Anatomy of Ear

Question 1

3 areas of ear

Answer 1

1. external ear
2. middle ear
3. inner ear

Question 2

external ear

Answer 2

from auricle to tympanic membrane

Question 3

middle ear

Answer 3

air filled chamber containing the ossicle bones

Question 4

inner ear

Answer 4

bony and membranous labyrinths filled with fluid, contains sense organs for balance and hearing

Question 5

auricle

Answer 5

• part of ear seen externally

- shaped to funnel sound waves into external acoustic meatus

Question 6

rim

Answer 6

cartilaginous part of outer ear

Question 7

lobule

Answer 7

ear lobe (part of auricle that lacks cartilage)

Question 8

cerumen

Answer 8

ear wax, secreted by glands within acoustic canal

Question 9

external acoustic canal

Answer 9

• tunnel between auricle and tympanic membrane
• part of outer ear
• composed of elastic cartilage, becomes a cylinder through temporal bone
• lined with skin containing hairs and glands that secrete cerumen, which trap foreign debris to keep them from entering middle ear

Question 10

tympanic membrane

Answer 10

“ear drum”

• thin membrane of connective tissue that vibrates to transmit sound energy to middle ear
• marks end of external ear

Question 11

malleus

Answer 11

• hammer bone

- receives vibrations from ear drum, transfers them to incus

Question 12

ossicles

Answer 12

• smallest bones in body

- 3 in each ear: malleus, incus, stapes

Question 13

incus

Answer 13

• anvil bone

- transfers vibrations to stapes

Question 14

stapes

Answer 14

conveys vibrations to inner ear

Question 15

vestibule

Answer 15

• first section of inner ear, connects to 3 semicircular canals

Question 16

semicircular canals

Answer 16

• provide body’s vestibular system

Question 17

equilibrium receptors

Answer 17

• located in semicircular canals of inner ear
• cause action potentials in response to different types of head movement/rotation
• send those action potentials thru vestibular portion of CN VIII

Question 18

CN VII’s role in hearing

Answer 18

innervates the stapedius muscle attached to stapes –> controls amount of tension in bone –> controls amount of vibration –> controls intensity of sound

Question 19

cochlea

Answer 19

• spiral, bony chamber in inner ear
• contains membranous endolymph filled cochlear duct
• houses organ of corti
• terminates at cochlear nerve (of CN VIII)

Question 20

cochlear nerve

Answer 20

branch of CN VIII

innervates cochlea

Question 21

organ of corti

Answer 21

• sense organ of auditory system

- contains tectorial membrane and stereocilia

Question 22

tectorial membrane

Answer 22

receives vibrations from fluid within cochlear ducts –> moves and bends stereocilia

Question 23

stereocilia

Answer 23

• tiny hairs within organ of corti

- when move, cause action potential in neurons of CN VIII