Anatomy lecture #7 the ear recording Flashcards
three parts of the ear, AKA the Vestibulocochlear Organ organ
the external ear
the middle ear- medial to the eardrum
the internal ear- most medial and deepest of all of the parts
the external ear
has the auricle- which is the fan shape part of the ear that is made of all cartilage
and it has the external acoustic meatus which is the hole into the ear
external auditory canal is half ___ and half ___
half bone (medial portion) half cartilage (lateral portion)
what is cerumen?
ear wax- in older people it can impede the sound. So it can clog the external ear canal
middle ear is also called the
Tympanic Cavity ( think of it as a room you’re standing in)
Ossicles
vibrate whenever we transmit sound into the ear. They relay this to where it can be transmitted to electrical energy, and it’s carried by the 8th cranial nerve to the brain
Tympanic Membrane
membrane of the ear drum
Tegmen Tympani
the roof over the middle ear
Epitympanic Recess
extension into upper right middle ear
layers of eardrum (tympanic membrane)
lateral layer is skin
middle layer is connective tissue
median side = mucus membrane
the umbo
it’s the end an ossicle that is attached to the medial side of the eardrum
malleolus
the actual ossicle that attaches to the medial side of the eardrum
what is the opening at the base of the cochlea called?
Fenestra Vestibuli (Oval Window)
Fenestra Cochlea (Round Window) location
underneath the fenestra vestibule
tensor tympani muscle innervated by
V3
tensor tympani runs parallel to
auditory (eustachian) tube
what does the tensor tympani do
it dampens the vibration of the malleus so that it isn’t top loud for us
auditory tube connects what to what
middle ear to nasal pharynx
auditory tube runs
down, medially, and anteriorly
lateral 1/3rd of auditory tube is
bone
medial 2/3rd of auditory tube is
cartilage
nasal pharynx connects to what part of the auditory tube
the cartilaginous portion.
tube of elevation with tubal tonsils
young subjects have the tubal tonsils which is lymphoid tissue
pr
where the stypidius (smallest muscle in body) muscle originates. It is innervated by cranial nerve 7
importance of the Stapedius muscle (CN VII
the stapedius muscle has a tendon that attaches into the stapes bone (horseshoe shape structure) that plugs into the oval window( Fenestra Vestibuli) and it transmits the sound from the middle ear into the inner ear
importance of the Stapedius muscle (CN VII
the stapedius muscle has a tendon that attaches into the stapes bone (horseshoe shape structure) that plugs into the oval window( Fenestra Vestibuli) and it transmits the sound from the middle ear into the inner ear
malleus looks like a
a hammer with a long handle called the manubrium. 1st ossicle in chain
the umbo is
the tip of the manubrium of the malleus, it’s where the malleus connects into the eardrum
the incus
2nd one in chain to vibrate
the stapes
3rd one in chain to vibrate. Prevents over vibrating
explain order of vibrations
- tympanic membrane
- causing malleus to vibrate
- causing incus to vibrate
- causing stapes to vibrate
- magnify vibrations with each bone.
lower ear nerve
glossopharyngeal (specifically, tympanic nerve or Jacobson’s nerve)
fascial nerve of ear
called the chorda tympani
Cochlea is for
Hearing
Vestibule is for
Static Equilibrium
3 Semicircular Canals are for
Kinetic Equilibrium
3 Semicircular Canals are for
Kinetic Equilibrium
the boney labyrinth encases the
membranous labyrinth
the membranous labyrinth inside of the cochlea is called the
cochlear duct
the sacule and lutricle
the membranous labyrinth’s inside of the vestibule
membranous labyrinth of the semicircular canals are
the semicircular ducts
the membranous labyrinth houses the
Receptors for Hearing and Equilibrium
within the cavity of the membranous labyrinth there’s a the fluid called ____. and what does it do?
Endolymph- they can stimulate the sensory endings to make us feel balance or unbalanced
displacement of ___ stimulates sensory endings to make us feel balanced or unbalanced
endolymph
which nerve takes the information from the membranous labyrinth into the brain? and how does it do this?
cranial nerve 8 takes it to the brain
the mechanical energy of the inner ear is converted using sensory receptors within membranous labryinth, to become electrical energy which can travel with cranial nerve 8 into the brain
Between boney and membranous labyrinth is what fluid?
Perilymph-Fluid
What are the spaces between the boney and membranous labyrinth named?
Scala Vestibuli (top) Scala Tympani (bottom) - we find Perilymph-Fluid in these
What separates the Scala Vestibuli (top) from the Scala Tympani (bottom)
osseous spiral lamina
the osseous spiral lamina has a little structure with a little hat on it called
the organ of hearing (the organ of corti)
the space around the organ of corti is called
the cochlear duct
the cochlear duct is inside the membranous labyrinth and that’s where the
endolymph is
what is found in the Scala Vestibuli and
Scala Tympani
- we find Perilymph-Fluid in these
spiral organ or organ of corti is where we
convert mechanical energy into electrical energy that can go with cranial nerve 8 into the brain
summary of hearing
Tympanic Membrane Vibrates
Vibration of the Ossicles (malleus-incus-stapes)
Stapes vibrates the Perilymph
Perilymph conveys vibrations to Endolymph (mechanical to electrical via the spiral organ/ organ of corti)
Simulation of Auditory Sensory Endings that project to CN VIII
the stapes plugs into the
oval window
the ampullae of the semicircular canal
the swellings which are where the receptors are to form the kinetic labyrinth to check rotational movements of head
Saccule & Utricle have sensory epithelium called the
Maculae
what stimulates the Maculae? What happens when stimulated?
Gravitational changes stimulate sensory endings that project to CN VIII
maculae has little hair cells with a little membrane that overlies it. The membrane is called Otolithic. It has little holes in it. If hair cells are bent, what happens?
mechanical energy is converted to electrical energy used by cranial nerve 8
kinetic labyrinth are inside of semicircular canals. Their Ampullae swellings have sensory epithelium called
Ampullary Crests
When we get changes in endolymphatic flow (so rotation of the head) in the ampullary crests, it stimulates
sensory endings that project to CN VIII
