Ear Flashcards
External auditory canal
Directs sound to tympanic membrane (eardrum)
Ossicles
- stapes
- incus
- malleus
(In middle ear) 3 smallest bones in body and help transmit and amplify vibrations from tympanic membrane to inner ear
Eustachian tube
Connects middle ear to nasal cavity and helps equalize pressure between middle ear and environment
Vestibule
Contains utricle and saccule which are sensitive to linear acceleration (which is used as part of balancing and determining orientation) right outside of cochlea. Both contain hair cells covered with otoliths which resist motion
Semicircular canals
Sensitive to rotational acceleration, each end in ampulla. Endolymph in semicircular canals resist motion
Endolymph
In membranous labyrinth. Potassium-rich fluid inside of perilymph.
Perilymph
In bony labyrinth. Transmits vibrations from outside world and and cushions inner ear structures
Cochlea
Divided into 3 parts called scalae
- middle scala houses organ of corti
- other two filled with perilymph and surround hearing apparatus
Organ of Corti
Actual hearing apparatus. Contains hair cells bathes in Endolymph. Rests on Basilar membrane. On top of it is tectorial membrane.
Round window
Allows perilymph to move into cochlea
Hair cells
Convert physical stimuli into electrical signals
Auditory (vestibulocochlear) nerve
Takes signal to CNS
Auditory cortex
Sound processing
Superior olive
Localizes sound (above)
Inferior colliculus
Involved in startle reflex and helps keep eyes fixed on point when head is turned
