Laryngology physiology of speech and voice Flashcards
True/False. A unilateral cortical stroke will always
result in vocal-fold paralysis.
False. True vocal-fold motion is controlled by the brainstem
via both pyramidal and extrapyramidal neural systems. The
cell bodies of motor nerves reside within the nucleus
ambiguus, whereas sensory nerves reside within the nodose
ganglion. Therefore, cortical strokes rarely result in cord
paralysis.
Vascular insult to what structure(s) may result in loss of pain/temperature sensation in the ipsi-
lateral face and contralateral body, ipsilateral facial pain, ataxia, nystagmus, vertigo, nausea, vomiting, dysphonia, dysphagia, and Horner syndrome?
Vertebral artery or posterior inferior cerebellar artery
Wallenburg syndrome
The superior laryngeal nerve branches off the
vagus nerve just caudal to what important neural
structure?
The nodose ganglion
What are the three levels of laryngeal airway
protection?
Epiglottis
False vocal folds
True vocal folds
On physical examination, you note that a patient
demonstrates a protective cough reflex with
palpation of the tip of epiglottis but has no
response to palpation of the lower laryngeal
surface of the epiglottis or arytenoid mucosa.
Which nerve is most likely injured?
Superior laryngeal nerve
The tip of the epiglottis receives sensory innervation from
the glossopharyngeal nerve (IX), and the lower epiglottis
and arytenoid regions are innervated by the internal branch
of the superior laryngeal nerve.
The laryngeal closure reflex can be driven by several different stimuli. Name four.
● Thermal
● Mechanical
● Chemical
● Taste
During intubation, what hemodynamic response
may occur due to laryngeal irritation?
Bradycardia and hypotension; cardiovascular collapse
Circulatory laryngeal reflex (superior laryngeal nerve [SLN],
perhaps RLN as well) →central neurons →vagus →heart)
What are the three types of laryngeal respiratory
receptors?
● Negative pressure receptors: Maintain airway patency
during inspiration
● Airflow receptors: Cold receptors, which are stimulated by
air movement
● Respiratory drive receptors: Provide laryngeal propriocep-
tion
What are three fundamental components of
speech?
● Phonation: Vocal-fold vibration resulting in sound generation
● Resonance: Modulation of laryngeal phonation by induction of vibration within the vocal tract
● Articulation: Manipulation of the sound into words
What is required for voice production?
● Power: Adequate breath support (lungs)
● Source of vibration: Larynx
● Resonator: Supraglottic vocal tract and pharynx
Note: Normal phonation requires a good vibratory medium;
normal vocal-fold shape; and the ability to modify the
tension, length, and shape of the true vocal folds.
How does injury to the superior laryngeal nerve impact voice production?
Loss of upper pitch register due to the loss of the motor
innervation to the cricothyroid muscle via the external
branch of the SLN, resulting in the inability to increase vocal tension
The intensity or loudness of sound production is
directly related to air pressure in what location?
Subglottis
Describe the cover-body theory of voice
production.
The cover (SLP) and body (thyroarytenoid muscle) move at
different rates as air moves through the glottis because of
their distinct masses and composition. This variation causes
vibration, which results in a buzzing sound. The supraglottic
vocal tract then modulates this sound to produce voice.
Pitch (or frequency) can be altered by adjusting
the length and tension of the vocal fold. If this is
done by contraction of the thyroarytenoid or
cricothyroid muscle, what nerves are involved?
● Thyroarytenoid: RLN
● Cricothyroid: External branch of the SLN
Given a constant volume of airflow through the
vocal tract, the airflow velocity will increase at the
level of the true vocal folds. Increased velocity
results in decreased pressure and an inward
movement of the vocal folds. What name is given
to this effect?
Bernoulli effect
