Anatomy Test #3

Primary purpose of the larynx

 To close off the airway

How does protection of the airway work

 the airway is sealed off and can be cleared with a cough

How does thoracic fixation work

the thorax is stabilized and enables pressure buildup

What the larynx does for speech production

functions as a voice box for phonation

What is phonation

voicing/ vibration of the vocal folds

Why can we consider the larynx a 2-way valve?

Because it lets food in and air out

Cricoid cartilage

specialized tracheal ring, is the only one not open in the back, most inferior larnygeal hyaline cartilage

Thyroid cartilage

the largest laryngeal cartilage, anterior point of attachment inside for vocal folds, hyaline cartilage

Arytenoid cartilage

 ride on the posterior surface of the cricoid cartilage, posterior point of attachment for vocal folds, mostly hyaline

Cricoarytenoid movement

rocking, gliding and rotation

Cricothyroid movement

rotation and gliding

Intrinsic membranes

made up of quadrangular membrane and conus elasticus which are the two major sections that cover the inside of the larynx

Extrinsic membranes

 connect the larynx with surrounding structures

Both true and false vocal folds are located

By connecting the thyroid cartilage to the arytenoids

Purpose of true vocal folds

produce vocal sound, aid with breathing and swallowing

Purpose of false vocal folds

 Close for swallowing and thoracic fixation

Differences true vs. false vocal folds

False vocal folds are superior to true vocal folds, true vocal folds have five layers

Similarities true vs. false vocal folds

both connect thyroid to arytenoids 

• Which layers are most compliant? Which layers are least compliant? of vocal folds

Squamous epithelium, superficial, intermediate, deep lamina propria, thyroarytenoid muscle

definition of vocal ligament

Superior margin of conus elasticus

Membranous characteristics

jello-like, bundle of soft rubber bands

Cartilaginous characteristics

bundle of cotton thread, bundle of stiff rubber bands

Glottis

space between the true vocal folds

Subglottis

the lowest part of the larynx

Ventricle

a fluid filled cavity

Vestibule

a passage between inner and outer structures

Anterior commissure

anterior connection point of the true vocal folds

Location of intrinsic laryngeal muscles

have both origin and insertion on laryngeal cartilages

Function, innervation of intrinsic laryngeal muscles

open, close, tense, and relax the vocal folds- fine adjustments control phonation

how phonation works

When the vocal folds are loosely adducted, a passing air stream with enough pressure sets the vocal folds into vibration

Cover vs. transition vs. body and compliance

highly compliant cover vibrates differently than stiff body

Relationship to the mucosal wave

helps explain complexity of vocal folds vibration (mucosal wave)

Myoelastic theory of phonation

muscles adduct and control tension to prepare for phonation at desired pitch

Aerodynamic theory of phonation

vocal folds activated by airstream from lungs and perpetuated by oscillations in air pressure and air flow

position of vocal folds during phonation

Vocal folds are loosely adducted during phonation

What are the changes in velocity and pressure?

Velocity increases as pressure decreaces

What effect does it have on a compliant, narrow constriction?

That if the walls are pliable they will be pushed together

relationship to vocal folds as self-sustaining oscillator (Basically, how does the combination of the myoelastic aerodynamic theory, the cover body theory, and the Bernoulli principle work together to help explain how the vocal folds can oscillate/vibrate at hundreds or thousands of cycles per second without muscular effort [i.e., self-sustaining])

Medial pressure building then Bernoulli principle is in effect, for four cycles, as vocal folds vibrate in a self-sustaining manner.

Infrahyoid

 muscles connect the hyoid to a structure below it

Suprahyoid

 muscles connect the hyoid to a structure above it

Laryngeal depressors

 lower the hyoid and larynx

Lanryngeal elevators

 elevate the hyoid and larynx

role of intrinsic laryngeal muscles during phonation

responsible for sound production and the movements of the laryngeal cartilages and folds themselves

why the vocal folds are blown apart

to allow a steady airstream to flow

why the vocal folds return to midline 

For closure, to prevent things from getting in