Chapter 9: (Module 10-The cochlea) Flashcards
bony labyrinth
a cavity that contains the inner ear; located within the petrous portion of the temporal bone.
membranous labyrinth
an endolymph-filled structure enclosed by the curves and coils of the bony labyrinth; the membranous labyrinth contains the semicircular ducts, utricle, saccule, and cochlea, which are connected via small communication channels.
cochlea
part of the inner ear that contains the sense organ of hearing (organ of Corti); the location which mechanical motions generated by sound are coded into nerve impulses for transition to the central nervous system.
organ of Corti
the sense organ of hearing that runs along the entire length of the basilar membrane; located on the scala media site of the basilar membrane.
basilar membrane
thinest and stiffest at the base of the cochlea
thickest and most flaccid at the apex
TONOTOPIC ORGANIZATION
the membrane that separates the scala media from the scala tympani; the organ of Corti is located on the scala media side of this membrane.
Held in place by the spiral ligament on one side and the spiral limbus on the other
scala media
Cochlear duct
filled with endolymph
the cochlear portion of the membranous labyrinth
scala tympani
filled with perilymph
connects with the scala vestibule at the helicortema located at the apex of the cochlea.
one part of the cochlear portion of the bony labyrinth; the scala tympani extends along the length of the cochlea from the helicotrema to the round window
scala vestibuli
filled with perilymph
continuous with the vestibule at the base of the cochlea
one part of the cochlear portion of the bony labyrinth; the scala vestibli extends along the length of the cochlea from the vestibule to the helicotrema.
helicortrema
a narrow passage at the apex of the cochlea at which the scala tympani and scala vestibule are connected.
perilymph
“peri”- out or around
the fluid that fills the bony labyrinth (scala vestibule and scala tympani of the inner ear); perilymph is high in sodium (Na) and low in potassium (K).
endolymph
“endo”- in
fluid located within the membranous labyrinth of the inner ear (in the scala media of the cochlea);this fluid is high in potassium (K) and low in sodium (Na).
base (of the cochlea)
the widest coil of the spiral of the cochlea
apex (of the cochlea)
the narrowest end of the spiral of the cochlea, where the scala tympani and scala vestibule join.
modiolus
bony core
the central bony channel of the cochlea within which the spiral ganglia are located.
spiral gaglia
the collection of cell bodies of the afferent auditor nerves; located in Rosenthal’s canal within the modiolus of the cochlea
spiral lamina
auditor nerve enters spiral lamina through holes called habenula perforata.
a spiral, corkscrew-shaped bony shelf that projects from the side of the modulus and partially divides the cochlear tunnel into smaller sections.
spiral ligament
a ligament that connects the basilar membrane with the lateral wall of the bony labyrinth
spiral limbus
the medial attachment point for Reissner’s membrane
Reissner’s membrane
the membrane that separates the scala media from the scala vestibule.
Rosenthal’s canal
*part of auditory nerve
channel in the center of the modulus through which the auditory nerve fibers travel.
tonotopic organization
the corresponded between stimulation frequency and place of stimulation along the cochlea.