THRC.19 Flashcards
Components of the internal ear
Membranous labyrinth
Interconnected series of membranous fluid-filled ducts
Fluid inside the membranous labyrinth
Endolymph
The components of the membranous labyrinth
- Vestibular labyrinth (balance)
- Cochlear labyrinth (hearing)
Vestibular and cochlear labyrinth communicate through…
Ducts reuniens
The membranous labyrinth is surrounded by…
Osseous labyrinth
Components of the bony labyrinth
- Vestibule
- Semicircular canals
- Cochlea

Osseus labyrinth (dog)

Cochlea

Vestibule

Osseous ampulla

Anterior semicircular duct

Lateral semicircular duct

Common crus

Posterior semicircular duct
The cochlea forms a spiral shape around…
Modiolus (hollow core of bone)
- This contains the cochlear nerve
What is shown?

Cross section of a cochlea

Helicotrema

Spiral lamina (shelf structure)

Modiolus
Containing the cochlear nerve
The spiral lamina incompletely splits the lumen into which two portions?
- Scala tympani
- Scala vestibuli
What is found in the spiral lamina?
The spiral ganglion of the cochlear nerve
Components of the vestibular labyrinth
- Saccule
- Utricle
- Semicircular ducts
The semicircular ducts arise from the…
Utricule
The semicircular ducts are concerned with…
Balance

Vestibulocochlear nerve

Vestibular ganglion

Vestibular nerve

Cochlear nerve

Sacculus

Scala tympani

Cochlear duct

Scala vestibuli

Helicotrema
2

Cochlear foramen
(with secundary tympanic membrane)
3

Ductus reuniens
4

Utriculosaccular duct
Which semicircular ducts fuse to form the common crus
- Anterior duct
- Posterior duct
What is found in the cochlear labyrinth?
The organ of corti
What is shown?

Vestibular + auditory pathway

Vestibulocochlear nerve (CN-VIII)

Vestibulocochlear nuclei

Caudal colliculus

Rostral colliculus

Acoustic area

Medial geniculate nucleus

Lateral lemniscus nucleus
Location of primary neurones concerned with the vestibular + auditory pathways
- Spiral ganglion
- Vestibular ganglion
- Cochlea
The vestibulocochlear nerve enters the…
Trapezoid body