17a. Inner ear. Bony and membranous labyrinth. Flashcards
What is the location of the inner ear?
In the petrous part of the temporal bone.
What are the parts of the inner ear?
- bony labyrinth
- membranous labyrinth
- ganglia and final branches of the vestibulocochlear nerve (VIII.)
What are the functions of the inner ear?
- hearing (cochlea, spiral organ of Corti)
- balance
- Spatial orientation
The bony (osseous) labyrinth
-> Identify
The bony (osseous) labyrinth
-> Identify
What are the Bony limbs (crura) of semicircular canals? (there are 5)
- 3 ampullary crura
- 1 simple crus
- 1 common crus
Left osseous labyrinth, lateral view
-> Identify
Left osseous labyrinth, lateral view
-> Identify
Left osseous labyrinth, lateral view
-> Identify
What are Maculae cribrosae?
perforated areas for entering the branches of the vestibular
nerve
-> They haver superior, media, inferior part
Innervation of Maculae cribrosae
- Sup - utriculoampullar nerve
- Media - Saccular nerve
- Inferior - Posterior ampullary nerve
Interior of the vestibule
-> Identify
The cochlea II.
-> Identify
The cochlea I.
-> Identify
The cochlea I.
-> Identify
The spiral canal of cochlea
-> Identify
The spiral canal of cochlea
-> Identify
The spiral canal of cochlea
-> Identify
The spiral canal of cochlea
-> Identify
The spiral canal of cochlea
-> Identify
Arterial supply of the membranous labyrinth
Venous supply of the membranous labyrinth
labyrinthine veins, v. of aqueduct of vestibule,v. of aqueduct of cochlea → inf. petrosal sinus → sigmoid sinus
The role of Perilymph
fills the bony labyrinth protecting the membranous one
Endolymph is drained by ___
by the endolymphatic duct into the dura matter venous sinuses
Perilymph is produced by ____
by the microvasculature of the periosteum
Perilymph is drained by ___
the perilymphatic duct into the
subarachnoideal space
The role of Perilymph
fills the bony labyrinth protecting the membranous one
The role of Endolymph
fills the membranous labyrinth,
Endolymph is produced by __
the stria vascularis (cochlea) and by the dark cells in semicircular duct
The role of Perilymph
fills the bony labyrinth protecting the membranous one
Sound waves in the perilymph, pressure equilibration
base of the stapes→fenestra vestibuli → scala vestibuli perilymph → cochlear duct and helicotrema → scala tympani perilymph → fenestra rotunda → secondary tympanic membrane
What are the 2 Receptors in the vestibular system?
- Cristae ampullares
- Maculae staticae
Receptors in the vestibular system
-> Describe the position of Cristae ampullares
- in the ampullae of semicircular ducts
- the ridge of the crista is always
perpendicular to the long axis of the duct
Receptors in the vestibular system
-> Describe position of macula
- in the utricle and saccule
- they lie in a perpendicular plane to each other
Receptors in the vestibular system
-> The role of macula
detect linear acceleration, tilt of the head and gravity
Receptors in the vestibular system
-> The role of Cristae ampullares
detect angular acceleration of the head.
What are the hair cells?
secondary sensory cell, mechanoreceptor
Differences between stereo cilia and kinoclium
Stereocilia
Kinocilium
Describe the basal part of the vestibular hair cells
- cell nucleus, synaptic vesicles (glutamate)
- synapses with afferents (peripheral processes of bipolar ganglionic cells)
- efferent fibers from the brain, modulation of sensitivity
The structure of the macula
-> Identify
The structure of the ampullary crest
-> Identify
