(neuro) auditory system

Question 1

how many sections is the ear divided into?

Answer 1

outer, middle, and inner ear

Question 2

where is the ear embedded?

Answer 2

petrous part of the temporal bone

Question 3

why is it important that the ear is embedded in the temporal bone?

Answer 3

temporal bone = hardest bone in the body

so can protect the delicate structure of the ear well

Question 4

what are the functions of the outer ear?

Answer 4

to capture sound and to focus it onto the tympanic membrane

to amplify some frequencies by resonance in the canal

to protect the ear from extrenal threats

Question 5

what is the tympanic membrane also known as?

Answer 5

eardrum

Question 6

how is the ear adapted for protection from external threats?

Answer 6

have cilia in the external acoustic meatus that waft to extrude unwanted elements from entering the ear

have ear wax that will trap the unwanted external elements + has a pH that is toxic for pathogenic material

Question 7

what is the main function of the middle ear?

Answer 7

amplification

Question 8

how is sound amplified in the middle ear?

Answer 8

vibrations are focussed from the tympanic membrane (larger SA) onto the oval window (smaller SA)

the change in surface area causes in increase in pressure

Question 9

what impact does the focussing of vibrations have?

Answer 9

the decrease in SA from the large tympanic membrane to the smaller oval window causes an increase in pressure

Question 10

how is the force increased on the oval window?

Answer 10

using leverage from the incus-stapes joint

Question 11

what does the middle ear consist of?

Answer 11

tympanic membrane

ossicles (malleus, incus, stapes)

stapedius muscle

oval window

Question 12

what are the ossicles?

Answer 12

smallest bones in the body

include the malleus, incus and stapes

Question 13

name the three ossicles

Answer 13

malleus, incus, stapes

Question 14

describe the structure of the ossicles

Answer 14

the malleus is attached to the inner surface of the eardrum

the malleus articulates with the incus which in turn articulates with the stapes

Question 15

what is the oval window?

Answer 15

membrane-covered opening from the base of the stapes in the middle ear to the cochlea of the inner ear

Question 16

describe the path of sound amplification in middle ear

Answer 16

vibration hit the tympanic membrane

transmit vibrations to the chain of connected ossicles

vibrations focussed onto the connective tissue membrane called the oval window

the focussing of the vibrations causes an increase in pressure = amplification of sound

sound is transmitted into the inner ear

Question 17

what is the oval window?

Answer 17

connective tissue membrane located at the end of the middle ear at the base of the stapes and the beginning of the inner ear

responsible for stimulating the movement of auditory fluids in the cochlea and the activation of receptors for hearing

Question 18

what is the hearing part of the inner ear?

Answer 18

cochlea

Question 19

what is the function of the cochlea?

Answer 19

transduces vibrations into nervous impulses

produces a frequency (pitch) and amplitude (loudness) analysis of the sound

Question 20

what does the frequency and amplitude of the sound determine?

Answer 20

will determine the location of the ear in which the cells will be stimulated

i.e. different frequencies and amplitudes will stimulate cells in different parts of the ear

Question 21

what is the alternative function of the cochlea besides transduction?

Answer 21

produce a frequency (pitch) and amplitude (loudness) analysis of the sound

Question 22

describe the structure of the cochlea

Answer 22

hollow, spiral-shaped bone found in the inner ear

cochlear duct is divided into thee compartments: scala vestibuli, scala media and scala tympani

Question 23

name the three compartments of the cochlear duct

Answer 23

scala vestibuli, scala media and scala tympani

Question 24

what structure separates the cochlea into its three compartments?

Answer 24

oval window

Question 25

describe the structure of the scala vestibuli and the scala tympani

Answer 25

both scalae are bony structures that are filled with perilymph (w the membranous scala media in between them) communicate w each other via the helicotrema (an opening at the apex of the cochlea)

Question 26

what do the scala vestibuli and scala tympani contain?

Answer 26

perilymph (high in sodium)

Question 27

what is the perilymph and why is it important?

Answer 27

sodium-rich fluid found in the bony labyrinth of the scala vestibuli and the scala tympani, surround the endolymph in the membranous labyrinth of the scala media resembles extracellular fluid and transmits sound waves to the endolymph

Question 28

which membranes are linked to the scala vestibuli and the scala tympani?

Answer 28

scala vestibuli = vestibular membrane scala tympani = basilar membrane

Question 29

how do the scala tympani and the scala vestibuli communicate?

Answer 29

communicate w each other via the helicotrema (an opening at the apex of the cochlea)

Question 30

what is the cochlea?

Answer 30

hollow, spiral-shaped bone found in the inner ear transforms the vibrations of the auditory fluids into neural signals for interpretation by the brain

Question 31

what is the function of the cochlea?

Answer 31

transforms the vibrations of the auditory fluids into neural signals for interpretation by the brain

Question 32

which mineral ion is the perilymph high in?

Answer 32

sodium

Question 33

what structure sits in between the scala vestibule and the scala vestibuli?

Answer 33

scala media

Question 34

what is the scala media?

Answer 34

membranous structure that contains endolymph, rich in potassium

Question 35

what does the scala media contain?

Answer 35

endolymph, rich in potassium

Question 36

which mineral ion is the endolymph high in?

Answer 36

potassium

Question 37

compare the perilymph with the endolymph

Answer 37

perilymph = found in the bony labyrinth of the scala vestibuli and scala tympani, rich in sodium and mimics extracellular fluid, transmits vibrations to the endolymph endolymph = found in the membranous labyrinth of the scala media, Irish in potassium and mimics intracellular fluid, transmits vibrations to the hair cells

Question 38

which structure is linked to the scala media?

Answer 38

organ of Corti

Question 39

where is the perilymph located?

Answer 39

in the bony labyrinth of the scala vestibuli and scala tympani

Question 40

where is the endolymph located?

Answer 40

in the membranous labyrinth of the scala media

Question 41

where is the organ of Corti found?

Answer 41

within the scala media

Question 42

what is the helicotrema?

Answer 42

an opening at the apex of the cochlea which is the point of communication between the scala vestibuli and the scala tympani

Question 43

where is the organ of Corti found?

Answer 43

within the basilar membrane (between the scala media and the scala tympani)