Audition

Question 1

Auditory Mechanisms in Diff Species

Answer 1

Species vary in the range of frequencies they can detect

Question 2

Basilar Membrane

Answer 2

• Contains hearing receptors
• Varies in length across species
• Longer = wider range of frequencies (mammals have longest)
• Widens towards apex

Question 3

Stimulus - Sound Waves

Answer 3

• Vibrations in air particles
• Condensed bands of air particles ripple away from sound source
• Needs a sound source
• Sound travels faster in liquids and solids

Question 4

Sound waves are ______

Answer 4

Longitudinal (vibrate parallel)

Question 5

Amp, Wavelength, Purity

Answer 5

Amplitude = Loudness (high amp, louder)
Wavelength = Pitch (short = high pitch, long = low pitch)
Purity = Timbre

Question 6

External Ear

Answer 6

Changes Air Pressure

Question 7

Pinna

Answer 7

Cone-shaped protuberances on the side of your head
- Collect sound waves, directs them into ear canal

Question 8

Ear Canal

Answer 8

Narrowing tube in the outer ear that connects the outside world to the middle ear in the tympanic membrane
- Amplifies sound waves

Question 9

Tympanic Membrane

Answer 9

thin membrane vibrating at the end of the ear canal
- Separates outer and middle ear

Question 10

Ossicles

Answer 10

Stirrup, anvil, hammer
- Amplifies sounds

Question 11

Where does air pressure get converted to soundwaves

Answer 11

fluid filled inner ear

Question 12

Inner Ear

Answer 12

Detect change in fluid pressure

Question 13

Cochlea

Answer 13

Connected to oval
- contains neural tissue for transferring changes in fluid motion to neural impulses

Question 14

Oval window

Answer 14

small opening in side of cochlea

Question 15

Vibrations in Basilar Membrane

Answer 15

Low frequency sound = long wavelength = ending near apex of the membrane
High frequency sound = small wavelength = one cycle will end near the base

Question 16

Hair Cells

Answer 16

When hair cells are displaced by vibration, they convert the frequency of sound into electrical signal

Question 17

Electrical signal in hair cells

Answer 17

Mechanical displacement of hair cells = (+) ions from extracellular fluid enter body of cell
- Loudness affects bending, # of (+) ions in neuron
- Rush of (+) ions reach threshold, cell depolarizes = AP

Question 18

Outer Hair cells

Answer 18

• More numerous 4:1
• Fewer connections to brain
• Share one direct link to brain with 30 other outer hair cells
• Amplify sound
• Unmyelinated

Question 19

Inner Hair Cells

Answer 19

Less numerous 1:4
- More connections to brain; 20
- Send pitch information
- Myelinated

Question 20

Auditory Localization

Answer 20

Depends on interaural differences between ears

Question 21

Interaural Time Difference

Answer 21

Changes depending on direction of incoming sound
- Specific neurons in superior olivary complex respond

Question 22

Head Shadow Effect

Answer 22

If wavelength is larger than diameter of listeners head; soundwave can diffract around the head without losing intensity

Question 23

What sound frequency does not cast a shadow

Answer 23

low

Question 24

Superior Olivary Complex

Answer 24

respond to intensity differences from each ear

Question 25

What would make it hard to locate sound

Answer 25

If it’s directly in front or behind you

Question 26

Interaural Intensity Difference

Answer 26

Auditory cue resulted from a difference in sound intensity bw ears

Question 27

Echolocation

Answer 27

where a receiver emits sound pulses and analyses the returning echo; forming a perceptual image of objects in the environment

Question 28

Co-evolution

Answer 28

Process by which evolution and adaptation of traits of one species can directly affect the evolution of traits in other species

Question 29

Absolute Pitch

Answer 29

ability to identify a pitch without reference to an external source