Histology II: the inner ear Flashcards
The inner ear consists of what 2 main parts?
two labyrinthine compartments, one contained within the other:
Bony labyrinth
Membranous labyrinth
The bony labyrinth consists of what 3 connected structures?
the semicircular canals
vestibulae
the cochlea
The bony labyrinth is found within what bone?
the temporal bone
What are the semicircular canals?
three tiny, fluid-filled interconnected tubes that lie at right angles to each other and are vestibular organs for balance
What are the vestibulae of the inner ear?
the central part of the bony labyrinth behind the cochlea, and in front of the three semicircular canals
it contains utricle and sacculae of the membranous labyrinth.
What is the cochlea of the inner ear?
is a bony canal that runs spirally around its axis, is involved in hearing
Where is the membranous labyrinth found?
its suspended within the bony labyrinth
What divisions does the membranous labyrinth consist of?
The cochlear labyrinth
and
The vestibular labyrinth
The cochlear labyrinth includes what structure?
the cochlear duct
The vestibular labyrinth includes what structures?
semicircular ducts, utricle and saccule
What is the utricle of the membranous labyrinth?
is a component of the vestibular system found within the membranous labyrinth of the ear
detects motion in the horizontal plane
What are the sacculae of the membranous labyrinth?
is a bed of sensory cells found within the membranous labyrinth of the inner ear
detects motion in the vertical plane
Name 3 types of sensory cells of the membranous labyrinth.
Cristae ampullaris
maculae
The spiral organ of Corti
Name 3 types of sensory cells of the membranous labyrinth.
Cristae ampullaris
Maculae
The spiral organ of Corti
Where can cristae ampullaris be found and what is their function?
are located in the membranous ampullae of the semicircular ducts.
the sensory organ of rotation, they sense angular acceleration and deceleration.
Where can the maculae be found and what is their function?
Two maculae, one in the utricle and the other in the saccule
sense the position of the head and its linear movement
What is the spiral organ of Corti and where can it be found?
Also known as the spiral organ is found in the cochlear duct.
hearing organ/ sound receptor
The Bony cochlear canal has what 2 parts?
scala vestibuli (vestibular duct) and scala tympani (tympanic duct)
What are scala vestibuli and -tympani filled with?
perilymph
an extracellular fluid the ionic composition of which is comparable to that of plasma and cerebrospinal fluid.
Where are scala vestibuli and -tympani found?
within the bony cochlear canal
What is the cochlear duct (scala media)?
an endolymph-filled cavity located between the scala vestibuli (upper) and the scala tympani (lower) in the cochlea
What separates the cochlear duct from the vestibular-?
the vestibular membrane (also known as Reissner’s membrane)
What forms the outer wall of scala media?
Stria vascularis including the spiral ligament
The tympanic wall of the cochlea is formed by?
Spiral bone plate/spiral limbus and basilar membrane, on which the Organ of Corti is located, altogether form the tympanic wall.
The cochlea main 3 divisions?
scala vestibuli
scala media (cochlear duct)
scala tympani
What is thickening of the spiral bone plate of the tympanic wall called?
the spiral limbus
Where can the cochlear nerve be found?
runs in the axis of the cochlea
What structure does the tectorial membrane belong to?
The organ of Corti
Where does the tectorial membrane extend?
extends from the spiral limbus into the cochlear duct (scala media)
What forms the base of the organ of Corti?
the basilar membrane of the cochlea
The organ of corti contains what 5 cell types?
Sensory hair cells
The rest are supportive cells: Border cells Outer supportive cells Phalangeal cells Pillar cells
What are transformed into waves of the perilymph within the inner ear?
the vibrations of the ossicles
Where are sound vibrations sent onward from the perilymph?
they’re transmitted trough the vestibular membrane to the cochlear duct, which contains endolymph
What initiates neuronal transduction for sound?
Movements of the stereocilia of the hair cells in the cochlear duct.
Basic path for sound (name 6 steps).
tympanic membrane ossicles perilymph of the scala vestibuli and -tympani endolymph of cochlear duct stereocilia of organ of corti spiral ganglion
