Study Guide for the Ear

describe the functions of the ear
Outer ear gathers sound, Middle ear amplifies and transmits air waves to inner ear, Inner ear transduces sound waves into action potential

Identify the three parts of the ear and the function of each part
The External Ear- called the auricle or pinna, funnels sound waves into the ears opening called the external auditory canal.

The Middle Ear- Transmits sound vibrations across the tiny bony ossicle chain to the inner ear. Protects the inner ear by reducing amplitude of loud sounds, equalizes the air pressure on both sides of the tympanic membrane to prevent it from rupturing.

The Inner Ear- structures and liquids that relay sound waves to the auditory nerve fibers on a path to the brain for interpretation of sound

External auditory canal
External auditory canal
either of the passages in the outer ear from the auricle to the tympanic membrane

pinna
outer ear

tympanic membrane
tympanic membrane
The eardrum. A structure that separates the outer ear from the middle ear and vibrates in response to sound waves.

malleus
the ossicle attached to the eardrum, or the hammer

incus
anvil; middle of the three auditory ossicles of the middle ear

stapes
one of the three bones of the middle ear shaped like stirrups

round window
one of the two openings into the cochlea of the inner ear; closed off from the middle ear by the round window membrane, which vibrates with opposite phase to vibrations entering the cochlea through the oval window; allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur

Eustachian tube
A narrow tube between the middle ear and the throat that serves to equalize pressure on both sides of the eardrum

cochlea
the snail-shaped tube (in the inner ear coiled around the modiolus) where sound vibrations are converted into nerve impulses by the Organ of Corti

vestibule
middle part of the inner ear in front of the semicircular canals and behind the cochlea that contains the utricle and saccule

cerumen
a soft honey colored wax secreted by glands in the ear canal

tympanic membrane
It is tilted toward the ear canal, facing downward and somewhat forward round in shape.

tympanic membrane- cone of light, umbo, and the annulus.

otitis media in the child
Eustachian tube is more horizontal therefore otitied media can form from bacteria that the cold has, therefore it is more able to get stuck in the tube and cause otitis media

middle ear
the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window

semicircular canal
one of three structures within the inner ear that help monitor the position of the body

cochlea
a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

organ of corti
organ located in the cochlea; contains receptors (hair cells) that receive vibrations and generate nerve impulses for hearing

hearing process
bones in middle ear trasmit vibrations to cochlea=>pressure waves in the cochlea=>cause another membrane to vibrate binding its hair cells=>bending depolarizes the membranes of special receptors and sends action-potentials to the brain via the cranial nerve # 8.

conductive hearing loss
hearing impairment caused by interference with sound or vibratory energy in the external canal, middle ear, or ossicles

sensorineural hearing loss
hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerves; also called nerve deafness

otalgia
an ache localized in the middle or inner ear

tinnitus
a ringing or booming sensation in one or both ears

vertigo
the sensation of dizziness

maintaining equilibrium
the semicircular canals of the inner ear contain cristae– hair like structures that respond to body movements; when a person moves the cristae bend, releasing impulses through the vestibular portion of the acoustic nerve to the brain which controls balance.