The Human Ear

Name the structures that make up the outer ear. Pinna External Auditory Meatus (Ear Canal) Tympanic Membrane (Ear Drum)

What are the ossicles? The small bones of the ear. Hammer (Malleus) Anvil (Incus) Stirrup (Stapes)

Name the structures that make up the bony (osseous) labyrinth. Cochlea Semicircular Canals Vestibule

Which structures are not involved in hearing Which structures are not involved in hearing? They contain the receptors for the sense of ↔. Semicircular Canals Vestibule

Which structure allows pressure in the middle ear to be equalized with Patm? Auditory Tube (Eustacian Tube)

This structure vibrates as longitudinal sound waves strike it; then transmits the vibrations to the ossicles. Tympanic Membrane (Ear Drum)

Connects the nasopharynx and middle ear Auditory (Eustacian) Tube

The structure that transmits vibrations from the stirrup to the fluid in the inner ear. Oval Window

The fluid that bathes the sensory receptors of the inner ear. Endolymph

The fluid contained within the osseous labyrinth that bathes the membranous labyrinth Perilymph

Contains the Organ of Corti Cochlea

Identify the major areas of the membranous labyrinth: semicircular canals, saccule, utricle, and cochlear duct

ID each receptor: Organ of Corti, Crista Ampullaris, Macula

Organ of Corti

Acoustic Macula Otoliths Gelatinous Cap Hair Cells Supporting Cells Vestibular Nerve Axons

Normal Hair Cells

Damaged Hair Cells

The receptors for ____ ↔ are found in the crista ampullaris of the ____. These receptors respond to Δs in ____ motion. When motion begins, the ___ fluid lags behind and the ___ is bent, which excites the hair cells. When motion stops suddenly, the fluid flows in the opposite dxn and again stimulates the hair cells

The receptors for ___ ↔ are found in the maculae of the ___ and ___. These receptors report the position of the head in space. Tiny stones found in a gel overlying the hair cells roll in response to the pull of ___.

As they roll, the gel moves and tugs on the hair cells, exciting them. Besides the ↔ receptors of the inner ear, the sense of ___ and ___ are also important in helping to maintain ↔.

Deafness

Conduction Can result from the fusion of the ossicles

Sensorineural Can result from damage to the cochlear nerve

Sensorineural Sound is heard in one ear but not in the other, during both bone and air conduction

Conduction Often improved by a hearing aid

Conduction and Sensorineural Can result from otitis media an inflammation/infection of the middle ear (the cavity between the eardrum and the inner ear).

Conduction Can result from XSive earwax or a perforated eardrum

Sensorineural Can result from a blood clot in the auditory cortex of the brain

Conduction Deafness hearing loss due to problems with the bones of the middle ear

Sensorineural (Central) Deafness Hearing loss or impairment due to a lesion or defect of the cochlea or the acoustic nerve.