Physiology - Hearing and Equilibrium

Auricle (Pinna)

External part of the ear that helps localize sound direction.

Tympanic Membrane

Vibrates in response to sound waves.

Ossicles

Malleus, incus, and stapes; transmit sound to the cochlea.

Oval Window

Entrance to the cochlea where stapes transmits vibration.

Scala Vestibuli

Fluid-filled chamber that receives vibration from the oval window.

False

T/F: The cochlea is part of the middle ear.

True

T/F: The tympanic membrane is also called the eardrum.

False

T/F: Sound first strikes the stapes directly from the environment.

True

T/F: The scala tympani connects to the round window.

True

T/F: The pinna helps determine the direction of sound.

Impendance Matching

Ossicles increase pressure to transmit sound to fluid-filled cochlea.

Stapes

Footplate contacts the oval window to transmit sound pressure.

Basilar Membrane

Foundation for the organ of Corti.

Organ of Corti

Main sensory organ of hearing

Helicotrema

Apex where scala vestibuli and scala tympani communicate.

False

T/F: The cochlea contains only two chambers.

True

T/F: The malleus connects directly to the tympanic membrane.

True

T/F: Impedance matching prevents signal loss between air and fluid.

False

T/F: Endolymph is found in scala vestibuli.

True

T/F: Inner hair cells are the primary sensory receptors of hearing.

Amplitude

Determines the loudness of sound.

Frequency

Determines pitch; number of cycles per second (Hz)

Pitch

How high or low a sound is perceived

Timbre

Quality that differentiates sounds of the same pitch/loudness.

Tone

Combination of pitch, loudness, and quality.

False

T/F: High amplitude means low pitch.

True

T/F: Loudness is related to amplitude.

True

T/F: The human ear hears 20 Hz to 20,000 Hz.

False

T/F: Pitch and loudness are the same.

True

T/F: Timbre allows us to differentiate a piano from a guitar.

Tensor Tympani

Middle ear muscle that dampens loud sounds

Stapedius

Smallest skeletal muscle, part of attenuation reflex.

Attenuation Reflex

Reflex that protects ear from loud sounds.

Bone Conduction

Transmission of sound through skull to cochlea.

Masking

Filtering out background noise to focus on useful frequencies.

True

T/F: Bone conduction bypasses the middle ear.

False

T/F: Attenuation reflex amplifies sound.

True

T/F: Stapedius muscle connects to the stapes.

True

T/F: Masking helps us focus on frequencies >1000 Hz.

False

T/F: Attenuation reflex can reduce sound by 5 dB.

Loudness

Perceived sound intensity; affected by amplitude.

Pitch

Sensory interpretation of frequency.

Amplitude

Wave height; affects loudness.

Frequency

Number of wave cycles per second (Hz).

Masking Effect

Suppression of background sounds to prioritize useful signals

False

T/F: A high-frequency sound always has high amplitude.

True

T/F: High amplitude is always loud regardless of frequency.

True

T/F: Low-frequency sounds require more pressure to be heard.

True

T/F: Masking occurs during the attenuation reflex.

False

T/F: Loudness depends solely on frequency.

Auditory Cortex

Processes and interprets sound in the brain.

Broca’s Area

Motor speech production.

Wernicke’s Area

Language comprehension.

Vestibulocochlear Nerve (CN VIII)

Carries sound signals to the brain.

Cochlear Nerve

Transmits impulses from the cochlea to the CNS.

False

T/F: Wernicke’s area is responsible for speech production.

True

T/F: Auditory signals decussate multiple times in the brainstem.

False

T/F: Damage to one auditory cortex eliminates hearing on that side.

True

T/F: Broca’s area damage leads to speech articulation problems.

True

T/F: The cochlear nerve originates from inner ear hair cells.

Time Difference

Sound reaches one ear before the other to localize direction.

Intensity Difference

Louder sound in one ear helps identify source.

Pinna Function

Helps localize vertical and horizontal sound direction.

Olivary Nucleus

Processes binaural auditory cues.

Auditory Cortex

Integrates spatial location of sound.

False

T/F: Sound localization depends only on pitch.

False

T/F: Sounds arrive at both ears at the same time

True

T/F: Olivary nuclei help with timing and intensity comparison.

True

T/F: Pinna contributes to sound localization.

True

T/F: Brain interprets direction based on time and intensity cues.

Weber Test

Assesses lateralization of sound via bone conduction.

Rinne Test

Compares air conduction to bone conduction.

Schwabach Test

Compares patient's hearing to examiner's via bone conduction.

Conductive Hearing Loss

Poor air conduction; bone conduction intact.

Sensorineural Hearing Loss

Poor air and bone conduction.

True

T/F: The Rinne test compares air and bone conduction.

False

T/F: Weber test localizes sensorineural loss to affected ear.

True

T/F: Schwabach test is less commonly used today.

False

T/F: Bone conduction bypasses the cochlea.

True

T/F: Conductive hearing loss shows better bone conduction.

Vestibular Apparatus

Includes semicircular canals and otolith organs.

Utricle and Saccule

Detect linear acceleration and head position.

Semicircular Canals

Detect rotational movement.

Hair Cells

Receptors in vestibular and auditory systems.

Endolymph

Fluid that helps detect motion within semicircular canals.

True

T/F: The utricle detects horizontal movement.

False

T/F: Semicircular canals detect linear acceleration.

False

T/F: Hair cells are found only in the cochlea.

True

T/F: Endolymph flow stimulates hair cells.

False

T/F: Vestibular apparatus is part of the outer ear.

Vestibulo-Ocular Reflex (VOR)

Stabilizes vision during head movement.

Nystagmus

Involuntary eye movement following rapid head motion.

Fast Phase

Direction of nystagmus named after this phase.

Slow Phase

Tracking phase before corrective saccade in nystagmus.

Caloric Test

Stimulates vestibular system using temperature.

False

T/F: Nystagmus always indicates pathology.

True

T/F: VOR helps maintain steady vision while moving.

False

T/F: Fast phase of nystagmus is toward the colder ear.

True

T/F: Caloric stimulation uses temperature to induce eye movement.

True

T/F: VOR is a reflex involving the semicircular canals and eye muscles.