Biology 14 Human ears Cheat Sheet by kkkklui

3 regions

outer

inner

Sound waves

collected by pinna are directed to eardrum

Earbones

amplify and transmit vibration to oval window

cause perilymph in cochlea to vibrate

Sensory hair cells (central canal)

stimulated

produce sensation of hearing

nerve impulses travel along auditory nerves to auditory centre in brain

Round window

releases fluid pressure in the cochlea to the air in middle ear

Pinna (ear flap)

flap of cartilage covered by skin

directs them along auditory canal to eardrum

wax

lubricates canal

Eardrum

thin, elastic membrane at the end of auditory canal

Ear bones

3 tiny ear bones

amplify and transmits vibration from eardrum to oval window

transmits vibration from ear bones to inner ear

Eustachian tube

tube connecting middle ear to pharynx

swallowing to open it to allow air to enter or leave middle ear

Unequal pressure

eardrum will bulge

cannot hear clearly

Cochlea

for hearing

perilymph

fluid in upper and lower canal

sensory hair cells

in central canal

endolymph vibrates

sensory hair cell hairs are bent

nerve impulses travels along auditory nerves to auditory centre in brain

sensory hair cells

detection of head movements

brain coordinate muscled to maintain body balance