Ear Flashcards
Function of the ear
Hearing and balance or vestibular
Outer ear pinnacle
This captures sound waves and channels it through the auditory canal
The sound waves terminates
On the tympani membrane the tympani membrane as sound hits it and you get vibration of the ear drum
Vibration of the ear drum involves
Mechano transduction
In the middle ear there are bony structures called
Ossicles, the maleus(hammer), incus(anvil),stapes(stirrup)
What structure is the malleus, incus, and stapes connected to
The maleus and the incus are connected the the tympanic membrane, while the stapes is connected to the oval window
Eustachean tube
It is a structure in the middle ear that regulates pressure or ear pressure, it makes sure that the pressure is the same as the atmospheric pressure…it communicates neuropharnx and connects the throat to the ear
Function of the inner ear
Sound transduction and balance
The cranial value of the
Temporal bone
Osseus labyrinth
This a bony labyrinth that is hallowed out in the inner ear
Membrane labyrinth
This labyrinth follows the cincture of the osseus labyrinth all the activity of the inner ear occurs here
Sound transduction
It occurs in a part of the memebranous labyrinth called the cochlear duct
Cochlear
In the osseous labyrinth that forms the cochlear duct that is the membranous labyrinth
Cochlear duct consist of
Scala vestibuli , scala media this is where sound is transduce, and scala tympani. They are fill with perilymph, endolymph
Organ of corti
Located in the scala media, this is where sound is going to be transduced. It consist hair cell not true hair cells
The hair cells in the organ if corti
Not true hair cell outer hair cells and inner hair cells.
The outer hair and inner hair will synaptically be linked to receptors that carry the Information via
Cranial nerve 8 vestibular cochlear nerve
The vestibular nerve has two branch
One that goes up the cochlear and other goes to the vestibular apparatus ( balance)
description of the organ of corti
There are sterocilla which are elongation of the hair cells . There is an overlying gelatin membrane called the tectorial membrane on top and at the bottom there is the basilar fiber
Explain the transduction of these cells
The basilar fiber vibrates upward pushing the hair cells against the tectorial membrane and compresses them, in response the cells depolarizes, fires, and release neurotransmitter that activates the nerve fiber
Most transduction is done in
Inner ear that is 90% of the inner hair cells and outer cell 10%
What happens if outer hair cells are destroyed
Hearing is impaired, conclusion is that this out hair cells are need for sensitivity
The function of the oval window
Accommodates as increase in pressure, an oval window and a round windows is need so that membrane structure of the inner ear is not broken
The frequency and the amplitude or pitch of the sound is due to
To which area of the basilar fiber that is easily affected, these are difference parts of the this membrane that are specialized for pitch determination
High frequency are located
In front part of the ear, middle, and lower part of the ear
Amplitude has many effects which are
1 one is that it change the frequency of the action potential 2 has a summation effect on hair cell causing more hair cells to be activated you get a summation effect of what happening to the signal
The flow of sound transduction
It starts in scalar media associated with organ of corti involving the hair cells and the tectorial membrane and basilar membrane… This is mechano transduction mechano receptor are involved association , brain stem , to hypothalamus
There two type the deafness
Conduction deafness and nerve deafness
Conductive deafness
Impairment of physical structure of the ear tympani membrane, ossicles that conduct sound itself cochlear, fibrosis, otosclerosis
Nerve deafness
Caused by impairment of cochlear or impairment of auditory nerve
Fibrosis
Cuts down flexibility of the tympanic membrane, that does not allow for the vibration of ossicles
Otosclerosis
Bony material begin to fail in around the space of ossicles, over time they can’t vibrate any more
Vestibuli labyrinth
Follows the couture of the osseus, there are the saccule and utricle in the first part of the cochlear where saccule and utricle is associated with static balance of head
Saccule
Position of the head when you lying down
Utricle
Position of the head when vertical or standing up
Semicircular duct
Associated with movement of head
Crista ampullaris
This receptor site or receptor structure, sensory structure is inside this structure, they will only fire when the cupula is distorted or pushed
Endolymph fluids in crista ampullaris
Move through the hair cells to induce a transduction
Vestibular apparatus
Balance and equilibrium, saccule and utricle and semicircular duct
Maculae
The sensory area in the saccule and utricle, this are also hair cells called the vestibular cilia
Otoliths
The gelatinous area that has calcium carbonate crystals
The hair cells in the maculae will fire
Due to the compression of the stereo cilia on the kinocilium this is based on gravity the nerve fiber will fire neurotransmitter will release and the message is sent to the cranial nerve 8. Bending in one direction lead to depolarization and the other hyperpolarization
Ampullae
Houses the receptor cells, crista ampullaris
