Unit 1.1 Anatomy and Physiology Flashcards
(30 cards)
Outer ear is made up of? (3)
- Pinna 2. External Auditory Meatus 3. Tympanic Membrane
Middle ear is made up of? (4)
- Ossicles - Malleus, Incus, Stapes
The inner ear is made up of (3)
- Vestibular Labyrinth 2. Cochlea 3. Auditory Labryinth
The Outer, Middle, and Inner ear are what kinds of energy?
Outer= Acoustic Energy (sound waves)
Middle=Mechanical Energy (ossicles)
Inner=Fluid Energy (firing of auditory nerve)
In technical terms - how do we hear?
Acoustic Sound energy enters the ear > into external auditory meatus > hits tympanic membrane (eardrum) >Mechanical energy vibrates ossicles > fluid energy enters cochlea > cochlea hair cells generate nerve impulses > auditory nerve carries to brain
Hearing loss in the outer and middle ear is know as?
conductive hearing loss
Hearing loss in the inner ear is known as?
sensorineural
What is Peripheral HL vs. Central HL?
Peripheral is outer ear through 8th nerve —Central is brainstem through cortex.
Neural pathology can also be called?
retrocochlear
What is the function of the Auricle?
The external auditory meatus with the outer third being ear wax and hair follicles. Inner 2/3 is boney structure with osseocartilaginous junction (area where cartilage meets bone) and tympanic membrane.
What is physiology of the Outer ear ? (3)
- Protective mechanism for middle and inner ear. 2. Collects and boosts high frequency sounds 3. assists in sound localization
Name the 3 smallest bones in the middle ear and which is connects to oval window?
- malleus 2. Incus 3. Stapes
stapes is connected to oval window.
The ossicles are suspended in middle ear cavity and function like a piston (mechanical) pushing sound waves to inner ear fluids
The middle ear has two muscles that protect against loud sounds entering, what are they?
- Tensor Tympani (attached to malleus and innervate 5th cranial nerve) 2. Stapedius (attached to stapes and innervate 7th cranial nerve) By limited movement of ossicle, they reduce pressure to oval window
In the middle ear, what does the impedance mismatch transformer do?
It matches the energy between air and fluid. It increased 30 dB. The areal ratio is going from TM to OW (Big to little space)
What equalizes pressure between the middle ear cavity and nasopharynx?
Eustachian tube - also allows for drainage. it is flat as infant and drops as adult
What does the auditory labyrinth and vestibular labyrinth contain?
Auditory contains cochlea *for Hearing
Vestibular contains fluid filled canals *For Balancing
What are the 3 chambers of the cochlea and their fluids?
Scala vestibuli-perilymph
Scala media- Endolymph
Scala tympani -perilymph
Is the cochlea was rolled out, what frequency is at the base, and what frequency is at the apex?
base = high freq
apex - low freq.
Which membrane is between scala media and scala tympani?
Basilar membrane
What sits on top of basilar membrane, and below tectorial membrane (inside scala media)?
organ of corti
What is the turning point for scala vestibuli and scala tympani called?
helicotrema
The organ of corti contains sensory cells for hearing. What are the inner and outer hairs cells for?
inner hair cells - for clarity - 1 row
outer hair cells - for intensity - 3-4 rows
inner ear physiology - what does the inner ear do?
creates waves and fluid moving the hair cells - allows chemical exchange. Vibration of the oval window causes this wave to move scala vestibuli and pushes down to scala media & scala tympani and comes out round window. The wave established at basilar membrane moves from apex to base and brain makes sense of information.
What is a cochlea wrapped around?
It is wrapped around a core called modiolus
