Larynx* Flashcards
What is the primary function of the larynx?
To protect the lower respiratory tract preventing inhalation of food/liquid during swallowing or vomitting.
What is the secondary function of the larynx?
To generate noise by vibration of vocal folds (phonation).
Explain the structure of the larynx.
It is part of the respiratory tract and is reinforced by cartilage. The cartilages articulate with each other meaning they can be moved with precision.
What are the key structures of the laryngeal skeleton?
Hyoid bone, thyroid cartilage, cricoid cartilage, arytenoid cartilage and epiglottis.
What is the cricoid cartilage?
It is the only complete ring of cartilage in the respiratory system, it is signet in shape.
Explain the structure of the arytenoids.
The vocal folds attach to the vocal processes of the arytenoids and to the thyroid cartilage.
They form 2 synovial joints with the cricoid lamina - the cricoarytenoids (they can rotate, slide & tilt).
Explain the structure of the laryngeal folds.
The larynx is constricted by the conus elasticus which extends between the cricoid and vocal ligaments.
The vocal folds are bulked out with muscle. Vestibular folds contain mucous glands for lubrication.
What is the positioning of the vocal folds?
They are usually open except during swallowing and speech.
What is the role of the inter arytenoid muscles?
adduct the arytenoid cartilages and close the vocal folds.
What is the role of the posterior cricoarytenoid muscles?
The posterior cricoarytenoid muscles are the ONLY openers of the vocal folds.
What are the thyroarytenoid and later cricoarytenoid muscles used for?
They rotate the arytenoids inwards and close the vocal folds. They are used during swallowing and shouting forcibly (closing the vocal folds).
Explain the process of phonation.
It requires the closure of the vocal folds to raise subglottal pressure beneath the vocal folds, which then causes the vocal folds to open. This cycle is repeated.
What does the vocalis muscle do?
It pulls the arytenoid cartilages forwards towards the thyroid cartilage therefore relaxing the VF’s.
What happens if there is damage to the superior laryngeal nerve?
Loss of sensation to larynx - causes cough reflex to be inoperative.
Loss of motor innervation to cricothyroid muscle - difficulty regulating pitch.
What happens if there is damage to the recurrent laryngeal nerve?
Muscles will become paralyzed. Interarytenoids will become weak so VF’s partially adducted - harsh raspy voice.
