CSD 4010 - Exam 2

Speech breathing

regulation of breathing for voice and speech production

Vegetative breathing

life-sustaining breathing

Inhalation/inspiration

incoming air

Exhalation/expiration

outgoing air

Tidal volume

the volume of air that is exchanged during any particular cycle or inhalation/exhalation

Diaphragm

large, flat muscle attached at lower border of rib cage; dome-shaped at rest (exhalation) and flattens when it contracts (inhalation)

Inspiratory checking

counteracts the relaxation pressures and promotes the steady lung pressure necessary for phonation; used only when the pressure generated by the lung volume is greater than would be necessary to sustain phonation

Dysfunctional breathing

the disruption of normal breathing patterns occurs in the absence of or in excess to the magnitude of physiological disease

Phonation

generation of speech sounds by vibration of VF

Vocal quality

listener's perception of the voice

Pitch

perceptual correlate of fundamental frequency

Glottis

space between the true VF

Stress

perpendicular force on the VF

Strain

parallel force on the VF

Phonation onset

the initiation of phonation divided into three categories: simultaneous, breathy, and glottal attack

Jitter

a measure of cycle-by-cycle variability in frequency

Shimmer

the variation in amplitude of a sound wave or intensity of vocal emission

Resonance

the process by which an object is made to vibrate by absorbing energy at its natural frequencies; the cavities of resonance include the larynx, pharynx, oral cavity, nasal cavities, and sinuses

Boyle's Law

as the volume of a container increases, air pressure within the container (lungs) decrease (& vice versa); the negative pressure in the thoracic cavity causes the air from the atmosphere to flood into the lungs

Lung pressure

the force of subglottal air on VF

- key in regulation of intensity and frequency control

- increased lung pressure = larger amplitude

- larger volume of air = larger acoustic power

- greater effect at lower frequencies than higher

- a manometer is used to measure lung pressure

Lung volume

tidal volume (TV)

inspiratory reserve volume (IRV) - the amount of air that could be inhaled

expiratory reserve volume (ERV) - the amount of air that could be exhaled

residual volume (RV) - the volume of air that remains in the lungs after max exhalation

Pleural Iinkage

the visceral pleura surrounds the lungs, parietal pleura lines the inside of the thorax (NOT 2 separate membranes - continuous); acts as a surfactant between membranes to help achieve negative pressure (and in turn inhalation)

Forced inhalation and expiration

forced inhalation - above 60% of vital capacity; helps to engage more musculature, supports physical exertion, supports effortful speech, uses more air than tidal breathing

forced exhalation - greater air expired than in tidal breathing; internal intercostals and abdominal muscles are involved, active process

Airway resistance

due mainly to the diameter of the airways (airflow has an inverse relationship to resistance)

- narrow = more resistance

- wider = less resistance

influenced by lung volume, the upper airway (nose, pharynx, and larynx), & the nervous system (sympathetic widens the airway, parasympathetic constricts the airway)

smooth, unobstructed airflow is laminar, but our airway is turbulent

Airway humidification

the major purpose of the upper airway is to condition the air (add humidification & remove pollutants)

turbinates (folds of tissue in the nose) are covered in vascular mucosal tissues which condition the air we breathe in

asymmetric breathing - works to warm and humidify

mouth breathing can dehydrate the mucosal lining of the airway and VF compared to nose breathing

Structural framework of larynx

Innervation of the larynx

CN X - Vagus; recurrent laryngeal nerve

Extrinsic muscles of larynx - purpose

suprahyoid muscles

digastric - elevates hyoid

geniohyoid - moves tongue and hyoid anteriorly

mylohyoid - elevates hyoid, depresses mandible

stylohyoid - elevates and retracts hyoid

infrahyoid muscles

thyrohyoid - depresses hyoid, elevates thyroid

sternohyoid & sternothyroid - depresses hyoid

omohyoid - depresses and retracts hyoid

Intrinsic muscles of larynx - function

abductor

- posterior cricoarytenoid (sole abductor of VF)

adductors

- oblique arytenoid

- transverse arytenoid

- lateral cricoarytenoid

tensors/relaxers

- thyroarytenoid - relaxes the vocal ligament

- cricothyroid - stretches & tenses the vocal ligament

3 functions of the larynx

1. protecting the lungs from intruders (coughing, throat clearing)

2. participates in breathing (widens/decreases airway lumen to decrease/increase resistance)

3. stabilizes torso (lifting, pushing/pulling, VF seal airway thereby fixing thorax)

Lamina propria - layers

multi layered membranes, each layer having different biomechanical properties

1. most superficial layer - loosely arranged elastin fibers

2. intermediate layer - densely distributed elastin fibers

3. deep layer - tightly packed collagen fibers

3 laryngeal valves

1. aryepiglottic muscle – most superior; runs from sides of epiglottis to top of each arytenoid cartilage, contracts in a circular action to pull epiglottis backwards and close entrance of larynx during swallow

2. ventricular folds (false vocal cords) - superior and parallel to TVC, limited movement, close during swallowing but open during phonation, ventricle separates TVC from FVC

3. true vocal cords (TVC) - epithelium, lamina propria, vocalis/thyroarytenoid muscle

Joints of the larynx

cricoarytenoid joints – allows the arytenoids to glide medially (close), laterally (open), and rock forwards and backwards (tighten)

cricothyroid joints – regulates fundamental frequency (pitch) by elongating and shortening the vocal folds (tension)

Bernoulli Effect

an increase in velocity = decrease in pressure

- conservation of energy

- critical in VF vibration and voice production

- fluid flows faster through narrower sections

Myoelastic-Aerodynamic Theory

myoelastic - physical properties of VF, particularly elasticity, mass per unit length, and tension

tension is the force used to elongate the VF; the result of the pulling force exerted upon the VF and their resistance to that force (stiffness)

aerodynamic - Bernoulli effect

Voice quality

sum of both laryngeal influences and influences of the vocal tract (mode of vibration)

laryngeal influences:

- breathy voice

- pressed voice

Fundamental frequency measures

- habitual use

- maximum performance (physiological limits of the voice)

- degree of regularity (jitter)

Intensity measures

- habitual intensity level

- physiological range

- amplitude (shimmer)

Measure of phonatory aerodynamics

(airflow)

- lung pressure

- vocal efficiency

- laryngeal airway resistance

Fundamental frequency

the rate of vibration of the VF

controlled by length, tension, and stiffness

Maximum phonation time

deep breath, sustain a vowel as long as possible

15-25 seconds in healthy adults

detects impairments of phonatory glottal closure

Control of intensity

major determinants:

- lung pressure (except at high frequencies)

- VF closure

- vocal tract resonance

Biomechanical forces - stress

VF can stretch more than a muscle & builds up stress faster than muscles

Driving pressure

difference between high and low pressure areas that causes air to flow between these areas; created in the ventricles