ear Flashcards
3 major sections of the ear
Outer or external ear.
Middle ear or tympanic cavity.
Inner ear or labyrinth.
Each section transmits sounds differently.
external ear
Conducts sound waves through air. Includes: Auricle (or pinna) . External auditory canal (or ear canal). Cerumen. Tympanic membrane (or eardrum).
auricle (pinna)
Collects waves traveling through air.
Channels sound waves to the external auditory canal.
external auditory canal
Slender tube lined with glands that produce a waxy secretion called cerumen.
cerumen
Sticky secretion that traps tiny foreign particles.
Prevents particles from entering deeper areas of the canal.
tympanic membrane
Flat, membranous structure drawn over the end of the ear canal.
Sound waves strike the TM, causing it to vibrate.
Movement of the TM causes movement of the three smallest bones of the body, collectively called the ossicles.
middle ear
Conducts sound waves through bone.
Includes:
Eustachian Tube
Ossicles: Three smallest bones of the body: Malleus ,Incus, Stapes
Located in the tympanic cavity.
Form a coupling between the TM and the cochlea.
These 3 bones articulate sound.
eustachian tube
Connects the middle ear to the pharynx.
Equalizes pressure on the outer and inner surfaces of the eardrum (TM).
When sudden pressure changes, pressure can be equalized on either side of the tympanic membrane by deliberate swallowing.
malleus
Aka: Hammer.
Attached to the TM.
Articulates with the incus.
incus
Aka: Anvil.
Located between the malleus and the stapes.
stapes
Aka: Stirrups.
Attached to the oval window of the cochlea.
Articulates with the incus.
inner ear
Conducts sound waves through fluid. Includes: Cochlea. Also includes the structures for equilibrium: Semicircular canals. Vestibule.
cochlea
Snail-shaped structure.
Filled with fluid called perilymph.
Inner surface lined with highly sensitive hearing structures called the organ of Corti.
Organ of Corti contain tiny nerve endings called hair cells.
Movement of the ossicles causes the stapes to exert a gentle pumping action against the oval window.
Pumping action forces the perilymph to disturb the hair cells.
Generates impulses that are transmitted to the brain via the auditory nerve.
Brain interprets impulses as sound.
equilibrium: inner ear (Labyrinth)
Located in the inner ear.
Consists of a system of fluid-filled tubes and sacs; as well as nerves that connect these structures to the brain.
equilibirum
Labyrinth located inside the bone of the skull.
Includes: Cochlea and the vestibular system (includes the vestibule and the semicircular canals).
equilibrium: vestibular system
Controls balance, posture, orientation, body response to movement and eye movement.
Contains: Semicircular canals and the vestibule.
Vestibule joins the cochlea and semicircular canals.