Hearing Science Test 2 Definitions
Terms
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- The nerve that conveys neuroligical information from the inner ear structures to the central nervous system. it is also commonly referred to as the VIII cranial nerve. It is one portion of the sensorineural mechanism.
- Auditory nerve (VIII cranial nerve)
- The various neurological pathways that exist from the brainstem to the auditory areas in the cerebral cortex.
- Central auditory mechanism
- occurs when there is some abnormality in the central auditory mechanism; that is, when an abnormal condition exists anywhere from the level of the brainstem to the auditory cortex
- central hearing loss
- the spiral-shaped portion of the inner ear that contains the sensory organ of hearing; one portion of the sensorineural mechanism
- cochlea
- occurs when there is some abnormality in the conductive mechanism; that is, when an abnormal condition exists in the outer or middle ears
- conductive hearing loss
- its purpose is to collect sound energy and then to change (transduce) this airborne energy into mechanical vibration so that it can be processed by the sensorineural mechanism. It is made up of the outer and middle ear.
- conductive mechanism
- the open channel from the concha to the tympanic membrane; purpose is to direct acoustic energy to the middle ear; aka the ear canal
- external auditory meatus
- the innermost portion of the ear which consists of the cochlea, the vestibular mechanism, and the auditory nerve (VIII cranial nerve); purpose is to convert vibrational energy from the middle ear to neurological impulses which are sent to the central aud
- inner ear
- an air-filled space located in the temporal bone, which contains three small bones (the ossicles) and the eardrum; purpose is to transfer sound energy from the outer ear to the inner ear
- middle ear
- the outermost portion of the ear, which consists of the pinna and the exteranl auditory meatus (ear canal); purpose is to collect sound energy and deliver it to the middle ear
- outer ear
- the visible portion of the outer ear; composed of cartilage and characterized by a number of depressions; aka the auricle
- pinna
- occurs when there is some abnormality in the sensorineural mechanism; that is, when an abnormal condition exists in the cochlea or VIII nerve
- sensorineural hearing loss
- a ring of elastic fibers that encircles the stapes footplate, holding the stapes in the oval window
- annular ligament
- a wax-like secretion produced by specialized glands in the external auditory meatus; commonly referred to as ear wax
- cerumen
- a branch of the facial (VII cranial) nerve that passes through the middle ear; carries information about taste from the front portion of the tongue to the central nervous system
- chorda tympani
- the hollowed-out portion of the pinna that adjoins the external ear canal
- concha
- a channel that joins the tympanic cavity to the nasopharynx; purpose is to equalize the air pressure in the tympanic cavity to the outside pressure, to allow air into the middle ear, and to remove secretions from the tympanic cavity
- Eustachian tube (auditory tube)
- the middlemost bone in the ossicular chain; joins the malleus to the stapes
- incus
- one of the three middle ear ossicles; most lateral of the ossicles, and is partially embedded in the tympanic membrane
- malleus
- the long arm or process of the malleus which is embedded in the fibrous layer of the tympanic membrane
- manubrium
- is formed by the gap in the tympanic sulcus; is occupied by the highest portion of hte eardrum (pars flaccida)
- notch of Rivinus (tympanic notch)
- an instrument consisting of a light source and a magnifying lens, which is designed to observe the ear canal and the tympanic membrane
- otoscope
- the small triangular-shaped portion of the upper eardrum; this area of the eardrum is quite thin and flaccid
- pars flaccida (Shrapnell's membrane)
- the entire eardrum except for the small triangular-shaped area
- pars tensa
- a small, bony projection from the posterior wall of the tympanic cavity from which the tendon of the stapedius muscle emerges
- pyramidal eminence
- one of the two tiny muscles of the middle ear; arises form the posterior wall of the middle ear and its tendon is attached to the stapes; innervated by the VII cranial (facial) nerve
- stapedius muscle
- the smallest and innermost bone in the ossicular chain; attached on one side to the incus and on the other side fits into the oval window
- stapes
- one of the two tiny muscles found in the middle ear; arises from the anterior wall and its tendon is attached to the malleus; innervated by the V (trigeminal) nerve
- tensor tympani muscle
- the cavity of the middle ear; is roughly cube shaped and lined with mucous membrane; contains the ossicular chain, the middle ear muscles, and the oval and round windows, among other structures; communicates with the nasopharynx through the Eustachian tu
- tympanic cavity (aka middle ear)
- the groove in the bony portion of the external auditory meatus in which the tympanic membrane is attached
- tympanic sulcus
- in medicine, associated with the closure of a normal opening; in the ear, associated with a closed external auditory meatus
- atresia
- a cyst which typically grows from the upper portion of the tympanic membrane. a pouch is formed, into which the dead skin that lines the pouch sheds. As more skin is shed into the pouch, it grows. The effect is that of a foreign object within the middle
- cholesteatoma
- occurs when infection persists in the middle ear cavity for a prolonged time period; ear will often discharge pus, which has a foul odor
- chronic otitis media
- refers to one aspect of the transformer action of the middle ear. Sound is collected over a relatively large area (the eardrum) and is transferred to an area 13 times smaller--the stapes footplate. This, in effect, causes a pressure increase at the oval
- condensation effect
- occurs when changes in the skin that lines the exteranl auditory meatus permit the growth of bacteria of fungi. When this occurs, there is considerable swelling of the canal walls. Hearing loss occurs only when the ear canal is completely closed.
- external otitis ("swimmer's ear")
- A common cause of conductive hearing loss due to the blocking of the ear canal with cerumen
- impacted cerumen
- the mechanical advantage that is gained through the combined effect of the malleus and the incus. This accounts for about 2 dB of the total 25 dB of amplification provided by the middle ear system
- lever action
- a surgical operation that aims to remove diseased mastoid air cells. There are several forms, each with a different purpose.
- mastoidectomy
- an inflammation of the mastoid air cells
- mastoiditis
- occurs when the fluid present within the tympanic cavity is thickened. The thickened fluid is not infected
- mucous otitis media
- an operation designed to repair a perforation of the tympanic membrane
- myringoplasty
- a surgical incision of the eardrum to drain fluid or pus
- myringotomy
- those conditions in which fluid present within the middle ear cavity is noninfected. Both serous otitis media and mucous otitis media fall into this category
- nonsuppurative otitis media
- occurs whenever the ossicular chain is interrupted. The cause may be head trauma, fracture, or disease
- ossicular discontinuity
- a condition in which conductive hearing loss occurs, usually through a gradual fixation of the stapes in the oval window. Although the actual cause is unknown, a pathological condition occurs such that new bony growth is laid down around the stapes footp
- otosclerosis
- a common cause of conductive loss. It may arise as the result of a head cold, allergies, enlarged adenoids, or other conditions that impair Eustachian tube function. The condition is characterized by the accumulation of clear, thin fluid within the middl
- serous otitis media
- a surgical procedure to improve hearing in cases of otosclerosis. In this operation, the immobile stapes is first removed and is then replaced by a prosthesis.
- stapedectomy
- A condition in which fluid is present in the middle ear and the fluid has become infected (pus formation). This condition is also known as purulent otitis media.
- suppurative otitis media
- the biological amplification process in the middle ear that allows the efficient transfer of energy from the low impedance middle ear to the high impedance perilymph. It is made up of the condensation effect and the lever action.
- transformer action
- a surgical procedure that aims to reconstruct the middle ear's conductive function; one form involves grafting various types of tissue to replace or repair a diseased or perforated eardrum.
- tympanoplasty