscles function

support and stabilize the neck, change larynx position

intrinsic muscles of larynx (5)

Thyroarytenoid, posterior and lateral cricoarytenoid, cricothyroid, anytenoid

why are these muscles called intrinsic

both ends of each muscle have attachments within the larynx

vocal folds

thyromuscularis, thyrovocalis, vocal ligament

thyroarytenoid (TA)

-intrinsic muscle
-regulates internal longitudinal tension
-forms bulk of VFs
-CN X Vagus
-RLN

posterior cricoarytenoid (PCA)

-intrinsic
-Decrease distance between thyroid & arytenoid, relaxing VFs
-decreasing pitch
CN X Vagus
-RLN

lateral cricoarytenoid (LCA)

-intrinsic
-Rocks arytenoids downward and inward → adducts VFs and regulates the medial compression

• CN X Vagus
  -RLN

arytenoid IA

-intrinsic
-Abduct VFs, specifically approximate posterior glottis (cartilaginous portion)
-CN X Vagus
-RLN

cricothyroid CT

-intrinsic
-increases VFs length and tension
-increase pitch
CN X Vagus
SLN

extrinsic muscles (9)

sternothyroid, thyrohyoid, sternohyoid, omohyoid, digastric bellies, stylohyoid, mylohyoid, geniohyoid

sternothyroid

-extrinsic
-depresses larynx

• CN XII hypoglossal

thyrohyoid

-extrinsic
-depresses hyoid and elevates larynx
-CN XII hypoglossal

sternohyoid

-extrinsic
-depresses hyoid bone
-CN XII

omohyoid

-extrinsic
-depresses hyoid bone
-CN XII

anterior belly of digastric

-extrinsic
-move hyoid upward
-depresses mandible
CN V trigeminal

posterior belly of digastric

-extrinsic
-move hyoid upward
-CN VII facial

stylohyoid

-extrinsic
-elevates and retracts hyoid bone
-CN VII facial

mylohyoid

-extrinsic
-forms much of muscular floor of mouth
-CN V trigeminal

geniohyoid

-extrinsic
-elevates hyoid bone
-CN XII hypoglossal

CN that transmits sensory info from laryngeal mucosa

CN X vagus

Myoelastic-Aerodynamic Theory of Voice Production

Vocal fold vibration is a result of the interaction of muscular, elastic recoil, and aerodynamic forces

steps in opening phase of vibratory cycle (Myoelastic-Aerodynamic Theory of Voice Production)

1. Lateral cricoarytenoid (LCA) contracts → adducts (closes) vocal folds
2. Subglottal pressure builds
3. Opening force develops: force exceeds resistance offered by closing VFs
   separation of VFs
4. Lateral excursion of VFs
5. Complete abduction (separation): flow of air dissipates

steps in closing phase of vibratory cycle (Myoelastic-Aerodynamic Theory of Voice Production)

1. Elastic recoil of vocal fold tissue
   returns VFs to equilibrium
2. Aerodynamic Forces and Biochemical Properties
   2a.Inertia: keeps VFs moving closer together
   2b. Pressure differential: shape of glottis changes throughout vibration, affection pressure
   2c. Bernoulli effect: air flowing through a constriction creates suction force perpendicular to movement of air

how do the VFs adduct and abduct for voice production?

Vertical phase & Longitudinal phase

vertical phase def

Vocal folds open bottom-to-top

longitudinal phase def

Wave travels along fold length