Fundamentals of Acoustics and Hearing Science

Vocabulary flashcards covering key terms and concepts from the lecture notes on acoustics and hearing science.

Transverse Wave

Particle movement is perpendicular to the direction of wave propagation.

Longitudinal Wave

Particle movement is parallel to the direction of wave propagation.

X axis

Time

Y axis

Amplitude

Properties required for sound transmission

Mass, Elasticity, Energy source, and a Medium

Inverse Square Law

Intensity decreases proportionally to the square of the distance from the source.

Frequency

Number of cycles per second (Hz).

Period

Time to complete one cycle (seconds).

Amplitude

Magnitude of displacement (dB).

Inertia

Resistance of a mass to change in motion.

Wavelength

Distance between two identical points in a waveform (meters).

Phase angle

Describes the position within a cycle (degrees).

Mass

Quantity of matter (kg).

Elasticity

Ability to return to original shape after deformation.

Oscillation

Repeated back-and-forth movement around an equilibrium.

Fundamental frequency

Lowest frequency of a periodic waveform.

Harmonics

Integer multiples of the fundamental frequency.

Constructive Interference

Waves add to increase amplitude.

Destructive Interference

Waves cancel out or reduce amplitude.

Mechanical resonance

Vibrating system amplifies at natural frequency.

Acoustic resonance

Air in a cavity vibrates in response to sound.

Peripheral and central auditory systems

Work together to convert acoustic signals to neural signals and interpret them.

Outer ear

Acoustic energy.

Middle ear

Mechanical energy.

Inner ear

Hydraulic & Electrochemical energy.

Central auditory system

Electrochemical only.

Utricle & Saccule

Detect linear acceleration and head position (gravity).

Semicircular canals

Detect angular acceleration (head rotation).

Ampulla

Houses the cupula, which bends with endolymph movement.

Otoconia

Calcium carbonate crystals that provide inertia for saccule/utricle.

Vestibulo-ocular reflex

Stabilizes gaze during head movement.

BPPV

Benign Paroxysmal Positional Vertigo - characterized by nystagmus (involuntary eye movement).

Peripheral Auditory System

Outer, middle, inner ear, and auditory nerve.

Central Auditory System

Brainstem and auditory cortex structures.

Pinna

Collects sound, localization, amplifies mid frequencies.

Head shadow effect

Reduction of sound intensity from one side due to head blocking high frequencies.

Tympanic Membrane

A membrane that separates the outer ear from the middle ear.

Ossicular Chain

A chain of three small bones in the middle ear: Malleus, Incus, Stapes.

Oval & Round Windows

Membranes that separate the middle ear from the inner ear.

Eustachian Tube

A tube that connects the middle ear to the nasopharynx, helping to equalize pressure.

Middle Ear Space

The air-filled cavity in the middle ear.

Acoustic Reflex

A reflex that stiffens the ossicles to protect the inner ear from loud sounds.

Surface Area Ratio

The difference in area between the tympanic membrane and the oval window that increases pressure.

Ossicular Lever

A mechanical advantage that increases force in the middle ear.

Cochlea

The part of the inner ear responsible for hearing.

Vestibular System

The part of the inner ear responsible for balance.

Bony Labyrinth

A structure in the inner ear filled with perilymph.

Membranous Labyrinth

A structure in the inner ear filled with endolymph.

Perilymph

Fluid in the bony labyrinth with high Na+ and low K+ concentration.

Endolymph

Fluid in the membranous labyrinth with high K+ and low Na+ concentration.

Modiolus

The central axis of the cochlea.

Scala Vestibuli

One of the three scala in the cochlea.

Scala Media

The middle scala in the cochlea, also known as the cochlear duct.

Scala Tympani

One of the three scala in the cochlea.

Reissner's Membrane

A membrane that separates the scala vestibuli from the scala media.

Basilar Membrane

A membrane that separates the scala media from the scala tympani.

Tonotopic Organization

The arrangement of frequency-specific regions in the cochlea.

Traveling Wave

A wave that varies in height with frequency and intensity in the cochlea.

Organ of Corti

The sensory organ located on the basilar membrane responsible for hearing.

Stereocilia

Hair-like projections on hair cells involved in mechanoelectric transduction.

Depolarization

The process where stereocilia deflect toward the stria vascularis.

Hyperpolarization

The process where stereocilia deflect toward the modiolus.

Type I Auditory Nerve Fibers

Myelinated fibers that connect to inner hair cells.

Type II Auditory Nerve Fibers

Unmyelinated fibers that connect to outer hair cells.

Interaural Time Difference (ITD)

A cue for sound localization based on the time difference of sound reaching each ear.

Interaural Level Difference (ILD)

A cue for sound localization based on the difference in sound level reaching each ear.

Pleural Linkage

The connection between the lungs and thorax that allows lung expansion.

Tidal Breathing

Passive breathing with equal inhale and exhale.

Speech Breathing

Active control of breathing with longer exhalation for speech.

Phonation

The process of sound production via vocal fold vibration.

Bernoulli Effect

The principle that explains how air pressure drop between vocal folds causes suction.

Source-Filter Theory

A theory that describes how the source (glottal sound) and filter (vocal tract resonance) can vary separately.

Spectrograms

Visual representations of the frequency spectrum of sounds.

VOT (Voice Onset Time)

The time between the release of a consonant and the onset of voicing.

Prosody

The rhythm, stress, and intonation of speech.

Hearing Aids

Devices that amplify sound for individuals with hearing loss.

Cochlear Implants

Devices that directly stimulate the auditory nerve to restore hearing.