Ear

Question 1

describe the development of the inner ear

Answer 1

develops 1st
ectoderm thickens to otic placodes which roll inwards to form otic pit, pinch off and forms otic vesicle.
these form membranous labyrinth

Question 2

describe the development of the middle ear

Answer 2

forms from outgrowth of 1st pharyngeal throat (endoderm of embryo neck)

Question 3

what are the regions of the membranous labyrinth

Answer 3

vestibular - for rotation and acceleration
cochlear - hearing

Question 4

how does the tympanic membrane (eardrum) form

Answer 4

touching of endoderm pouch and ectoderm groove

Question 5

what do ear bones form from

Answer 5

neural crest cells

Question 6

what are the elements in the outer ear

Answer 6

Pinna
Ear Canal
Ear Drum

Question 7

what is the function of the pinna

Answer 7

collects sound to transfer to middle ear

Question 8

how is the pinna innervated

Answer 8

facial nerve

Question 9

how does the pinna move and why

Answer 9

auricular muscles
for sound location and communication

Question 10

how is the pinna involved in thermoregulation

Answer 10

heat radiated off

Question 11

what produce cerumen (ear wax)

Answer 11

sebaceous and ceruminous glands

Question 12

whar are ceruminous glands

Answer 12

highly modified apocrine sweat glands

Question 13

which ossicle is attached to the tympanic membrane

Answer 13

malleus

Question 14

how are soundwaves sent to the middle ear

Answer 14

cause vibrations of the membrane - move through ossicles

Question 15

where is the middle ear found in the cranium

Answer 15

temporal bone (in temporal bulla)

Question 16

what is the function of the auditory tube

Answer 16

allow middle ear to communicate with pharynx
for pressure equalisation and gland secretions

Question 17

what is the function of the guttural pouch (in equids)

Answer 17

blood cooling due to high vascularisation (ex: carotid artery)

Question 18

name the 3 ossicles (ear bones)

Answer 18

malleus
incus
stapes

Question 19

what are the functions of the ossicles

Answer 19

transmit and amplify or decrease vibrations

Question 20

what is the cavity within the temporal bone

Answer 20

osseous labyrinth

Question 21

name the regions of the cochlea

Answer 21

inner cochlear duct
middle scala vestibuli
outer scala tympani

Question 22

how do vibrations move throughout the cochlear for hearing

Answer 22

cochlear duct vibrates which vibrate hair cells
these generate neural impulse which gets carried through cochlear nerve

Question 23

what are the function of semicurcular canals

Answer 23

detect rotations
(pitch, roll, yaw)

Question 24

how is rotation detected

Answer 24

movement of endolymph throughout semicircular canals

Question 25

how is acceleration detected

Answer 25

in the saccule and utricle (expansions of the membranous labyrinth)
hair cells bend

Question 26

how are signals from the membranous labyrinth sent to the brain

Answer 26

vestibulocochlear nerve