Unit 2-3

Question 1

The sense of hearing

Answer 1

Detecting vibrations in the air

Question 2

Amplitude

Answer 2

Vertical height from peak to trough

Question 3

Wavelength

Answer 3

Horizontal distance from peak to peak or trough to trough

Question 4

Frequency

Answer 4

Inversely proportional to wave— the shorter the waves are, the faster they pass by

Question 5

Ultrasound

Answer 5

Frequencies above (20,000/20KHz) (bats, porpoises)

Question 6

Infrasound

Answer 6

Below 20Hz (elephants, whales)

Question 7

External ear

Answer 7

Captures and focuses sound

Question 8

External ear properties

Answer 8

1. Pinnae (ear)
2. Ridges and valleys of pinnae enhance some sounds and filter others
3. Auditory canal (ear canal)

Question 9

Middle ear

Answer 9

Concentrates sound energy

Question 10

Middle ear properties (4)

Answer 10

1. Tympanic membrane (vibrates at same frequency as incoming)
2. Ossicles (three tiny bones that vibrate in response to tympanic membrane) (malleus/hammer, incus/anvil, stapes/stirrup)
3. Ossicles vibrate against oval window (membrane that borders the inner ear) (amplifies sound by concentrating vibrations in the larger tympanic membrane to a smaller area)
4. Volume control (two tiny muscles stiffen the flexibility of the ossicles) (controlled by brain from onset of sound, and when about to vocalize)

Question 11

Inner ear properties (4)

Answer 11

1. Cochlea (3 canals: vestibular, middle, tympanic)
2. Middle canal = organ of corti (transduces sound into neural activity)
3. Organ of corti membranes (tectorial and basilar)
4. Between membranes = hair cells -> auditory receptors

Question 12

Hair cells respond to (4)

Answer 12

Vibrations in the basilar membrane

• lined with stereocilia
• basilar membrane vibrates —> ion channels are mechanically forced open as stereocilia are bent
• channels let in Na+ and Ca+, depolarization
• vestibulocochlear nerve carries the signal back to brain

Question 13

pathway to primary auditory cortex (A1)

Answer 13

• located at top of temporal lobes
• contains tonotopic map frequencies
• activation of one frequency tends to inhibit activity of receptors and neighboring frequencies, sharpening our ability to discern pitch

Question 14

Localizing sound

Answer 14

• interaural (between ears) differences
• requires binaural input (both ears)

Question 15

Spectral filtering

Answer 15

• Pinnae enhances some frequencies and dampens others.

Question 16

Hearing loss

Answer 16

Moderate to severe decrease in sensitivity to sound

Question 17

Deafness

Answer 17

Hearing loss so profound, that speech cannot be perceived, even with hearing aids

Question 18

Conduction deafness

Answer 18

Problem with sound getting to inner ear

Question 19

Sensorineural deafness

Answer 19

Problems turning sound into action potentials (also expose to too much loud noise)

Question 20

Central deafness

Answer 20

Problems with processing sound in the cortex

Question 21

Cochlear implants

Answer 21

Detect sounds, and transmit them to the auditory nerve

Question 22

Vestibular system

Answer 22

• Senses directional movement/ balance
• composed of three semicircular canals that reside inside hollow space of the temporal bone

Question 23

Pitch

Answer 23

Up and down

Question 24

Yaw

Answer 24

Turn side to side

Question 25

Roll

Answer 25

Bend left and right

Question 26

Transduction of motion and balance

Answer 26

• Hair cells —> movement of head causes fluid inside canals to flow,
  bending hair cells, and signaling movement
• Sensory info from vestibular system carried by vestibulocochlear
• Info is sent to areas important for planning and control of movement
• some terminate in vestibular nuclei and go to motor areas, others go straight to the cerebellum

Question 27

Motion sickness

Answer 27

• Nausea brought on by movements you were not controlling.
• Conflict between sensory information from vestibular and other sensory modalities, including vision. (Ears sense movement but eyes are focused)

Question 28

Vertigo

Answer 28

Sensation of whirling, dizziness, or loss of balance. Damage to vestibular system.

Question 29

Alcohol

Answer 29

High BAC changes density of the fluid in the semicircular, canals, increasing the sensitivity to movements

Question 30

Inner ear

Answer 30

Transduces sound into neural activity