Function of the Larynx and the Thyroarytenoid

Layers of the Vocal Folds

1. Layer of epithelium covering the mucous membrane -extremely thin, but tough layer of tissue -basement membrane beneath it 2. Lamina Propria -Superficial layer-made of mostly elastic fibers giving it a high degree of pliability -Intermediate layer- elastic fibers, but more dense and less flexible than superficial layer -Deep layer- mostly collagen fibers, is less flexible than intermediate layer 3. Thyrovocalis-Thyroarytenoid muscles -Thicker and denser than outer layers -The mass of VF

Non-speech function of the Larynx

Abdominal fixation -impounds air in thorax to stabilize the torso -or captures air in the thorax to provide structure for muscles to push or pull Lifting=grunting -vocal folds permit a person to hold their breath plays role in swimming

Valves within the larynx

False( Ventricular) Vocal Folds True Vocal Folds

Vocal Fold Terminology Orientation to Glottis

Glottis -space between the vocal folds -most important laryngeal space for speech Anterior aspect of glottis= anterior commissure Posterior aspect of glottis=posterior commissure Subglottal -area below vocal folds

False(Ventricular) Vocal Folds

Lie inferior to aryepiglottic folds Superior and parallel to true vocal folds Limited movement; can't tense Laryngeal ventricle -Extends length of VF

Thyromuscularis Muscle( lateral thyroarytenoid)

Origin: Inner surface of thyroid near notch Course: Back Insert: muscular process and base or arytenoid Function: Relaxes VFs

Thyrovocalis Muscle(Vocalis)

Origin: inner surface thyroid cartilage near notch Course: back Inserts: Lateral surface of vocal process of arytenoid Innervation: X vagus nerve, recurrent laryngeal nerve Function: when opposed by cricothyroid, tense VF Antagonist of Cricothyroid(CT)

What function does the larynx play in speech?

Phonation -also known as voicing -product of vibrating vocal folds -occurs within the larynx

What role does phonation play in speech?

Phonemic level(segmental level) -Voiceless sounds- produced without use of vocal folds -Voiced sounds- produced by action of vocal folds Supra-segmental level -Pitch and loudness change in words convey stress -Pitch change in sentences conveys linguistic meaning(question vs. command) and emotion

What is the primary function of the Larynx?

Protect the airway Protective function is the most important role of the larynx -Clamps airway in response to possible intrusion by -foreign objects(food or liquid) Vocal folds-wired to close immediately -Prevents entrance of foreign objects into the lungs Coughing- forceful evacuation of respiratory passageway Throat clearing-clears respiratory tract of mucus

Glottis

Space between the true vocal folds Open during quite breathing(but not to greatest extend)

Thyroarytenoid Muscle

Two Parts -Thyrovocalis Muscle-Tenses -Thyromuscularis Muscle-Relaxes

General Aspects of VF Vibration

aDDuction=together aBDuction=apart Requires subglottal pressure Muscles for adduction and abduction but not vibration the muscles do not vibrate they move the VF into position Occurs with a frequency of approximately 110 Hz in men and 220 Hz in women Hz=cycles per second

Valve of larynx that provides lubrication

laryngeal ventricle- between the false folds and the true folds