Ear and Auditory Pathway Flashcards
The ear can be divided into 3 parts, what are they called?
1 - external, middle and inner ear
2 - external, superior and inner ear
3 - lateral, middle and inner ear
4 - lateral, middle and medial ear
1 - external, middle and inner ear
The ear can be divided into 2 parts, the external, middle and inner ear. The external ear has 2 main parts, using the 2 labels below, label numbers 1 and 2:
- Pinna (auricle)
- External auditory meatus/canal
1 - Pinna (auricle)
2 - External auditory meatus/canal
The ear can be divided into 3 parts, the external, middle and inner ear. The middle ear has 4 main parts, what are they?
1 - Tympanic membrane
2 - Ossicles
3 - Mastoid cells
4 - Pharyngotympanic (Eustachian) tube
The ear can be divided into 3 parts, the external, middle and inner ear. The internal ear has 2 main parts, label them on the image below:
1 - Cochlea
2 - Vestibular apparatus
The ear is closely related to which bone of the cranium?
1 - frontal bone
2 - occipital bone
3 - zygomatic bone
4 - temporal bone
4 - temporal bone
- petrous part of temporal bone is important as it houses inner and middle cavities
- also has mastoid air cells
What is the pinna, also referred to as the auricle of the ear?
- the visible part of the ear outside of the head
What is the auditory canal of the ear?
- a pathway running from external to middle ear
- essentially the hole we can see inside
What is the tympanic membrane, also referred to as the eardrum of the ear?
- tympanic means drum of the ear due to how it looks
- separates outer and middle ear
- thin layer of tissue in the human ear that receives sound vibrations from the outer air and transmits them to the auditory ossicles
The outer ear is composed of the Auricle / pinna, Auditory Canal and Tympanic membrane. What are the functions of the external ear?
1 - collects sound waves
2 - auditory canal transmits sounds
3 - sounds converted into vibrations at tympanic membrane (mechanical -> electrical impulses)
The pinna/auricle is composed of cartilage and has 4 major regions, using the labels below, label numbers 1-4:
- tragus
- helix
- lobule
- antihelix
1 - helix
2 - antihelix
3 - tragus
4 - lobule
The pinna/auricle is composed of cartilage and has 4 major regions, the helix, antihelix, tragus and lobule. What is the main purposes of the pinna?
- collect and amplify sound
- E for Ear, and E for Elastic
The auditory canal is the second part of the external ear that transmits sound to the tympanic membrane. What proportion of this is composed of cartilage and bone?
- first 1-3 = cartilage
- inner 2/3 = bone (temporal to be specific)
The auditory canal is the second part of the external ear that transmits sound to the tympanic membrane. The first 1/3 is composed of cartilage and inner 2/3 are composed of bone. What covers the auditory canal?
- skin and hair
- reduce risk of things getting into the ear
The auditory canal is the second part of the external ear. The first 1/3 is composed of cartilage and inner 2/3 are composed of bone. It is covered by skin and hair, but also possess a specific gland. What are these glands called and what is their function?
1 - ceruminous glands that secrete mucus
2 - ceruminous glands that secrete ear wax
3 - ceruminous glands that secrete hair
4 - ceruminous glands that secrete WBCs
2 - ceruminous glands that secrete ear wax
The tympanic membrane, also referred to as the ear drum separates the external from the middle ear. How does the tympanic membrane transmit the sound waves that help us hear sounds?
- sound waves causes tympanic membrane to vibrate
- vibrations are transmitted to the ossicles (bones)
There are 3 tiny bones in the middle ear, called the ossicles. Label these 3 bones in the image below using the labels below:
- stapes (latin for stirrup as it looks like one)
- malleus (latin for hammer as it resembles one)
- incus (anvil in latin as it resembles one)
1 = malleus (latin for hammer as it resembles one)
2 = incus (anvil in latin as it resembles one)
3 = stapes (latin for stirrup as it looks like one) SMALLEST BONE IN THE BODY
There are 3 tiny bones in the middle ear, called the ossicles. The mnemonic MIS can be used to remember there order and names from external to internal. What are the 3 bones called?
M = Malleus (latin for hammer as it resembles one)
I = Incus (anvil in latin as it resembles one)
S = Stapes (latin for stirrup as it looks like one) SMALLEST BONE IN THE BODY
There are 3 tiny bones in the middle ear, called the ossicles. These 3 bones are the malleus, incus and stapes. How does the tympanic membrane transmit sound to these bones and then onto the inner ear?
- sound waves causes tympanic membrane to vibrate
- vibrations are transmitted to malleus, then incus and then stapes
- stapes transmits vibrations to oval window and into inner ear
The middle ear contains the ossicles. What is this space surrounding this area filled with and what skull bone is this space within?
1 - filled with air inside the temporal bone
2 - filled with ear wax inside the temporal bone
3 - filled with mucus inside the temporal bone
4 - filled with hair inside the temporal bone
1 - filled with air inside the temporal bone
The middle ear contains the ossicles. This is a space filled with air within the temporal bone. What 3 places does the middle ear communicate with?
- inner ear (oval window) and cochlea
- nasopharynx via eustachian tube
- mastoid process (contains mastoid air cells)
The mastoid air cells are located within the mastoid process of the temporal bone in the posterior region of the middle ear. What are the 3 potential functions of the mastoid air cells?
- protect the delicate structures of the ear
- regulate ear pressure
- protect the temporal bone during trauma.
If the ear becomes infected and this infection cannot be contained within the ear, there is a chance this infection could spread to the posterior region of the middle ear called the mastoid air cells. What is this called and why is this dangerous?
- mastoid process
- if infected it is called the mastoiditis
- the infection can spread to the brain
There are 2 muscles in the middle ear, what are they called?
1 - tympani and obturator
2 - stapedius and obturator
3 - gracillus and stapedius
4 - stapedius and tympani
4 - stapedius and tympani
- tympani innervated by tympani nerve (CN V, mandibular branch) moves tympanic membrane
- stapedius - innervated by the facial nerve and moves the stapes bone
There are 2 muscles in the middle ear, called the tympani and the stapedius. What is the function of these muscles?
- protect the ear from loud noises by contracting
- tympani tightens the tympanic membrane so malleus does not vibrate
- stapes is pulled away from oval window so no transmission of vibrations to inner ear
There are 2 muscles in the middle ear, called the tympani and the stapedius. These muscles protect the ear from loud noises by contracting in response to loud noise. This contraction inhibits the vibrations of the malleus, incus and stapes and reduces transmission to the inner ear. What is this reflex called?
1 - stretch reflex
2 - clasp knife reflex
3 - golgi tendon reflex
4 - acoustic reflex
4 - acoustic reflex
The eustachian tube, also called the auditory tube is a cartilaginous and bony tube that connects the middle ear to the nasopharynx. It has 2 functions, one of which relates to infection from the nasopharynx. How does the eustachian tube do this?
- closes and restricts fluids from moving into the middle ear from the nasopharynx
The eustachian tube is considered part of the middle ear and connects the middle ear and the nasopharynx. It has 2 main function. One of these is to remain closed and ensure infection does not move from the nasopharynx into the middle ear. What is its second function?
1 - maintains clean air in middle ear
2 - equalises air in middle ear
3 - enhances vibrations in middle ear
2 - equalises air in middle ear
- equalises air in the middle ear due to external pressure changes, such as during flying or diving.
- during a flight air pressure in the outer ear increases,
- middle ear pressure forces tympanic membrane to bulge
- the eustachian tube opens, letting air out of the middle ear to equalise the pressure
- can work in reverse if outer ear pressure is higher
The 3 ossicles (malleus, incus and staple) are held together by what type of joint?
1 - suture
2 - cartilaginous joint
3 - synovial joints
4 - sesamoid joint
2 - synovial joints
The facial nerve runs in close proximity to the middle ear. It enters the internal acoustic meatus and passes into the facial canal. Inside the middle ear, a branch from the facial nerve bifurcates. What is this nerve called?
1 - temporalis nerve
2 - zygomatic nerve
3 - chorda tympani
4 - masseter nerve
3 - chorda tympani
- provides information from anterior two-thirds of the tongue about taste
- branch of facial nerve
The facial nerve runs in close proximity to the middle ear. It enters the internal acoustic meatus and passes into the facial canal. Inside the middle ear, a branch from the facial nerve bifurcates, called the chorda tympani. The facial nerve then passes through the middle ear and out through which foreman?
1 - stylomastoid foramen
2 - jugular foramen
3 - foramen ovale
4 - foramen magnum
1 - stylomastoid foramen
- stylo = styloid process
- mastoid = mastoid process
- foreman sits in between stylo and mastoid processes below the ear
In adults the eustachian tube is diagonal, but in children this is more horizontal. Why is this important?
- eustachian tube is shorter, narrower, and more horizontal in children
- increases the risk of infection
What is the smallest muscle in the body?
1 - tympani muscle
2 - stapedius muscle
3 - gracillus muscle
4 - pectinate muscle
2 - stapedius muscle
- stapedius of the ear connects to stapes
- when contracts it closes due to increased pressure
- like when on a plane or deep water
In the inner ear there are 2 main parts which end with labyrinth, what are their 1st names?
1 - bony and subcutaneous labyrinth
2 - membranous and bony labyrinth
3 - bony and tympanic labyrinth
4 - membranous and tympanic labyrinth
2 - membranous and bony labyrinth
In the inner ear there are 2 main parts, called the bony (or osseous) and membranous labyrinth. Each of these is fluid filled. What is the fluid in each of these called?
- bony (or osseous) = perilymph
- membranous = endolymph
In the inner ear there are 2 main parts, called the bony (or osseous) and membranous labyrinth containing perilymph and endolymph. What are the 2 functions of these fluids in the inner ear?
1 - balance
2 - hearing
In the inner ear there are 2 main parts, called the bony (or osseous) and membranous labyrinth containing perilymph and endolymph, which are important for balance and hearing. Which part of the temporal bone can these be located?
- petrous bone
- part of the temporal bone
The inner ear is composed of 3 parts, label them in the image below using the following:
vestibule
cochlea
three semicircular canals
1 = semilunar canals (balance)
2 = vestibule
3 = cochlea (hearing)
There are a number of ducts in the inner ear, using the labels below, label the image:
- cochlear duct (ductus cochlearis)
- utricle
- saccule semicircular ducts
- anterior
- posterior
- common (lateral)
- semicircular ducts
1 = semicircular ducts
2 = anterior
3 = common (lateral)
4 = posterior
5 = utricle
6 = saccule
7 = cochlear duct (ductus cochlearis)
The cochlea is important for hearing. Inside the cochlea there are 3 compartments. Using the names below, label the image below:
- scala tympani
- cochlear duct
- scala vestibular
1 - cochlear duct
2 - scala vestibular
3 - scala tympani
The cochlea is important for hearing. Inside the cochlea there are 3 compartments. The layers of these compartments can be remembered using the mnemonic SCS. What are the 3 layers from top to bottom using this mnemonic?
S = scala vestibular
C = cochlear duct
S = scala tympani
The cochlea is important for hearing. Inside the cochlea there are 3 compartments, cochlear duct (in the middle, also called the scale media), scala vestibular (on top) and scala tympani (at the bottom). Each of these parts contains either perilymph or endolymph. Which areas contain which fluid? (remember PEP)
- scala vestibular = perilymph
- cochlear duct = endolymph
- scala tympani = perilymph
When sound travels down the ear canal it causes vibrations that are then transferred to the tympanic membrane. These then transfer the vibrations to the ossicles (malleus, incus and staple in that order) and into the oval window. Once these vibrations reach the oval window, how is this then transferred to the cochlear duct (scala media)?
- vibrations cause motion of the perilymph in scala vestibule and the scala tympani
- vibrations are transferred to the membranes of the scala vestibule (superior = vestibular membrane) and inferior = basilar membrane)
- vibration of the scala vestibule membranes creates motion of the endolymph inside the scala vestibule
When sound travels down the ear canal it causes vibrations that are then transferred to the tympanic membrane. These then transfer the vibrations to the ossicles (malleus, incus and staple in that order) and into the oval window. Once these vibrations reach the oval window, they are transferred, causing motion of the perilymph in scala vestibuli. The scala vestibuli transfers the motion to the endolymph in the cochlear duct creating waves in the basement membrane of the cochlear duct. How does this generate the sensation of sound?
- waves in the basement membrane causes the hairs in the organ of corti to bend and move
- bending of hairs causes an action potential
When sound travels down the ear canal it causes vibrations that are then transferred to the tympanic membrane. These then transfer the vibrations to the ossicles (malleus, incus and staple in that order) and into the oval window. Once these vibrations reach the oval window, they are transferred, causing motion of the perilymph in scala vestibuli. The scala vestibuli transfers the motion to the endolymph in the cochlear duct creating waves in the basement membrane of the cochlear duct. Waves in the basement membrane causes the hairs in the organ of corti to bend and move, creating an action potential. This is transferred to the auditory branch of which cranial nerve?
- cranial nerve VIII (8) vestibulocochlear nerve
Following the transfer of vibrations to the hearing receptors, which generates the sensation of sound along the auditory nerve of cranial nerve VIII (8) the vestibulocochlear nerve, what happens in the third part of the cochlea, the scala tympani, as continued vibrations may be detrimental to hearing?
1 - pressure waves travel along scala tympani and are dampened at the round window
2 - pressure waves travel along scala vestibuli and are dampened at the round window
3 - pressure waves travel along scala vestibuli and are dampened at the oval window
4 - pressure waves travel along scala tympani and are dampened at the oval window
1 - pressure waves travel along scala tympani and are dampened at the round window
- balances pressure in the cochlea
The vestibule is a communication part of the inner ear sitting between the semicircular canals and the cochlea. What is the purpose of the vestibule?
- important for balance (change in head position)
- central part of the bony labyrinth
- contains fluid filled sacks of perilymph (utricle, capula, ampulla and saccule)
The semicircular canals contained within the bony (osseous) labyrinth (posterior, anterior, middle) all contain endolymph and have one end that has a swelling, what is this swelling called, and what is the importance of these swellings?
1 - cupula
2 - ampullas
3 - macula
4 - ducts
2 - ampullas
- hair receptors in ampulla are able to detect movement of endolymph
- movements include changes in position, speed etc
- these receptors relay this message to the brain
The ampulla are swellings located at the end of each of the semicircular canals (posterior, anterior and lateral). These are set at 90 degrees to one another. What is the importance of having the semicircular canals at 90 degrees to one another?
- so we can detect changes in 3 dimensional space
The ampulla are swellings located at the end of each of the semicircular canals (posterior, anterior and lateral). These are set at 90 degrees to one another allowing us to detect movement in 3 dimensional space. How are the ampulla able to detect changes in position?
1 - contains voltage gated channels that open when movement is detected
2 - contains ligand gated channels that open when movement is detected
3 - contains hair cells on ampulla crest that detect changes in endolymph movement
4 - contains hair cells on ampulla crest that detect changes in perilymph movement
3 - contains hair cells on ampulla crest that detect changes in endolymph movement
- hair cells moving creates an action potential
The ampulla are swellings located at the end of each of the semicircular canals (posterior, anterior and lateral). These are set at 90 degrees to one another allowing us to detect movement in 3 dimensional space. When we move and change position the fluid contained within them, called endolymph moves, which is detected by balance receptors called hair cells on the ampulla crest. The hair cells are stimulated causing an electrical signal. Which nerve then transmits this signal to the brain?
- vestibular branch of cranial nerve VIII (8)
- the vestibulocochlear nerve
Within the ampulla we have hair cells that are able to detect change in position due to the movement of the endolymph. There is a small dome within the ampulla that cover the hair cells that help detect movement, what are these called?
1 - ampulla
2 - crista ampullaris
3 - cupula
4 - ganglion
3 - cupula
The vestibule is the middle region of the inner ear, sitting between the semi-circular canals and the cochlea. Within the vestibule there is the utricle and saccula, which are filled with endolymph. There is a region within these that contain balance receptors. What are these regions called?
1 - ampulla
2 - crista ampullaris
3 - cupula
4 - macula
4 - macula
- essentially changes in head position from horizontal to vertical acceleration
What is the organ of Corti?
- receptor organ for hearing
- located in the cochlear duct, also known as scala media
How does the organ of Corti, the receptor organ for hearing located in the cochlear duct become stimulated?
- vibrations move through scala vestibule and scale tympani and out of the round window
- before reaching the round window, vibrations in the scale tympani move the basement membrane
- basement membrane moves and stimulate hearing
When we are talking about the peripheral auditory pathway, what are the 3 parts we need to refer to?
1 - outer ear
2 - middle ear
3 - inner ear
When we are talking about the central auditory pathway, what are the 3 main parts of the CNS we need to refer to?
1 - brainstem
2 - midbrain
3 - cerebrum
What is the gold standard for assessing a patients sensorineural hearing loss?
1 - rinnes test
2. -webers test
3 - crude hearing test
4 - audiogram
4 - audiogram
Cranial nerve VIII (8) the vestibulochochlear nerve provides stimulus relating to hearing and balance. When the cochlea transmit a signal for sound, where is the signal transmitted to?
- cochlear nuclei located in the medulla where they synapse with 2nd order neuron
- 2nd order neuron decussation (crosses to other side of the brain)
- 2nd order neuron synapses with 3rd order neuron at the inferior colliculus in midbrain
- 3rd order neurons then synapse in thalamus with 4th order neurons
- 5th order neurons then travel to auditory cortex in the temporal lobe
The auditory cortex in the temporal lobe is important for providing hearing sensations. Which broadmann areas are these?
1 - broadmann area 4
2 - broadmann areas 1, 2 and 3
3 - broadmann areas 17
4 - broadmann areas 41 and 42
4 - broadmann areas 41 and 42
