The Sensory Systems: Hearing, Taste, Smell, and Touch

A comprehensive set of flashcards covering hearing, taste, smell, and touch based on the lecture notes. Each card follows a question-and-answer format to aid study for the exam.

What are the three characteristics of sound waves and what does each correspond to in perception?

Amplitude (loudness), Frequency (pitch), and Timbre (sound quality).

What is the auditory stimulus in hearing?

Sound waves—vibrations of molecules that travel through a medium such as air.

Name the three sections of the ear and a key component of each.

External ear: pinna and ear canal; Middle ear: ossicles (malleus/hammer, incus/anvil, stapes/stirrup); Inner ear: cochlea and hair cells.

What are the ossicles and their common names?

Malleus (hammer), Incus (anvil), Stapes (stirrup).

What is the function of the oval window in hearing?

Transmits vibrations from the stapes into the cochlear fluid.

Where are hair cells located and on which structure do they sit?

In the cochlea, on the basilar membrane.

What is the basilar membrane’s role in frequency detection?

Supports a traveling wave; peak displacement depends on frequency, creating tonotopic encoding.

What does ‘purity’ of a sound influence, and how does it relate to timbre?

Purity affects timbre (sound quality); two notes at the same pitch on different instruments have different timbre due to purity differences.

What is the traveling wave theory and who proposed it?

Georg von Bekesy’s theory that the basilar membrane moves as a traveling wave with frequency-dependent peak locations.

How do humans locate sounds using the ears?

Sound shadow: time (and sometimes level) differences between the two ears help determine direction.

What are the basic tastes, and which one is sometimes added as an alternative?

Sweet, sour, salty, bitter; umami is sometimes included.

Why is taste considered a chemical sense?

Substances must dissolve in saliva for neural transmission to occur.

Where do taste signals travel after leaving the taste buds?

Thalamus, then to the somatosensory cortex, hypothalamus, and limbic system.

Besides taste buds, what greatly influences our sense of taste?

Smell (olfaction) contributes significantly to flavor perception.

Where are olfactory receptor cells located?

In the olfactory epithelium of the nose.

How long do olfactory receptor cells last?

About 4–8 weeks.

Where does the olfactory nerve project first in the brain?

Directly to the olfactory bulb in the temporal lobes (no thalamic relay first).

Approximately how many odors can humans distinguish?

About 10,000.

What is anosmia?

Loss of the sense of smell.

What is the olfactory epithelium’s role in smell?

Dissolved odor molecules activate olfactory receptor cells in the epithelium.

What is unique about the olfactory pathway to the brain?

Olfactory information reaches the brain directly via the olfactory bulb; some signals go to the limbic system.

Where do some olfactory signals go besides the olfactory bulb?

Hypothalamus and limbic system, contributing to emotional responses to odors.

What is the gate-control theory of pain?

Pain signals can be modulated by other receptors; their activation can open or close a gate to the brain, reducing or amplifying pain.

What are the two main pain pathways?

Fast pathway (localized, quick pain) and slow pathway (less localized, longer-lasting pain).

What is analgia, as mentioned in the notes?

A condition where people can feel pain but cannot react to it.

What factors, besides physiology, can influence pain perception?

Cultural or situational factors.

What is the primary organ of touch?

The skin.

What energy types can activate skin receptors?

Mechanical, thermal, and chemical energy.

Name four major cutaneous receptors.

Pacinian corpuscle, Merkel receptors, Meissner corpuscle, Ruffini endings (Ruffini cylinder).

What are fast and slow pain pathways?

Fast: localized, quick pain; Slow: duller, longer-lasting pain.

What type of nerve endings transmit temperature information?

Free nerve endings for cold and warmth.

What is kinaesthetic sense?

Senses body position and movement via joints, muscles, tendons, and skin; signals go to the somatosensory cortex and cerebellum.

What is the vestibular sense and what structures support it?

Sense of balance/movement; supported by otoliths in the semicircular canals of the inner ear.

Where is the primary organ of balance located?

In the inner ear's semicircular canals (vestibular apparatus).