Sensation & Perception – Auditory, Vestibular, Somatosensory, Taste, and Olfaction

110 Question-and-Answer flashcards spanning auditory, vestibular, somatosensory, taste, and olfactory systems, aligned with lecture notes for comprehensive exam review.

What are auditory signals sensed as?

Periodic compressions of air, water, or other media.

How do humans experience hearing?

By detecting sound waves.

What are sound waves?

Periodic compressions of air, water, or other media.

In sound, what does amplitude refer to?

The intensity (loudness) of the sound wave.

What is frequency in sound?

The number of compressions per second, measured in hertz (Hz).

To what perceptual quality is frequency related?

Pitch (high versus low).

Pitch is primarily related to .

Frequency.

What is timbre?

Tone quality or tone complexity.

Why do children hear higher frequencies than adults?

High-frequency sensitivity diminishes with age and loud-noise exposure.

How do people communicate emotion in speech?

Through alterations in pitch, loudness, and timbre.

What are the three main sections of the ear?

Outer ear, middle ear, and inner ear.

What structures make up the outer ear?

The pinna—flesh and cartilage attached to each side of the head.

What is the function of the pinna?

Alters reflection of sound waves and helps locate a sound’s source.

What does the middle ear contain?

The tympanic membrane and three tiny bones (malleus, incus, stapes).

What is the tympanic membrane?

The eardrum; it vibrates at the same rate as incoming sound waves.

What is the purpose of the middle-ear bones?

Transform vibrations into stronger waves for the oval window.

What is the oval window?

A membrane in the inner ear that transmits waves through fluid.

What is the cochlea?

A snail-shaped inner-ear structure with three fluid-filled tunnels.

Name the three tunnels of the cochlea.

Scala vestibuli, scala media, and scala tympani.

What are hair cells (in hearing)?

Auditory receptors between the basilar and tectorial membranes.

How do hair cells excite the auditory nerve?

Vibrations displace them, opening ion channels that trigger impulses.

What is the place theory of pitch perception?

Different places on the basilar membrane respond to different frequencies.

What is the frequency theory of pitch perception?

The entire basilar membrane vibrates in synchrony with sound frequency.

What is the modern (current) theory of pitch perception?

A combination of place and frequency theories.

What is the volley principle?

Auditory nerve produces volleys of impulses up to ~4000 per second.

Why is coordination necessary in the volley principle?

No single axon can fire fast enough alone to code high frequencies.

What is amusia?

Impaired detection of frequency changes (tone deafness).

What brain features are found in people with amusia?

Thicker right auditory cortex and fewer connections to frontal cortex.

What is absolute pitch?

Ability to identify or produce a note without external reference.

What factors influence absolute pitch?

Genetics, early musical training, and speaking tonal languages.

Where is the primary auditory cortex (A1) located?

The superior temporal cortex.

What is area A1 responsible for?

Receiving most auditory input and supporting auditory imagery.

How is the auditory cortex organized?

Like the visual cortex, with motion detection and tonotopic maps.

What happens to A1 in those deaf from birth?

Its axons develop less extensively.

What is a tonotopic map?

Spatial arrangement of neurons each tuned to a preferred tone.

Does damage to A1 always cause deafness?

Not unless damage extends to subcortical auditory areas.

What do surrounding auditory areas process?

Auditory objects such as music, machinery, or animal cries.

What are the two major types of hearing loss?

Conductive (middle-ear) deafness and nerve (inner-ear) deafness.

What causes conductive deafness?

Failure of middle-ear bones to transmit sound; often treatable.

What causes nerve deafness?

Damage to the cochlea, hair cells, or auditory nerve.

What is tinnitus?

Persistent ringing in the ears, often related to nerve deafness.

Tinnitus is linked in the brain to __.

Auditory areas receiving input from other body parts (phantom-limb-like).

Why do many older adults struggle with auditory attention?

Reduced inhibitory neurotransmitter activity in auditory areas.

What strategy can help older adults hear better in conversation?

Watching the speaker’s face (visual cues).

Name the three primary cues for sound localization.

Sound shadow, time of arrival, and phase difference.

How are high-frequency sounds localized?

By sound shadow and loudness differences between ears.

How are low-frequency sounds localized?

By interaural phase differences.

Which sounds rely mainly on time-of-arrival cues?

Sudden-onset sounds.

For what frequency range is the sound shadow most effective?

Approximately 2000–3000 Hz.

Phase-difference cues work best up to about Hz.

1500 Hz.

What is the vestibular sense?

The system that detects head position and movement.

What structures make up the vestibular organ?

The saccule, utricle, and three semicircular canals.

What do semicircular canals detect?

Direction and acceleration of head movements.

What do the otolith organs (saccule & utricle) detect?

Head tilt direction and linear acceleration.

What triggers vestibular action potentials?

Movement of jelly-like fluid and otoliths over hair cells.

Where do vestibular nerves project?

To the brainstem and cerebellum.

What does the somatosensory system detect?

Touch, pressure, cold, warmth, pain, itch, and body position.

Name three types of somatosensory receptors.

Bare neuron endings, encapsulated receptors, stretch receptors.

What do free nerve endings respond to?

Pain, warmth, and cold.

What do Merkel discs detect?

Light touch (hairy and glabrous skin).

What do Pacinian corpuscles detect?

Deep pressure and vibration.

What do Ruffini endings respond to?

Skin stretch.

Define dermatome.

Skin area innervated by a single spinal nerve.

Outline the basic somatosensory pathway.

Receptors → spinal cord → thalamus → primary somatosensory cortex.

Where is the primary somatosensory cortex located?

In the parietal lobe.

What is pain?

An unpleasant sensation signaling tissue damage.

Name three chemicals that increase pain sensitivity.

Histamine, prostaglandins, and nerve growth factor (NGF).

Which structures transmit pain signals?

Bare nerve endings carried by A-delta and C fibers.

What are A-delta fibers?

Myelinated axons transmitting sharp, localized pain quickly.

What are C fibers?

Unmyelinated axons transmitting dull, aching pain slowly.

Which brain regions respond to pain intensity?

Somatosensory cortex and anterior cingulate cortex.

What is the gate theory of pain?

Non-painful input in the spinal cord can inhibit pain signals.

What are endorphins?

Brain-produced opiates that reduce pain.

How do opioids reduce pain?

They bind to receptors in the brain and spinal cord.

What is naloxone?

A drug that blocks opiate receptors and reverses opioid effects.

What is referred pain?

Pain perceived at a location other than its source.

What causes itch?

Mild tissue damage, histamine release, or certain chemicals.

How do pain and itch interact?

Each can inhibit the other; scratching (pain) reduces itch.

What is a chemical sense?

Detection of chemicals (taste and smell).

Define taste (gustation).

Sense that detects substances dissolved in saliva.

What are taste buds?

Receptors on the tongue that detect basic tastes.

What are papillae?

Tongue structures that house taste buds.

Approximately how many taste buds do humans have?

About 5,000–10,000.

List the five basic tastes.

Sweet, sour, salty, bitter, and umami.

What does salty taste detect?

Sodium ions.

What does sour taste detect?

Acids (H⁺ ions).

What does sweet taste detect?

Sugars.

What does bitter taste often signal?

Potential toxins (alkaloids).

What does umami detect?

Glutamate and other amino acids (savory).

Which cranial nerves carry taste information?

Facial (VII), glossopharyngeal (IX), and vagus (X).

Where do taste signals first synapse in the brain?

Nucleus of the tractus solitarius (NTS) in the medulla.

What is the insula?

The primary taste cortex.

What is the labeled-line theory of taste?

Each receptor sends a direct line for its particular taste.

What is the across-fiber pattern theory?

Taste depends on the overall activation pattern across receptors.

Define olfaction.

The sense of smell—detection of airborne chemicals.

Where are olfactory receptors located?

In the olfactory epithelium of the nasal cavity.

To what do olfactory receptors respond?

Specific chemicals binding to their receptor sites.

Roughly how many types of olfactory receptors do humans have?

About 350 functional types.

Where do olfactory receptor axons project first?

To the olfactory bulb.

What is the olfactory bulb?

Brain structure receiving input from olfactory receptors.