anatomy and histology of the ear Flashcards
what are the symptoms associated with menieres disease?
an inner ear disorder with symptoms that include vertigo, tinnitus, hearing loss and the sensation of ear fullness.)
what structures form the external ear
auricle, tympanic membrane, and external acoustic meatus
what is the blood supply of the auricle?
posterior auricular and superficial temporal vessels
what is the innervation of the auricle?
greater auricular nerve (cervical plexus) and auriculotemporal nerve (V3)
what composes the auricle?
concha- deep depression found in auricle
helix (outer rim)
antihelix (inner rim)
tragus (protrusion overlapping external acoustic meatus) and antitragus
lobule (contains non cartilagenous CT) everything else is elastic CT
what kind of glands are found within the external acoustic meatus?
ceraminous (wax) and sebaceous glands are found within the integument with cartilage found beneath to support the outer portion of the canal
what type of epithelia composes the outside layer of the tympanic membrane?
stratified squamous epithelium
what epithelia lines the inside layer of the tympanic membrane?
simple cuboidal epithelium
what is the tip of the tympanic membrane called and where is it pointed to
umbo; pointed towards the external acoustic meatus
where does the tympanic membrane transmit its movement (sound)?
transmits movement by sound to the ossicles
what is the innervation of the tympanic membrane?
A) external surface by auriculotemporal nerve
B) inner surface by small branch of CN V3 and by small auricular branch of vagus nerve
what antibiotic should you avoid when treating a perforated tympanic membrane?
gentamycin
what structures are found within the middle ear (tympanic cavity)?
within the tympanic cavity lies the auditory ossicles: stapes, incus, and malleus; round and oval window; pharyngotympanic tube (eustachian tube)
what is the location for the external ear?
dense petrous portion of the temporal bone
what is the location for the middle ear?
petrous portion of temporal bone
what are the two parts of the middle ear?
tympanic cavity proper and epitympanic recess
what are the walls of the middle ear?
tegmental wall (epitympanic recess- roof); jugular wall (floor); membranous wall (lateral); labyrinthine wall (medial); mastoid wall (posterior); carotid wall (anterior)- near opening of pharyngotympanic tube and canal for tensor tympani
describe the eustachian tube (pharyngotympanic tube)
connects tympanic cavity with nasopharynx- functions to equalize pressures; posterolateral part is bone, rest is elastic cartilage
what structures is the eustachian tube open to?
levator veli palatine, tensor veli palatine and salpingopharyngeus muscles
what is the course for auditory ausicles?
from tympanic membrane to oval window of cochlea
what does the base/ footplate of the stapes (stirrup) attach to?
the oval window
what muscles are associated with the ossicles within the middle ear?
tensor tympani muscle (V), stapedius muscle (VII),
what is the function of the tensor tympani muscle within the middle ear?
inserts on handle of malleolus and pulls on handle to tense tympanic membrane and reduce amplitude.
what is the function of the stapedius muscle within the middle ear?
inserts on the stapes and pulls the stapes posteriorly tightening annular ligament attaching it to window oval window; reduces oscillatory range and prevents excessive movement of the stapes