Midterm part 1/2 Flashcards
Neurons: definition, parts, basic function
-the neuron, or nerve cell, is the basic unit of the nervous system
-a nerve is a collection of neurons that serves a particular part of the body
Properties:
-3 main parts: a cell body plus projections–dendrites + axons
-axons carry information away from the cell body (efferent)
-dendrites receive info from other nerve cells, transmit them to the cell body
CNS: The Sensory Strip: location
-located in parietal lobe
CNS: The Motor Strip: location
-located in frontal lobe
CNS: Motor and Sensory Strips: basics
- representation is upside down in motor and sensory strip: head at bottom, lower limbs at top
- large amounts of the cortex are devoted to the hands and oral (speech) mechanism, because they are essential to receiving environmental information and acting on it
Role of PNS in Speech Production
motor units in here too
- muscles innervated by cranial nerves lie in the head and neck
- respiratory system is innervated by spinal nerves
- efferent impulses innervate w/ muscles in motor units
- motor unit: single motor neuron and the muscle fibers it serves
- related to efferent neurons (nerves that take info from CNS to body)
- action potential at motor unit stimulates muscle fibers
Phonation: what is it?
- when air pressure forces the vocal folds to vibrate
- phonation is used in the production of vowels
- results in a periodic sound wave
Respiratory Volumes: Tidal Volume (TV)
amount of air exchanged (in and out) during a cycle of quiet breathing
Respiratory Volumes: Vital Capacity (VC)
amount of air exchanged in maximum inspiration and expiration cycle
-respiratory volumes are often expressed as a percentage of VC
Respiratory Volumes: Residual Volume (RV)
air that cannot be expelled from lungs
Respiratory Volumes:
Inspiratory Reserve Volume (IRV)
volume that can be inspired beyond a restful inspiration
Respiratory Volumes:
Expiratory Reserve Volume (ERV)
volume that can be expired beyond a restful expiration
Boyle’s Law:
- what is it?
- how does it work with inspiration and expiration?
-relationship between volume and pressure
- inspiration: increase in thoracic volume causes a decrease in thoracic pressure
- the result is air rushes in
- expiration: decrease in thoracic volume causes an increase in thoracic pressure
- the result is air rushes out
How Do Speech Breathing and Quiet Breathing Differ?
- Exhalation is slower in speech breathing, takes up more of the cycle
- -speech breathing: 10% spent inhaling, 90% out
- -quiet breathing: 40% in, 60% out
- Control is more voluntary and conscious in speech breathing, where quiet breathing is reflexive
The 3 Passive Forces of Exhalation/Expiration
- elastic recoil of the lungs and rib cage
- the force of the untwisting of the cartilages next to the sternum (detorque)
- gravity
(think about how these interact w/ boyle’s law)
Clinical Populations and Respiratory Control
- Voice Disorders: improper laryngeal valving may waste exhaled air
- Severe Hearing Impairment: poor laryngeal control due to abnormalities of the vocal folds may waste air
- Motor Speech Disorders: may affect respiratory muscle coordination
Types of Speech-Sound Production: Periodic and Aperiodic Sound Waves
- phonation creates nearly periodic sound by rapid opening and closing of vocal chords
- consonant production - aperiodicity created when the articulators obstruct the air flow
Vocal Folds:
What they’re made of, where they are, properties and pitch
- elastic bands of tendon, muscles, and mucous membrane
- lie behind thyroid cartilage
- tension and elasticity vary: can be made thicker or thinner, longer or shorter
- human larynx allows for these adjustments
- person’s voice pitch is determined by the resonant frequency of the vocal folds
Vocal Folds:
Myoelastic Aerodynamic Theory
- the myoelastic aerodynamic theory states that the vocal folds are activated by the airstream from the lungs rather than by nerve impulses
- myo- = muscles, they adduct vocal folds, establish levels of tension and elasticity
- elasticity = allows vocal folds to stretch and return in each cycle
- aerodynamic = subglottal pressure from the lungs drives vibration
- air pressure from the lungs drives the VFs apart and opens the glottis during each vibration
Vocal Folds:
Cover-Body Model
-explains how the structure of the VFs accounts for the wide range of frequencies, amplitudes and vocal qualities that can be produced by phonating
Larynx:
Functions (5)
- controls airflow in + out of lungs: provides O2, eliminates CO2
- prevents food, water, and other substances from being aspirated into the lungs
- increases intrathoracic pressure during vomiting, coughing, lifting, etc
- aids in swallowing
- provides sound source for speech
Larynx:
Structure
(parts of the larynx, where they are relative to each other)
- larynx lies below hyoid bone at top of trachea
- hyoid bone: between larynx and jaw
- thyroid cartilage: encloses the larynx anteriorly, lies anterior to the arytenoid cartilages
- cricoid cartilage: top ring of trachea, supports arytenoids
- arytenoid cartilages: paired pyramidal structures, vocal processes (small projection at base of each arytenoid cartilage) run forward to attach to vocal folds
Posterior Cricoarytenoid Muscles (PCA)
- posterior cricoarytenoid muscles (PCA)
- attachments: arytenoid cartilages, dorsal plates of cricoid cartilages
- rotate arytenoids and separate vocal folds
- purpose: abduct the folds so air can pass from the lungs to the oral cavity
- PCA is the only vocal fold abductor
Interarytenoid Muscles
- interarytenoid muscles (IA)
- transverse IA runs horizontally between arytenoids
- Oblique IA connects arytenoids in X-shape
- Draws arytenoids together posteriorly and adducts vocal folds
- Purpose: To adduct the VFs for vibration – phonation
- IA is the primary VF adductor
Lateral Cricoarytenoid muscles (LCA)
- attachments: muscular process of arytenoid cartilages, lateral margins of cricoid cartilage
- draw arytenoids forward and down
- assist in ADDUCTION
- IA and LCA muscles work together for strong adduction of vocal folds– i.e. vowel production
