Ear

Hearing : cochlea (organ of corti) Balance: Semicircular canals (3D) and utricle/saccule (head balance)

• Outer ear (Pinna, auditory canal) • Middle ear (tympanic membrane, ossicles, eustachian tube) • Inner ear (choclea/organ of corti, semicircular canals, auditory nerve)

• outer ear flap • collect/focus sound waves

• carry sound wave to tympanic memmbrane • ear wax comes from sweat glands here

• eardrum • pass sound wave vibration to ossicles

• consists of 3 small bones Amplify/pass sound vibrations through the: Mallus/hammer: Incus (anvil): Stirrup (stapes)

equalizes air pressure btwn middle ear and outside environment - why your ears pop on plane

• snail shell • filled with fluid • the specalized hair cells vibrate when the fluid moves • convert sound to nerve impulse

• fluid filled 3 canals contains hair that bend in response • gives sensory information to brain for balance/equilbrium • not sound!

transmits sensory info to brain

oval window: small above round window: base of snail shell

• chamber found at the base of semicircular canals provides info about static equilbrium • connected to middle ear by 2 small savs (utricle and saccule) that establish head position

anchors the receptor hair cells in the organ of corti

vestibule: head balance semi circular canals: body balance

• Pinna collects sound waves to the audacity canal • Auditory canal to eardrum • Ear drum vibrates and ossicles starts vibrating • Ossicles increase pressure of sound waves for the inner ear. The inner ear has liquid in it. (Needs lots of pressure) • Inner ear..The cochlea (snail) has liquid inside it. When ossicles hit cochlea the cochlea vibrates. Cells inside cochlea turns vibrations into electrical signals. • When inside the cochlea it vibrates the basilar membrane (base of cochlea/prgan of court) which bends the hair cells. The bending causes depolarization of sensory neutron which sends signal to auditory nerve.