The ear Flashcards
What makes up the outer ear?
Outer ear: includes the auricle, external auditory meatus, and the tympanic membrane.
What is the auricle?
Auricle: the AUDITORY CANAL. It is made of elastic cartilage and keratinized stratified squamous epithelium. It also has hair follicles.
What is the external auditory meatus?
External auditory meatus: the outer third is made of elastic cartilage and the inner two thirds is bone. It is lined with stratified squamous epithelium and has glands that produce sweat and earwax.
What is the tympanic membrane?
Tympanic membrane: EARDRUM. Separates the external auditory canal from the middle ear. It has vascularized connective tissue, which covered by a layer of skin. The internal surface is covered by simple cuboidal epithelium.
What are the three regions of the middle ear?
The middle ear contains auditory ossicles, openings and muscles.
That is the malleus?
Malleus: attaches to the tympanic membrane and hits the anvil.
What is the incus (anvil)?
Incus: intermediate bone between the malleus and stapes.
What is the stapes?
Stapes: is shaped like a stirrup and inserts into the oval window. When the stapes vibrates, the oval window also vibrates.
What are the two openings found in the middle ear?
Openings – the oval window and round window
What is the oval window?
Oval window: the stapes attaches to the membrane of the oval window, which opens into the scala vestibuli.
What is the round window?
Round window: at the end of the scala tympani.
What are the two muscles found in the middle ear?
Muscles – tensor tympani and stapedius.
What is the tensor tympani?
Tensor tympani: inserts on the malleus.
What is the stapedius?
Stapedius: inserts on the stapes.
What are the functions of the tensor tympani and stapedius?
These muscles contract reflexively in response to loud sounds in order to damped the vibrations of the auditory ossicles. They are usually too late, but are useful in helping to ignore the sounds of one’s voice.
What are the components of the inner ear?
Inner Ear – bony labyrinth, membranous labyrinth, vestibular organ and auditory organ.
What is the bony labyrinth?
Bony labyrinth: canals and chambers in the petrous portion of the temporal bone. It contains sodium-rich lymph. It has four regions – semicircular canals, cochlea, scala vestibuli and scala tympani.
What is the membranus labyrinth?
Membranous labyrinth: has potassium rich lymph. It also has structures embedded within the bony labrinth.
What are the vestibular organs?
Vestibular organs: sensory structures that sense a chang ein position. They include saccule and utricle, as well as cristae.
What are the maculae of the accule and utrile?
Maculae of accule and utrile: composed columnar cells and hair cells. The hair cells are in contact with nerve endings, and the otolithic membrane is a gelatinous memberane that overlies the epithelium. It has hair cells and causes sensory impulses via movements of the head and otolithic membrane.
What are the cristae aumpullaris of the inner ear?
Cristae ampullaris of semicircular ducts: has columnar supporting cells and hair cells.
What is the cupula?
Cupula: a gelatinous layer similar to the otolithic membarne, but there are no ostoliths. Movement causes forces between the semicircular canals and the contained fluid. Moving fluid displaces the cupula and causes the stereocilia to bend.
What does the cochlear duct divide?
The cochlear duct divides the bony cochlea into scala vestibuli and tympani. The
What form the roof and floor of the cochlear duct?
vestibular membrane forms the roofof the duct and the basilar membrane forms the floor of the duct.
