the inner ear

what does the inner ear contain?

vestibulocochlear organs

what are the 2 main functions of the inner ear?

- convert mechanical signals from middle ear into electrical signals

- maintain balance by detecting position + motion

which part of the temporal bone does the inner ear lie within?

petrous part of temporal bone

what does the inner ear lie between?

middle ear and internal acoustic meatus

what are the 2 main components of the inner ear?

- bony labyrinth

- membranous labyrinth

what does the bony labyrinth consist of?

- cochlea

- vestibule

- 3 x semi-circular canals

what are the structures of the bony labyrinth lined with?

periosteum

what do the structures of the bony labyrinth contain?

fluid called perilymph

where is the vestibule located in the bony labyrinth?

central part - between cochlea and semi-circular canals

how is the vestibule separated from the middle ear?

by the oval window

which parts of the membranous labyrinth lie within the vestibule?

- saccule

- utricle

which part of the membranous labyrinth lie within the cochlea?

cochlea duct

what shape is the cochlea?

spiral/snail-shaped

what holds the cochlear duct in place in the cochlea?

spiral lamina

what is the chamber above the cochlear duct called?

scala vestibuli

what is the chamber below the cochlear duct called?

scala tympani

what is the opening of the cochlea called?

round window

what part of the membranous labyrinth is held in the semi-circular canals?

semi-circular ducts

what angles are the canals situated to each other?

90 degrees

what is the swelling at the end of each canal called?

the ampulla

where is the membranous labyrinth located?

within the bony labyrinth

what does the membranous labyrinth consist of?

- cochlear duct

- semi-circular ducts

- utricle

- saccule

what is contained in the membranous labyrinth components?

endolymph

what is the 'organ of hearing'?

cochlear duct

what are the 'organs of balance'/vestibular apparatus?

semicircular ducts, saccule + utricle

what shape is the cochlear duct?

triangular (cross-section)

what membrane lies on the roof of the cochlear duct?

Reissner's membrane

what membrane lies on the floor of the cochlear duct?

basilar membrane

what cells are found on the basilar membrane?

epithelial cells of hearing

what are the epithelial cells of hearing called?

the organ of corti

what are the saccule and urticle?

2 membranous sacs in the vestibule

which organ of balance detects movement of the head in the vertical plane?

saccule

which organ of balance detects movement of the head in the horizontal plane?

utricle

what structure does the saccule receive?

the cochlear duct

what structures does the utricle receive?

the three semicircular ducts

where does the endolymph drain from the saccule and utricle?

into the endolymphatic duct

where does the endolymphatic duct lead to?

into the endolymphatic sac

what arteries supply the bony labyrinth? (3)

branches from the:

- maxillary artery

- middle meningeal artery

- posterior auricular artery

which arteries supply the membranous labyrinth? (2)

labyrinthine artery from inferior cerebellar artery

what vein drains both membranous + bony labyrinth?

labyrinthine vein

which nerve innervates the inner ear?

vestibulocochlear nerve (CNVIII)