Download the phonatory system is the source of voiced sound

PHONATORY SYSTEM
• the phonatory system is the source of voiced sound
• phonation is the generation of voiced sound
• phonation is accomplished with the larynx (voice box), which is attached to the
top of the trachea, and is the outlet of the respiratory pump into the upper
airway
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THE LARYNX
is the structure at the entrance to the trachea that functions as a valve
biologically and as the source of voice for speech
it can close tightly, as when we lift a heavy object, to make the thorax rigid with
compressed air – providing stability to the body during heavy muscular activity
it can accomplish the explosive movements of a cough, expelling mucus and
irritants at great velocity into the airway
it can valve the air stream so as to produce finely controlled vibrations of two
fleshy cushions called the vocal folds
FUNCTIONS OF THE LARYNX BORROWED FOR SPEECH:
• the ability to open in order to produce about half of the consonants, the half
that are voiceless sounds (these sounds are made with busts and hisses of
noise)
• the ability to close (al the level of the vocal folds) just enough to vibrate when
air pressure pushes against it – these vibrations produce voiced sounds, the
tones that characterize vowels and semivowels particularly
• it is our ability of controlling the rate and manner of vibration of the laryngeal
valve, that accounts for our ability to control pitch, loudness, and to some
extent, quality of speech
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THE LARYNGEAL ANATOMY
supraglottal cavity or supraglottal space or laryngeal aditus
false or ventricular folds
ventricle / ventricular cavity or ventricular space
vocal folds or true vocal folds
subglottal cavity
glottis
LARYNGEAL CARTILAGES
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cricoid
thyroid
arytenoid
– vocal process
– muscular process
– apex
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epiglottis
– important during swallowing
corniculate and cuniform
– no known function during speech production
LARYNGEAL MEMBRANES
Inner Laryngeal Membranes
• quadrangular membrane
– covers the supraglottic space
– its lowest edge “makes” the false/ventricular fold
• conus elasticus
– covers the subglottic space
– its uppermost edge “makes” the vocal ligament
VOCAL FOLDS
located bellow the false/ventricular folds and bellow the ventricular
space/cavity
attach anteriorly to the thyroid cartilage
attach posteriorly to the vocal process of the arytenoid cartilage
the space between the edges of the right and left vocal folds is known as
glottis or glottic space
histologically is “made-up” by 5 layers of tissue
– epithelium (most superficial)
– superficial layer of the lamina propria (gelatinous)
– intermediate layer of the lamina propria (elastic fibers like rubber bands)
– deep layer of the lamina propria (collagenous fiber like threads)
– vocalis muscle
vocal ligament
– upper most medial edge of the conus elastic membrane
– histologically
• intermediate layer of the lamina propria (elastic fibers like rubber bands)
• deep layer of the lamina propria (collagenous fiber like threads)
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LARYNGEAL MUSCLES
intrinsic (move the arytenoids and control tension/length/mass of vocal folds )
extrinsic (move the entire larynx)
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INTRINSIC LARYNGEAL MUSCLES
thyroarytenoid (tenses and relaxes)
– external/lateral thyroarytenoid - thyromuscularis - shorten the folds/act as
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relaxor
– internal/medial thyroarytenoid - thyrovocalis/vocalis - tenses the folds
during isometric contraction
• isotonic
• isometric
cricothyroid (tenses)
posterior cricoarytenoid (the only abductor muscle - move folds away from
midline)
lateral cricoarytenoid (one of the adductor muscles - move the folds towards
the midline)
interarytenoids (the other adductor muscles - move folds towards the midline)
– oblique arytenoids (or oblique interarytenoid)
– transverse arytenoids (or transverse interarytenoid)
aryepiglottic (epiglottis down) and thyroepiglottic (epiglottis up)
– confusion regarding these muscles: not all people have this muscle fibers
and still their epiglottis is moved up and down
ADDUCTION OF VOCAL FOLDS
movement of the folds towards the midline
it is accomplished by gliding the arytenoids on top of the cricoid
– lateral cricoarytenoid
– oblique inter arytenoid
– transverse interarytenoid
action of adductory muscles results in medial compression of the folds
(squeeze the folds tightly at midline)
GLOTTAL VIBRATION CAN ONLY BE ACCOMPLISHED WHEN THE
VOCAL FOLDS ARE ADDUCTED / approximated at the midline
ABDUCTION OF FOLDS
movement of the folds away from the midline
it is accomplished by rocking the arytenoids on top of the cricoid
– posterior cricoarytenoid
action of abductor muscle results in required for production of voiceless
sounds
GLOTTAL VIBRATION CAN NOT BE ACCOMPLISHED WHEN THE VOCAL
FOLDS ARE ABDUCTED
EXTRINSIC LARYNGEAL MUSCLES
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suprahyoid
infrahyoid
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SUPRAHYOID MUSCLES
one attachment at hyoid bone and the other attachment above it
pulls the larynx up or the tongue forward or backward
– mylohyoid
– geniohyoid
– digastric
– stylohyoid
INFRAHYOID MUSCLES
one attachment at hyoid bone and the other attachment below it
pulls the hyoid bone down
– sternohyoid
– omohyoid
pulls the larynx upward
– thyrohyoid
pulls the larynx downward
– sternohyoid