Structure and Function of the Auditory System

These flashcards cover key vocabulary terms and concepts related to the structure and function of the auditory system as presented in the lecture notes.

Auditory periphery

The outer ear, middle ear, and inner ear, ending at the nerve fibers exiting the inner ear.

Auditory central nervous system

The ascending and descending auditory pathways in the brainstem and cortex.

Tonotopic organization

The systematic mapping of sound frequency to the place of maximum stimulation within the auditory system.

Frequency

The measure of how high or low a sound is; often referred to as pitch.

Transducer

A device that converts one form of energy to another; for example, the cochlea converts mechanical vibrations to electrical energy.

Pinna

The outer part of the ear that helps to collect sound waves.

Tympanic membrane

The eardrum; a membrane that vibrates in response to sound waves.

Ossicles

The three small bones in the middle ear: malleus, incus, and stapes.

Eustachian tube

A tube that connects the middle ear to the nasopharynx; helps to equalize pressure.

Cerumen

Ear wax; protects the ear canal and helps in cleaning and lubrication.

Acoustic gain

The increase in sound pressure level as sound travels through the ear.

Resonant frequency

The frequency at which a system naturally vibrates.

Cochlea

The spiral-shaped organ in the inner ear responsible for sound transduction.

Scala media

The cochlear duct that contains endolymph fluid and houses the organ of Corti.

Basilar membrane

A membrane in the cochlea that moves in response to sound waves, enabling sound transduction.

Organ of Corti

The sensory organ of hearing located within the cochlea; contains hair cells.

Inner hair cells

Sensory cells in the cochlea that help transmit sound information to the auditory nerve.

Outer hair cells

Cells that enhance the sensitivity of hearing by amplifying sound vibrations.

Traveling wave

The wave of fluid movement in the cochlea caused by the stapedial footplate's movement.

Cochlear microphonic

An alternating current potential produced by hair cell activity in response to sound.

Action potential

A rapid rise and fall in voltage or membrane potential across a cellular membrane.

Summating potential

A steady-state potential related to ongoing stimulation that reflects a continuous response.

Auditory nerve

The cranial nerve responsible for transmitting sound signals from the cochlea to the brain.

Cerebellopontine angle

The region where the auditory nerve attaches to the brainstem.

Superior Olivary Complex (SOC)

A structure in the brain responsible for processing auditory information and localizing sound.

Medial Geniculate Body

Part of the thalamus that processes auditory information before it reaches the auditory cortex.

Inferior Colliculus

A midbrain structure that acts as a principal auditory center in the brain.

Lateral Lemniscus

A tract in the brain that carries auditory signals to the superior olivary complex.

Temporal lobe

The lobe of the brain that contains areas responsible for processing auditory information.

Acoustic reflex

A muscle reflex that occurs in response to loud sounds to protect the inner ear.

Impedance mismatch

The difference in acoustic impedance between air and fluid that affects sound transmission.

Oval window

The membrane-covered opening that leads from the middle ear to the inner ear.

Round window

A membrane that allows for fluid movement in the inner ear in response to sound.

Acoustic gain (dB)

The measurement of sound amplification through various structures of the ear.

Umbo

The most central point of the tympanic membrane (eardrum) where vibrations occur.

Pars tensa

The taut section of the tympanic membrane that moves in response to sound.

Pars flaccida

The part of the tympanic membrane that is less taut and more flexible.

Tectorial membrane

A membrane in the cochlea that interacts with hair cells to facilitate sound transduction.

Helicotrema

The opening connecting the scala vestibuli and scala tympani in the cochlea.

Basilar membrane

The membrane in the cochlea that supports the organ of Corti and is involved in sound detection.

Neural response

The electrical response from auditory hair cells that leads to the perception of sound.

Cochlear amplifier

The mechanisms that enhance sound sensitivity in the cochlea, primarily through outer hair cell motion.

Character frequency

The frequency at which a specific auditory nerve fiber is most responsive.

Nerve fibers

Projections from sensory cells that carry electrical signals to the brain.

Vestibular system

The part of the inner ear responsible for maintaining balance and spatial orientation.

Crista

Sensory structures in the ampulla of the semicircular canals that detect angular acceleration.

Saccule

A structure in the inner ear that contributes to the sense of balance and equilibrium.

Utricle

Similar to the saccule, it helps with balance and is involved in detecting linear motion.

Proprioception

The sense that informs the brain about the position and movement of the body.

Afferent fibers

Nerve fibers that carry sensory information towards the brain.

Efferent fibers

Nerve fibers that carry signals away from the brain to effectors.

Acoustic stimuli

Sounds that create responses in the auditory system.

Frequencies

The different rates of sound waves that correlate with pitch and tone.

Sound localization

The ability to identify the location or direction of a sound source.

Elevation of sound source

The perception related to where a sound is originating from in the vertical plane.

High-frequency sounds

Sounds at a higher pitch which are typically more crucial for understanding speech.

Cochlear nucleus

The brainstem nucleus that receives input from the auditory nerve.