phonatory system lecture 8
Post on 06-Jan-2016
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• Bone• Cartilage• Ligament• Membrane• Muscle
• Innervation• Extrinsic muscles• Intrinsic muscles• How the vocal
folds vibrate• Initiating vibration• Pitch• Registers
• Vagus (CN X)• Superior laryngeal nerve:
• Cricothyroid (CT)
• Recurrent laryngeal nerve: • Thyroarytenoid (TA)• Posterior Cricoarytenoid (PCA)
• Lateral Cricoarytenoids (LCA)• Interarytenoids (IA)
Blumenfeld, H., 2002, Neuroanatomy through Clinical Cases, Sinauer, Inc.
• Many extrinsic laryngeal muscles
• Thyrohyoid•Elevates larynx
• Sternothyroid•Depresses larynx
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 112.
• Innervation• Extrinsic muscles• Intrinsic muscles• How the vocal
folds vibrate• Initiating vibration• Pitch• Registers
• Bulk of the vocal folds• Contractions can result
in:• Shortening the vocal folds
• Pulling thyroid and arytenoid cartilages toward each other
• Increasing the tension of the vocal folds
• Isometric (contracting and not changing length)
• Shorten: decreases pitch• Increase tension:
increases pitchHixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 98.
• When it contracts, it helps to lengthen the vocal folds• It elevates the cricoid arch, and depresses the thyroid
lamina (shortens the space between the cricoid and the thyroid)
• This can help to increase pitch
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 97.
• CT active and TA passive = increase pitch• Increase length• Increase stiffness
• TA active and CT passive = decrease pitch• Decrease length• Decrease stiffness
• TA and CT contract simultaneously = increase pitch• Increase stiffness
• Work in opposition• PCA:
• Rocks arytenoids away from midline
• Opens the vocal folds
• LCA:• Rocks arytenoids toward midline
• Closes the vocal folds
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 100.
• PCA: • Rocks arytenoids away from midline
• ABducts the vocal folds
• LCA:• Rocks arytenoids toward midline
• ADducts the vocal folds
Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 107.
• Transverse: • Pulls arytenoids toward each other
• ADducts the vocal folds
• Oblique:• Tips one arytenoid (apex) toward the other (body)
• ADducts the vocal folds Hixon, T.J., et al. (2008). Preclinical Speech Science: Anatomy Physiology Acoustics Perception. Pg. 101.
• Innervation• Extrinsic muscles• Intrinsic muscles• How the vocal
folds vibrate• Initiating vibration• Pitch• Registers
• Many theories of vocal fold vibration• Myo-elastic aerodynamic theory of vocal fold
vibration• Nonuniform tissue movement: Multimass
models
• Van den Berg, 1958• Based on Bernoulli equation:
P + ½ pv2 = constant• P = pressure• p = fluid density• v = velocity• Please use this formula- I believe the
formula in your book is incorrect.• This equation states that as pressure
increases, velocity decreases (assuming density is constant)
Based on Titze, I.R. (2000). Principles of Voice Production.
• Van den Berg, 1958• Based on Bernoulli equation:
P + ½ pv2 = constant• Basics of this theory:
• When the vocal folds are closed, pressure builds in the subglottal region
• When the pressure is high enough, it forces the vocal folds open
• The vocal folds continue to open further as air rushes out• Once they reach a maximum opening, the elasticity in the
vocal folds pulls them together• The cycle repeats
• Other theories in between, but this is the most recent
• Explains self-sustained oscillation: as the vocal folds continue to oscillate (vibrate), they are able to sustain the same velocity and width of excursion
Titze, I.R. (2000). Principles of Voice Production.
• Upper and lower parts of the vocal folds do not move as one
• The lower part of the vocal folds moves first, followed by the upper part
• Convergent: lower further apart than upper
• Divergent: upper further apart than lower
Titze, I.R. (2000). Principles of Voice Production.
• Innervation• Extrinsic muscles• Intrinsic muscles• How the vocal
folds vibrate• Initiating vibration• Pitch• Registers
• Phonation threshold pressure (PTP): smallest subglottal pressure needed to start self-sustained oscillation
• For low frequency phonation, PTP is around 3-4 cm H20
Zemlin, pg 166.
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