auditory system

Question 1

external ear

Answer 1

collects sound waves and channels them inwards

• the auricle
• the external auditory canal
• the tympanic membrane

Question 2

middle ear

Answer 2

conveys signals to the oval windows

• the temporal bone
• the oval window
• the round window

Question 3

inner ear

Answer 3

contains the receptors for hearing and equilibrium

Question 4

the tympanic membrane

Answer 4

• eardrum

- separates the external canal and the middle ear

Question 5

ceruminous glands

Answer 5

• located near the exterior opening of the external canal

- help prevent dirt and foreign objects from entering the ear

Question 6

auditory ossicles

Answer 6

• the middle ear
• the malleus
• the incus
• the stapes

Question 7

Malleus

Answer 7

• “the handle” attaches to the internal surface of the tympanic membrane
• “the head” of the malleus forms a joint with the incus

Question 8

Incus

Answer 8

• incus joins with malleus joins into the oval window.

Question 9

tensor tympani and stapedius

Answer 9

• tiny skeletal muscles attached to the auditory ossicles
  TT = limits movement and increases the tension of the tympanic membrane to prevent damage from loud noises
  Stapedius = dampen large vibrations of the stapes due to loud noises and protects the oval window from damage

Question 10

eustachian tube

Answer 10

• connects the middle ear to the nasopharynx

Question 11

inner ear

Answer 11

• bony labyrinth - outer - fluid - perilymph

- membranous labyrinth - inner - fluid = endolymph

Question 12

Bony labyrinth

Answer 12

• semi-circular channels
• the vestibule
• the cochlea (the cochlea duct, the vestibular membrane and tympanic membrane).

Question 13

organ of corti

Answer 13

• rests on the basilar membrane
• ## has hair cells (receptors for hearing that extend onto the cochlea duct)

Question 14

tectorial membrane

Answer 14

• protects over and makes contact with the hair cells of the spiral organ

Question 15

auditory nerve stimulation

Answer 15

1. sound waves arrive at the tympanic membrane
2. movement of the tympanic membrane causes displacement of auditory ossicles
3. movement of the stapes at the oval window establishes pressure waves
4. the pressure waves distort the basilar membrane on their way to the round window of the tympanic duct.
5. Vibration of the basilar membrane causes vibration of the hair cells against the tectorial membrane.
6. Info. is sent to CNS

Question 16

frequencies in the basilar membrane

Answer 16

• changes wider/flexible at one end to narrow/shift at the other end.
• narrow = high frequencies
• wider cells = low frequencies = hair cells

Question 17

static equilibrium

Answer 17

refers to the maintenance of body position relative to the force of gravity

Question 18

dynamic equilibrium

Answer 18

• maintenance of body position in response to rotational movements

Question 19

receptor organ for dynamic

Answer 19

vestibular apparatus

Question 20

receptor for static

Answer 20

macula - a thickened region in utricle and saccule in vestibular apparatus

Question 21

hair cell

Answer 21

sensory receptors that detect changes in head position

Question 22

supporting cells

Answer 22

surround hair cells - provide structural and chemical support
- secrete gelatinous substance that forms the otolithic membrane

Question 23

Otoliths

Answer 23

• crystals of calcium carbonate on the otolithic membrane

- add weight to the membrane and increase the influence of gravity during movements

Question 24

how the head tilts backwards

Answer 24

• otolithic membrane slide down due to gravity
• bends the microvilli that farm hair bundles
• opens up ion channels, resulting in a depolarising graded potential in the hair cells
• cause the release of neurotransmitters

Question 25

semicircular duct

Answer 25

• arranged each loop lies at right angles at each other and allows it to detect rotational movement of head

Question 26

ampulla

Answer 26

• semicircular duct
• receptors of rotational movement
• includes the crista - hair cells

Question 27

copula

Answer 27

• membrane extends over the crista

- the microvilli that makeup hair bundles of hair cells project into the copula

Question 28

when you tilt your head side to side

Answer 28

• hair cells don’t move
• the endolymph in the semicircular duct moves = pushes on the cupula = bends the hair cells, opening ion channel and causing depolarisation and neuro transmitting.