Anatomy of Ear Flashcards
3 areas of ear
- external ear
- middle ear
- inner ear
external ear
from auricle to tympanic membrane
middle ear
air filled chamber containing the ossicle bones
inner ear
bony and membranous labyrinths filled with fluid, contains sense organs for balance and hearing
auricle
- part of ear seen externally
- shaped to funnel sound waves into external acoustic meatus
rim
cartilaginous part of outer ear
lobule
ear lobe (part of auricle that lacks cartilage)
cerumen
ear wax, secreted by glands within acoustic canal
external acoustic canal
- 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
tympanic membrane
“ear drum”
- thin membrane of connective tissue that vibrates to transmit sound energy to middle ear
- marks end of external ear
malleus
- hammer bone
- receives vibrations from ear drum, transfers them to incus
ossicles
- smallest bones in body
- 3 in each ear: malleus, incus, stapes
incus
- anvil bone
- transfers vibrations to stapes
stapes
conveys vibrations to inner ear
vestibule
- first section of inner ear, connects to 3 semicircular canals
semicircular canals
- provide body’s vestibular system
equilibrium receptors
- 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
CN VII’s role in hearing
innervates the stapedius muscle attached to stapes –> controls amount of tension in bone –> controls amount of vibration –> controls intensity of sound
cochlea
- spiral, bony chamber in inner ear
- contains membranous endolymph filled cochlear duct
- houses organ of corti
- terminates at cochlear nerve (of CN VIII)
cochlear nerve
branch of CN VIII
innervates cochlea
organ of corti
- sense organ of auditory system
- contains tectorial membrane and stereocilia
tectorial membrane
receives vibrations from fluid within cochlear ducts –> moves and bends stereocilia
stereocilia
- tiny hairs within organ of corti
- when move, cause action potential in neurons of CN VIII
