Anatomy and physiology of human respiration and phonation

1
Anatomy and physiology of human respiration and
phonation

• Paper 9
• Foundations of Speech Communication
• Sarah Hawkins
• 2 17 October 2008

2
Aims

• To outline principles of muscle behaviour and
  some anatomy and physiology for breath control
  and phonation
• To explore some consequences of these principles
  for aspects of linguistic form

3
Control of muscles in the body

• Muscles are made up of lots of fibres, each one
  of which has its own nerve endings
• A muscle fibre contracts when the neuron (single
  nerve fibre) that innervates it fires and
  relaxes when the neuron stops firing
• Muscle fibres in a single muscle are organised
  into groups (motor units). Each motor unit is
  innervated by a single motor neuron

Nerve fires once ? motor unit twitches once, due
to a chemical reaction. Faster firing ? more
continuous contraction (recruits more motor
units). Too much firing for too long ??
cramp-like state (tetanus)
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Using muscles to move parts of the body

• For most voluntary movement, muscles move one
  part of the body relative to another because each
  muscle is attached to two different solid
  structures, e.g. two bones, across a joint.
• origin of muscle is on one bone
  (which usually stays fixed during contraction)
• insertion is on the other
  (which usually moves)

relaxed
contracted
5
3 types of skilled movement
muscles fix a joint that is next to the joint to
be moved

• Movements of fixation
• opposing groups of muscles(agonistic and
  antagonistic)hold a body part in position
• Controlled movements
• ?? 2 opposing muscle groups work in synergy
• Ballistic movements Plan trajectory to reach a
  target
• the movement consists of a single contraction of
  the agonist muscle group, with the antagonist
  group(s) relaxed. It is impossible to change the
  course of the movement once it is started. The
  antagonist group(s) normally contracts to
  terminate it.

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Summary Principles of skilled movement

• Control high-level coordinates
• identify target
• plan trajectory
• calculate the contribution of each of several
  body parts to the actual trajectory functional
  synergies
• easy example to make /bu/ (boo)lips, jaw,
  and tongue can contribute to different
  degreeshow much each contributes in a given
  instance depends on individual habit, preceding
  and following context (planning for smooth
  transitions etc)

• Later lectures will apply the same types of
  principle to perception
• the big picture matters (the normal goal being to
  understand meaning)
• physically identical sensory detail is used in
  different ways depending on circumstances

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The respiratory pump

• The spongy lungs can be likened to two balloons
  that are inflated and deflated as if by a bicycle
  pump
• The basis for the action of the respiratory pump
  is the way the lungs are linked to the ribcage
  (thorax) and abdomen by two pleurae (membranes).
  A layer of fluid between the pleurae allows them
  to move freely and provides suction to maintain
  the linkage
• The consequence of the linkage is that the lungs
  expand and contract as the ribcage and abdomen
  expand and contract

R abdominal muscles led by rectus abdominus D
diaphragm EI external intercostal muscles II
internal intercostal muscles
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The respiratory pump

• Because volume and pressure are related, altering
  the lung volume changes the air pressure in the
  lungs (Pa, Ps)
• Increasing lung volume (e.g. by pushing the
  ribcage or abdomen outwards) lowers air pressure
• Decreasing lung volume raises air pressure

R abdominal muscles led by rectus abdominus D
diaphragm EI external intercostal muscles II
internal intercostal muscles
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The respiratory pump

• Air flows from regions of higher to lower
  pressure, so air flows into the lungs when
  pressure decreases below atmospheric level, and
  out when pressure increases above atmospheric
  level

R abdominal muscles led by rectus abdominus D
diaphragm EI external intercostal muscles II
internal intercostal muscles
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The respiratory pump

• INspiration / INhalation (breathing IN) normally
  involves muscular effort contracting EXternal
  intercostal muscles (to elevate ribs) and
  diaphragm (which lowers as it contracts,
  expanding volume of thorax).

R abdominal muscles led by rectus abdominus D
diaphragm EI external intercostal muscles II
internal intercostal muscles
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The respiratory pump

• EXpiration / EXhalation (breathing out) can use
  muscular control (mainly contraction of INternal
  intercostal muscles). But this is duringFORCED
  BREATHING
• During quiet breathing, expiration is normally
  passive the elastic recoil force of the lungs
  does most of the work.

R abdominal muscles led by rectus abdominus D
diaphragm EI external intercostal muscles II
internal intercostal muscles
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Breathing for speech

• Speech requires much more muscular control than
  quiet breathing, to sustain the correct pressure
  over the long vocalisations that humans typically
  produce. Without adequate breath control, the air
  goes out too fast.

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Breathing for speech

• Speech requires much more muscular control than
  quiet breathing, to sustain the correct pressure
  over the long vocalisations that humans typically
  produce. Without adequate breath control, the air
  goes out too fast. Ps is normally around 8-10 cm
  H20 during speech.

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Breathing for speech
-60 -30 0 30 60

• Therefore
• At the start of an utterance, the flow of air out
  of the lungs is braked by using the inspiratory
  muscles (external intercostals and/or diaphragm)
  to keep lung volume high
• Once the resting expiratory volume has been
  reached, the expiratory muscles (internal
  intercostals) are used to push air out until the
  end of the utterance.

relaxation pressure
vital capacity
volume for utterance
alveolar pressure (cm H2O)
insp. brake
vital capacity
forced exp.
muscular pressure (cm H2O)
inspiratory expiratory
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Some terminologyLung volumes and capacities
There are 4 volumes and 4 capacities. Each
capacity involves two or more volumes.
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Some terminologyLung volumes and capacities
equilibrium
There are 4 volumes and 4 capacities. Each
capacity involves two or more volumes.
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Life breathing and speech breathing

• Life breathing relatively effortless in healthy
  person
• Neuropathology can affect breathing for speech
  e.g. trying to impose metabolic breathing on
  speech sufferers from anarthria sometimes take a
  breath between each word
• Lung diseases e.g. asthma (inflamation and
  clogging of airways) makes exhalation difficult
• Young childrens lungs are smaller than adults
  their airways are more resistant to airflow. But
  they need to generate approximately the same
  airflows as adults do. Therefore, they need more
  muscular effort (esp. expiratory) to achieve the
  right pressure. Consequences e.g. shorter breath
  groups.

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The larynx

• Biological function
• a valve to keep bad stuff out, and to expel any
  bad stuff that is already in!

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Laryngeal anatomy basic checklist

• 1. 4 main cartilages (cricoid, thyroid, pair of
  arytenoids, epiglottis)
• joined to each other and slung from one bone (the
  hyoid) by membranes
• joined to bones by extrinsic muscles these fix
  it or move it in the neck
• joined to each other by (mainly paired) intrinsic
  muscles which
• move the cartilages relative to one another (4
  main pairs)
• comprise the bulk of the vocal folds (2 pairs)
• 2. The vocal folds are inside (and thus part of)
  the larynx
• bundles of muscle, ligament and mucous membrane
• extend horizontally from the front (thyroid
  notch) to the back (arytenoids)
• space between them is the glottis
• 3. Laryngeal musculature enables vocal fold
  closure and opening (affecting size and shape of
  the glottis) , and all adjustments for phonation
• Innervation part of the vagus, a cranial nerve
  that also controls breathing, heart, digestion
  etc.

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Phonation (voicing) basic checklist

• To phonate, the vocal folds must vibrate
• To vibrate, they must be held close enough
  together to impede the airflow through the
  glottis
• Muscles bring them together hold them there
• The transglottal airflow itself sets them into
  vibration, and maintains the vibration
• myoelastic aerodynamic theory of phonation
• (elastic recoil and Bernoulli forces)

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The larynxanterior (front) view
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The larynxposterior (back) view
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The larynxposterior (back) view
Homework work out what the numbers refer to
http//www.med.umich.edu/lrc/coursepages/M1/anatom
y/html/atlas/images/rsa3p13.gif
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The larynxlateral (side) view
Homework work out what the numbers refer to
http//www.med.umich.edu/lrc/coursepages/M1/anatom
y/html/atlas/images/rsa3p2.gif
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Structure of the larynx

• 3 1 main cartilages
• large thyroid (Adams apple) comprising 2 plates
  and 4 horns. connected upwards to hyoid bone by
  thyrohyoid muscle/ligament)
• smaller, circular cricoid with signet ring
  shape higher at back than front
• 2 small, pyramid-shaped arytenoids sitting on top
  of posterior surface of cricoid
• ( epiglottis up from thryoid angle, rests
  against back of tongue)
• Vocal folds connect vocal process of arytenoids
  to inner front of thyroid cartilage

Front view
View from top
Side view
Rear view
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Inside the larynxmid-sagittal (vertical, middle)
view
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Inside the larynx the vocal folds

• mid-sagittal view

• Vocal folds can be in an open (abducted) or
  closed (adducted) configuration

View from aboveFolds closed (adducted)
View from above Folds open (abducted)
Glottis space between folds
fiberscope_insertion.mov
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Vibration of the vocal foldsresults in phonation
(voicing)

• Myoelastic aerodynamic theory of vocal fold
  vibration (van den Berg, 1950s)
• Muscular activity rotates and rocks the arytenoid
  cartilages so that their vocal processes come
  together in the midline, thus positioning the
  vocal folds close together or in actual contact.
• Air pressure increases below the glottis until
  folds forced apart. (The subglottal pressure
  increase leads to a transglottal pressure drop.)
• Air travels faster through the glottis when it is
  narrow. This causes a local drop in air pressure
  (Bernoulli effect) which causes the folds to be
  sucked towards each other.
• The Bernoulli effect, together with the elastic
  recoil force exerted bythe displaced vocal
  folds, causes complete glottal closure again.
• The process begins again at step 2.

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Vertical views of the vocal folds during one
vibratory cycle
The folds are three-dimensional, and they vibrate
in three dimensions. The pattern of vibration is
like a wave travelling up them. The lower
sections part first, and come together
first. Cover (outer layer) and body (inner
layers) of folds are often distinguished, because
they vibrate fairly independently
After Stevens (1998) Acoustic Phonetics(Baer,
1975)
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Vertical views of the vocal folds during one
vibratory cycle
Two-mass model The pattern of vibration can be
quite well modelled using 2 quasi-independent
masses for each vocal fold. one large, one
small, the two connected by a spring
After Stevens (1998) Acoustic Phonetics(Baer,
1975)
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Vocal foldsduring a vibratory cycle
http//sail.usc.edu/lgoldste/General_Phonetics/La
rynx_film_festival/Demo_320_RLS_1A.mpg
http//cspeech.ucd.ie/fred/teaching/oldcourses/ph
onetics/pics/vfold1.gif
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Controlling phonation Intrinsic laryngeal
muscles

• This lecture does not address external laryngeal
  muscles, nor detailed vocal fold anatomy (read
  e.g. Hardcastle)

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No phonation, or stopping phonation

• Abduction Vocal processes of arytenoids (front
  part) rotated backwards and outwards (posterior
  cricoarytenoid muscle)
• This moves the vocal folds apart and so widens
  the glottis

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Starting and maintaining phonation

• Adduction vocal processes of arytenoids moved
  together (lateral cricoarytenoid, interarytenoid
  muscles)
• This brings the vocal folds together, thus
  closing the glottis

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Pitch control

• Increasing pitch contracting cricothyroid
  muscle pulls front of cricoid up towards
  thyroid, so back of cricoid moves down and back,
  taking arytenoids with it and stretching/tensing
  vfs ? vibrate faster
• vocalis shortens/thickens tenses vocal folds

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Pitch control

• Increasing pitch contracting cricothyroid
  muscle pulls front of cricoid up towards
  thyroid, so back of cricoid moves down and back,
  taking arytenoids with it and stretching/tensing
  vfs ? vibrate faster
• vocalis shortens/thickens and tenses vocal
  folds
• (complex adjustments to length, tension,
  thickness medial compression)

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Voice qualities

• Primarily laryngeal and respiratory
• Classification systems vary from very simple
  e.g. creak - modal -
  breathy, to very complex
• Reasons for variation
• physiological laryngeal physiology is poorly
  understood, partly because there are so many
  degrees of freedom (different combinations of
  controlling factors)
• perceptual and functional multiple factors,
  often with multiple functions

(e.g. Laver) Ladefoged (2001)Vowels and
consonants
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Communicative uses of voice quality

• Cultural some cultures have distinctive voice
  qualities (start noticing if you havent already)
• Indexical part of an individuals characteristic
  speech patterns
• Communicative function
• controlling conversation cf. so, I think,
  and
• conveying affect (emotion)
• Phonetic roles segmental and prosodic
• underpin all the above

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Pathological disordersof vocal fold vibration or
breathing

• e.g.
• neural e.g. paralysis, spastic dysphonia ?
  incomplete closure ? breathy ? quiet usually
  high pitch or harsh if tense. Parkinsons ?
  immobile tremor, quiet, restricted pitch range
  (often high), hoarse
• viral laryngitis ? oedema, dryness ? hoarse, or
  silent
• habitual abuse (shouting, smoking) ? hoarse,
  harsh
• physical damage to the folds (nodules, polyps,
  scars....) incomplete closure irregular
  vibration ? breathy, hoarse, low volume

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Coordinating glottal and oral constrictions

• oral closure oral release
• oral constriction area
• stop VOT
• glottal constriction and vibration aba
  voiced negative
• apa voiceless unasp. zero
• apha voiceless positive aspirated
• ahpa preaspirated
• a?pa glottalised zero
• ab?a breathy
• time
• key
• top row complete oral closure all other
  rows vocal folds adducted but not vibrating
• top row oral articulators open all
  other rows vocal folds abducted and not
  vibrating
• modal phonation vocal folds adducted and
  vibrating
• breathy phonation vocal folds partially
  adducted and vibrating

Air pressures and flows also affect the acoustic
outcome
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Coordinating glottal and oral constrictions

• oral closure oral release
• oral constriction area
• stop VOT
• glottal constriction and vibration aba
  voiced negative
• apa voiceless unasp. zero
• apha voiceless positive aspirated
• ahpa preaspirated
• a?pa glottalised zero
• ab?a breathy
• time
• key
• top row complete oral closure all other
  rows vocal folds adducted but not vibrating
• top row oral articulators open all
  other rows vocal folds abducted and not
  vibrating
• modal phonation vocal folds adducted and
  vibrating
• breathy phonation vocal folds partially
  adducted and vibrating

Air pressures and flows also affect the acoustic
outcome
movie Gujarati Retroflex Unasp vs Aspirated ?

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How does the breath shape the prosody of speech?
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Prosody in speech

• Commonly used to refer to a range of phonetic
  features, such as pitch, loudness, tempo, and
  rhythm.
• To describe the prosody of speech, we need to
  think about levels of organisation larger than
  the phonetic segment, e.g.
• syllable
• foot
• prosodic phrase
• breath group

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Syllable structure
45
Foot structure
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Stress and focus

• Different kinds of prominence borne by syllables
• Lexical stress
• e.g. below ?????? vs. billow ??????
• Sentence stress and focus
• a) (Does Deb love Bob?) No, BEV loves Bob
• b) (Does Bev love Rob?) No, Bev loves BOB

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What is the respiratory contribution to speech
prosody?

• A separate muscular contraction for every
  syllable?
• Classic work by Stetson (1951) proposed that
• The syllable is constituted by a ballistic
  movement of the intercostal muscles.
• This movement is terminated either by a consonant
  constriction (which checks airflow) or by
  contracting the inspiratory muscles
• Longer-term prosodic units (foot, breath group)
  are defined by contractions of the abdominal
  muscles.

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What is the respiratory contribution to speech
prosody?

• Pressure, flow and movement data seemed to
  support Stetsons view.
• But work in the 1950s using electromyography and
  other techniques (e.g. Draper, Ladefoged and
  Whitteridge 1959, Ladefoged 1967) discredited it.
• They argued that the respiratory system
  contributes to stress, but does not define
  syllables.
• Others proposed a role for the laryngeal muscles
  in regulating intensity (loudness an important
  part of stress).
• See Kelso and Munhall (1988) edition of Stetson

49
What is the respiratory contribution to defining
speech prosody?

• But DLWs results are also in question now.
• Finnegan et al. (1999, 2000) measured tracheal
  pressure, laryngeal muscle activity, and airflow.
  
• They showed that the respiratory system
  contributes much more than laryngeal muscle
  activity to both short-term and long-term changes
  in intensity.

Finnegan, Luschei, Hoffmann (1999, 2000) See
advanced reading list for complete reference
50
What is the respiratory contribution to defining
speech prosody?

• Messum (2003) returns to an account like
  Stetsons, but based around the foot rather than
  the syllable (for stress-timed languages like
  English and German). On his account, each foot is
  produced by a single, invariant pulse of effort
  from the muscles of the chest. Speculative but
  interesting, especially in that it tries to
  integrate both developmental and adult physiology
  with speech behaviour

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Summary

• Respiration and laryngeal activity for speech
• are at least as complex as upper articulator
  activity
• interact with upper articulators in complex ways
• have an important role in explaining
• many phonetic phenomena (segments prosody)
• many related linguistic phenomena(grammar,
  meaning)
• a vast range of other communicative phenomena
  (broadly, pragmatic, interactional, and indexical)