MCAT Sensory Processing & Auditory Physiology Study Guide

A set of vocabulary flashcards covering the physiological mechanisms of vision and audition, including neural pathways, mechanotransduction, and medical interventions like cochlear implants.

Parvocellular Pathway

A visual processing pathway specialized for high spatial resolution (fine detail, form, and color) but having low temporal resolution.

Magnocellular Pathway

A visual processing pathway specialized for high temporal resolution and motion detection, characterized by poor spatial resolution and a lack of color perception.

Tympanic Membrane

Commonly known as the eardrum, this structure converts incoming pressurized sound waves into mechanical vibrations.

Ossicles

The three tiny bones of the middle ear—Malleus (hammer), Incus (anvil), and Stapes (stirrup)—that amplify mechanical vibrations.

Oval Window

The membrane-covered opening to the cochlea that the stapes pushes against to move cochlear fluid.

Scalae (Vestibuli and Tympany)

Chambers in the cochlea; fluid enters the scala vestibuli through the oval window and exits through the scala tympani via the round window.

Helicotrema

The opening at the apex of the cochlea where the scala vestibuli and scala tympani meet.

Organ of Corti

The receptor organ for hearing located inside the cochlea, containing the basilar membrane, tectorial membrane, and hair cells.

Tip Links

Tiny protein filaments connecting adjacent kinocilia/stereocilia that mechanically pull open gated ion channels when stretched by fluid movement.

Hair Cell Depolarization

Process where mechanical stretching of tip links allows $K^+$ influx from endolymph, opening voltage-gated $Ca^{2+}$ channels and triggering neurotransmitter release.

Spiral Ganglion Cells

Bipolar neurons whose dendrites innervate cochlear hair cells and whose axons form the auditory nerve.

Basilar Tuning

The spatial arrangement of the basilar membrane where high frequencies stimulate the stiff, narrow base and low frequencies stimulate the flexible, wide apex.

Tonotopic Mapping

The preservation of the spatial frequency arrangement from the basilar membrane within the primary auditory cortex.

Sensorineural Deafness

Also known as "nerve" deafness, this condition is caused by non-functional hair cells despite an intact auditory nerve.

Speech Processor

A component of a cochlear implant that converts environmental sound into digitized electrical signals.

Stimulator (Cochlear Implant)

The component of a cochlear implant that bypasses damaged hair cells to send electrical impulses down an electrode array into the cochlea to stimulate the auditory nerve.