Ear Flashcards
the auricle of the ear receives its blood supply by what?
the posterior auricular and superficial temporal vessels
sensory innervation of the auricle is via what?
the great auricular nerve (cervical plexus) and the auriculotemporal nerve (V3)
what glands are located in the external acoustic meatus?
ceruminous glands (make wax) and sebaceous glands
the outside layer of the tympanic membrane is lined with what?
stratified squamous epithelium
the inside layer of the tympanic membrane is lined with what?
simple cuboidal epithelium
the tip of the tympanic membrane is known as what?
umbo
the tympanic membrane transmits sound to what?
the ossicles of the ear
the external surface of the tympanic membrane is innervated by what?
auriculotemporal nerve (V3)
the inner surface of the tympanic membrane is innervated by what?
by a small branch of CN V3 and by a small auricular branch of the vagus nerve
what often causes a perforated tympanic membrane?
abnormal increase in the medial ear pressure or external trauma
where is the middle ear located?
in the petrous portion of the temporal bone
what are the two parts pf the middle ear?
tympanic cavity proper and the epitympanic recess
what is the purpose of the pharyngotympanic/ eustachian tube?
connects the tympanic cavity with the nasopharynx–> equalizes the pressure
what is the pharyngotympanic/eustachian tube opened by?
levator veli palatine, tensor veli palatine, and salpinopharyngeus muscles
what are the three auditory ossicles?
malleus, incus, and stapes
what does the stapes attach to besides the incus?
the oval window
what two muscles are associated with the auditory ossicles?
tensor tympani and stapedius muscle
What is the role of the tensor tympani muscle?
it protects from too large of a mechanical wave that is being transmitted to the ear
what is the role of the stapedius muscle?
it dampens the sound that is being transmitted to the inner ear
what is otitis media?
ear ache with possible fluid or pus in the middle ear
how can mastoiditis spread into the cranial fossa?
via the petrosquamous cranial suture
what are the three parts of the bony labyrinth?
semicircular canals, vestibule, and cochlea
what is contained within the vestibule of the bony labyrinth?
saccule and utricle
what lies within the bony labyrinth?
the membranous labyrinth
what are the two parts of the membranous labyrinth?
the vestibular division and the cochlear division
what is contained within the vestibular division of the membranous labyrinth and what is its purpose?
semicircular ducts, utricle, and saccule; balance and orientation
what is the purpose of the cochlear division of the membranous labyrinth?
sound
where are the sensory cells of the ear found?
3 cristae ampullaris, 2 maculae, and one organ of corti
what is the role of the mechanosensory cells?
they convert mechanical energy into electrical energy transmitted via CN VIII
where is the perilymphatic space located?
between the bony and membranous labyrinths
where is the endolympathic space located?
within the membranous labyrinth
what is the ion concentration of endolymph?
high in K+ but low in Na+
where does the endolymph drain into?
venous sinuses of dura mater via endolymphatic duct
where does perilymph drain into?
into subarachnoid space via perilymphatic duct
what is the name for the one true cilia?
kinocilium
where is the kinocilium located?
behind the tallest stereocilia
if deflected toward the tallest stereocilia, what happens to the K+ channels in the stereocilia?
they open
what is the cochlear duct divided into?
scala media, scala vestibuli, and scala tympani
what is contained within the kinocilium?
microtubules
which system has the kinocilium with microtubules?
vestibular system
which system does not have the cilia structure but only the basal body?
auditory system
How hair hair cells innervated?
both efferently and afferently
which part of the cochlear duct contains the endolymph?
the scala media
what is the lateral wall of the scala media known as?
stria vascularis
what is significant about the stria vascularis?
it is the source of endolymph
where is the organ of corti located?
on the floor of the scala media resting on the basilar membrane
how many rows of outer hair cells are there on the organ of corti?
3 rows
how many rows of inner hair cells are there on the organ of corti?
1 single row
which region is moved by the stapes at the oval window?
scala vestibuli
which region is connected to the round window?
scala tympani
where would high frequency sounds be detected at?
near the base of the cochlea
where would low frequency sounds be detected at?
closer to the tip of the duct
which part of the ear is damaged with conductive hearing loss?
outer or middle ear
which part of the ear is damaged with sensorineural hearing loss?
inner ear
which hearing loss is age-related or noise induced?
sensorineural hearing loss
What is the issue with central hearing loss?
a problem with the CNS
what do the ends of the semicircular canals have?
ampullas
What is the cap of the ampulla called?
cupula
what is the purpose of the cupula?
serves as a sensor for rotational velocity
what do the utricle and saccule contain?
each contain a macula
what does a macula consist of?
a cluster of hair cells with an overlying otolithic membrane and that membrane is covered with crystals called otoconia
what is the role of the otoconia found within a macula?
serve as sensors for gravity and linear acceleration
What is Meniere’s syndrome related to?
increase in endolymph volume leading to abnormal signaling
