Auditory pathways

Question 1

What are the functions of hearing?

Answer 1

1. respond to sounds appropriate for survival
2. appreciate natural and man made sounds in environment
3. understand the speech of others
4. acquiring skills to speak clearly and effectively

Question 2

Where is sound perceived?

Answer 2

The auditory cortex of the temporal region of the brain

Question 3

How is the primary auditory cortex arranged?

Answer 3

Tonotopically - neirons responding to low frequencies are situated anteromedially, and those responding to high frequencies posterolaterally

Question 4

What is the function of the secondary auditory complex?

Answer 4

Imp for the localisation and analysis of complex sounds, and in auditory memory

Question 5

What is the role of the auricle/pinna?

Answer 5

Collects and directs sound waves

Question 6

What is the role of the external auditory meatus?

Answer 6

Transmits sound waves deep into the skull to the tympanic membrane

Question 7

What is the middle ear?

Answer 7

An air filled chamber connected to the pharynx by the Eustatian tube which contains the auditory ossicles

Question 8

What are the names of the auditory ossicles?

Answer 8

1. malleus
2. incus
3. stapes

Question 9

What is the role of the auditory ossicles?

Answer 9

Carry sound vibrations from the tympanic membrane to the inner ear

Question 10

What is the inner ear?

Answer 10

A bony fluid-filled chamber

Question 11

Where does the middle ear join the inner ear?

Answer 11

At the oval window

Question 12

How is sound info passed from the middle ear to the inner ear?

Answer 12

1. oval window receives vibration form the stapes bone
2. vibrations travel through fluid in cochlear
3. activate the tiny hairs on the end of nerve cells which fires an action potential

Question 13

Where do nerve impulses from the cochlea and vestibule travel?

Answer 13

Along the vestibulocochlear nerve to the brainstem

Question 14

What are the different ways that sound info is interpreted?

Answer 14

1. frequency (pitch)
2. intensity
3. duration
4. location (where is the source)

Question 15

What does the vesibulocochlear nerve pass sound info to?

Answer 15

1. the cochlear nuclei in the medulla near the junction with the pons
2. info from each ear reaches the cochlear nuclei at the same time

Question 16

What does the cochlear nuclei pass sound info on to?

Answer 16

the superior olivary nuclei in the pons on both sides

Question 17

What is the role of the superior olivary nucleus?

Answer 17

1. compares intensity and delay of sound in each ear
2. differences in the nuclei allows sound location accurate to 1 degree of an arc

Question 18

What does the superior olivary nucleus pass sound info on to?

Answer 18

The inferior colliculi

Question 19

What are the imp connections of the inferior colliculi nuclei?

Answer 19

1. nuclei controlling head and neck movement
2. spinal cord controlling muscles of neck
3. spinal cord controlling postural muscles

Question 20

What is the job of the inferior colliculi nuclei?

Answer 20

Provides connections which enable the following of moving sound sources with eyes, head, and alteration of body posture

Question 21

What does the inferior colliculi pass sound info on to?

Answer 21

the thalamus through the medial geniculate nuclei

Question 22

What is the role of the thalamus with auditory info?

Answer 22

Sends incoming info to the whole cortex aswell as primary auditory complex to alert the brain to incoming info

Question 23

What does the thalamus pass the auditory info on to?

Answer 23

the primary auditory cortex in the transverse temporal gyri

Question 24

What is the pathway of sound info?

Answer 24

1. outer ear
2. middle ear
3. inner ear
4. vestibulocochlear nerve
5. cochlear nuclei
6. superior olivary nucleus
7. inferior colliculi nuclei
8. thalamus
9. auditory cortex

Question 25

What is different about the auditory pathways when compared with other pathways?

Answer 25

1. cross paths repeatedly
2. several nuclei along the pathway where synapses occur
   3, each synaptic relay plays a different role in auditory function
3. contralateral pathways