Ear Flashcards
The external ear and middle ear
are mainly concerned with the transfer of sound to the internal ear, which
contains the organ for equilibrium as well as for hearing.
The tympanic
membrane separates the _____ from the _____.
_______ joins the middle ear to the nasopharynx.
external ear from middle ear.
pharyngotympanic
tube
The external ear consist of
Pinnia, external aucustic meatus, tympanicmembrane
The main nerves supplying the skin of the auricle are ___&____
the great auricular nerve and the auriculotemporal nerve.
The skin of the concha( the opening in the ear) is primarily innervated by _____.
Its a minor innervation
the auricular branch of the vagus nerve, with a minor contribution from the facial nerve
EAM
The lateral 1/3 is catelegenous
The medial two thirds of the meatus is bony and lined with thin
skin that is continuous with the external layer of the tympanic membrane
ceruminous and sebaceous glands in the subcutaneous tissue of the cartilaginous
part of the meatus produce cerumen EARWAX
The tympanic
membrane is covered with thin skin externally and mucous membrane of the
middle ear internally
the tympanic membrane has a slight curve towards the outer ear, and it has a small dip in the center called the umbo. The umbo is like the highest point of a cone, and the central axis of the tympanic membrane passes right through it,
The tympanicmembrane consist of
Par Flaccida: This is the thin, flaccid part of the membrane that is located superior (upper) to the lateral process of the malleus. It lacks the radial and circular fibers present in the rest of the membrane. It forms the lateral wall of the superior recess of the tympanic cavity.
Pars Tensa: This is the thicker part of the membrane that is found in the remainder of the membrane. It contains radial and circular fibers, which provide structural support and contribute to its tensile strength
Superior and anterior walls of EAM and upper two-thirds of the external surface of TM
Innervated by the _____
Posterior and inferior wallsof EAM , and lower one-third of the external surface of TM:
Innervated by the ______
Internal surface of TM
Innervated by the ______
auriculotemporal nerve (branch of trigeminal nerve, CN V3).
auricular branch of the vagus nerve (CN X).
glossopharyngeal nerve (CN IX).
The middle ear lies within the ____ bone, and extends from the tympanic membrane to the lateral wall of the inner ear.
temporal bone
The main function of the middle ear is
to transmit vibrations from the tympanic membrane to the inner ear via the auditory ossicles.
The ___&___ partially extend upwards into the epitympanic recess.
malleus and incus
What’s tympanic cavity and epi tympanic recess
a space superior to the tympanic cavity, which lies next to the mastoid air cells
The _____ is the largest ossicle in d ear
malleus
What’s the buffer system of d middle ear
The mastoid air cells are located posterior to epitympanic recess. They are a collection of air-filled spaces in the mastoid process of the temporal bone
The mastoid air cells act as a ‘buffer system‘ of air – releasing air into the tympanic cavity when the pressure is too low.
There are two muscles which serve a protective function in the middle ear, they are
And how do they function
tensor tympani and stapedius
They contract inresponseto loud noise, inhibiting the vibrations of the malleus, incus and stapes
What’s acoustic reflex
contraction in response to loud noise, inhibiting the vibrations of the malleus, incus and stapes, and reducing the transmission of sound to the inner ear. This action is known as the acoustic reflex.
The tensor tympani and stapes orginates from
The tensor tympani originates from the auditory tube and attaches to the handle of malleus, pulling it medially when contracting
The stapedius muscle attaches to the stapes, and is innervated by the facial nerve.
______ equalisethe pressure of the middle ear to that of the external auditory meatus.
The auditory tube (eustachian tube)
What’s the auditory tube
The auditory tube (eustachian tube) is a cartilaginous and bony tube that connects the middle ear to the nasopharynx
The neck of the malleus lies against the flaccid part of the tympanic
membrane, and the handle of the malleus is embedded in the tympanic
membrane, with its tip at the umbo; thus, the malleus moves with the membrane
___ part of the ear is responsible for balance
Inner part
The inner ear can be divided into
Bony and membranous labyrinth
The bony labyrinth consists of
And is lined with
Vestibule, cochlear,3 semi circular canal
Lined with periosteom containing perilymph
The Membranous labyrinth consists of
And is filled with
It consists of the cochlear duct, semi-circular ducts, utricle and the saccule. The membranous labyrinth is filled with fluid called endolymph
Two parts of the membranous labyrinth; thesacculeandutricle, are located within the vestibule.
The inner ear has ____ openings into the middle ear
2
Oval and round
Theoval windowlies between themiddle earand the vestibule
whilst the round window separates the middle ear from the scala tympani (part of the cochlear duct).
The bony labyrinth is a series of bony cavities within the petrous part of the temporal bone.
The vestibule is the central part of the bony labyrinth. It is separated from the middle ear by the oval window, and communicates anteriorly with the __$ and posteriorly with the ____
cochlea and with semi-circular canals.
the auditory part of the inner ear is
Cochlear duct in membranous labyrinth
The cochlea houses the cochlea duct of the membranous labyrinth – the auditory part of the inner ear. It twists upon itself around a central portion of bone called the modiolus, producing a cone shape which points in an anterolateral direction. Branches from the cochlear portion of the vestibulocochlear (VIII) nerve are found at the base of the modiolus.
The presence of the _____ creates two perilymph-filled chambers above and below in cochlear
Which are
cochlear duct
Scala vestibuli: Located superiorly to the cochlear duct. As its name suggests, it is continuous with the vestibule
Scala tympani: Located inferiorly to the cochlear duct. It terminates at the round window.
There are ____ semi-circular canals
Which are
3
anterior, lateral and posterior.
What part of the bony and membranous labyrinth is responsible for balance
The semi-circular ducts, which are responsible for balance (along with the utricle and saccule).
Membranous Labyrinth consists of
cochlear duct, three semi-circular ducts, saccule and the utricle.
The cochlear duct is situated within the cochlea and is the organ of hearing.
vestibular apparatus consists of
The semi-circular ducts, saccule and utricle are the organs of balance (also known as the vestibular apparatus).
Write a short note on the inner ear fluids
The inner ear fluid, also known as the endolymph and perilymph, is a vital component of the human auditory and vestibular systems. It plays a crucial role in maintaining balance, spatial orientation, and hearing.
•Endolymph is found within the membranous labyrinth, which includes the cochlea (responsible for hearing) and the vestibular system (involved in balance and spatial orientation).The endolymph is crucial for transmitting sound vibrations and mechanical signals to the sensory cells within the cochlea and vestibular system.
•perilymph surrounds the membranous labyrinth and fills the bony labyrinth. It is similar in composition to cerebrospinal fluid, Perilymph helps protect the delicate structures of the inner ear, provides mechanical support, and facilitates the transmission of sound waves from the outer ear to the cochlea.
The membranous labyrinth is
The membranous labyrinth is a continuous system of ducts filled withendolymph.
The saccule and utricle are two membranous sacs located in the _____
vestibule
The utricle is the larger of the two, receiving the three semi-circular ducts. The saccule is globular in shape and receives the cochlear duct.
Explain the mechanism of hearing
1, Sound waves entering the external ear strike the tympanic
membrane, causing it to vibrate.
2, Vibrations initiated at the
tympanic membrane are transmitted through the ossicles of the
middle ear and their articulations.
3, The base of the stapes
vibrates with increased strength and decreased amplitude in the
oval window.
4, Vibrations of the base of the stapes create pressure waves in the perilymph of the scala vestibuli.
5,Pressure waves in the scala vestibuli cause displacement of the
basilar membrane of the cochlear duct
6.Movement of the basilar membrane
bends the hair cells of the spiral organ. Neurotransmitter is
released, stimulating action potentials conveyed by the cochlear
nerve to the brain.
6, Vibrations are transferred across the
cochlear duct to the perilymph of the scala tympani.
7, Pressure
waves in the perilymph are dissipated (dampened) by the
secondary tympanic membrane at the round window into the air
of the tympanic cavity.
