Overview of the Auditory System

Lecture 6

Why is sound important?

Communication, Emotion, Object recognition, 3-D view of the auditory world, Survival

What features of sound are encoded?

Frequency, Intensity, Onset, Duration

What are the features of sound encoded by?

The sensory hair cells and nerve fibres

Define sound frequency

the number of cycles per second (pitch)

What is the range of sound frequency we can hear?

x10³

Define sound intensity

The amplitude of the wave from peak-to-peak (loudness)

What is the unit of measurement for sound intensity?

dB

What is the unit of measurement for sound frequency?

Hz

What is the range of sound intensity can we hear?

x10¹²

Define duration in terms of sound encoding

The ear remaining sensitive to sounds for long periods

List a sound waves journey through the ear

Outer ear, Tympanic membrane, Middle ear (via ossicles), Cochlear, Cochlear nerve (containing ossicles), Brain

What is the first step of sound detection?

1) sound wave funnelled through outer ear to tympanic membrane

What is the second step of sound detection?

2) Crosses middle ear via ossicles

Define ossicles

tiny bones in the middle ear that transmit sounds from tympanic membrane to cochlear

What is the third step of sound detection?

3) sound waves enter the cochlea and are detected by sensory hair cells

What is the fourth step of sound detection

4) The hair cells convert vibrations into electrical pulses that are then transmitted along the cochlear nerve to the brain