Cochlea Flashcards

Explore the cochlea's spiral structure, fluid compartments, organ of Corti, sensory hair cells, innervation, blood supply, and hearing mechanisms.

Card 1 of 30Question

What is the cochlea?

A spiral-shaped structure of the inner ear containing the sensory apparatus for hearing.

In This Section

1. What is the cochlea?

A spiral-shaped structure of the inner ear containing the sensory apparatus for hearing.

2. Where is the cochlea located?

Within the petrous part of the temporal bone, anterior to the vestibule of the inner ear.

3. How many turns does the human cochlea typically make?

Approximately two and a half turns around its central axis.

4. What is the modiolus of the cochlea?

The central bony core around which the cochlear spiral winds.

5. What is the osseous spiral lamina?

A thin bony shelf projecting from the modiolus that supports the medial attachment of the basilar membrane.

6. What are the three fluid-filled compartments of the cochlea?

The scala vestibuli, scala media, and scala tympani.

7. Which cochlear compartment contains the membranous cochlear duct?

The scala media.

8. Which fluid fills the scala media?

Endolymph, which is rich in potassium ions.

9. Which fluid fills the scala vestibuli and scala tympani?

Perilymph, which has a relatively high sodium concentration.

10. Which membrane separates the scala vestibuli from the scala media?

The vestibular membrane, also called Reissner's membrane.

11. Which membrane separates the scala media from the scala tympani?

The basilar membrane.

12. What is the helicotrema?

An opening at the cochlear apex connecting the scala vestibuli and scala tympani.

13. Which cochlear compartment receives pressure waves from the stapes at the oval window?

The scala vestibuli.

14. Which cochlear compartment terminates at the round window?

The scala tympani.

15. What is the organ of Corti?

The sensory epithelium for hearing, located on the basilar membrane within the cochlear duct.

16. What are the two major types of sensory hair cells in the organ of Corti?

Inner hair cells and outer hair cells.

17. How are inner and outer hair cells typically arranged?

Inner hair cells form one row, while outer hair cells typically form three rows.

18. What is the primary function of inner hair cells?

They convert mechanical vibrations into neural signals carried by auditory nerve fibers.

19. What is the primary function of outer hair cells?

They actively amplify and sharpen cochlear mechanical responses through electromotility.

20. What are stereocilia on cochlear hair cells?

Actin-rich projections that deflect in response to sound-induced mechanical movement.

21. What is the tectorial membrane?

A gelatinous extracellular structure overlying the organ of Corti and interacting with hair cell stereocilia.

22. What is the stria vascularis?

A specialized vascular epithelium on the lateral cochlear duct wall that produces potassium-rich endolymph and maintains the endocochlear potential.

23. Where are the cell bodies of primary auditory sensory neurons located?

In the spiral ganglion within the modiolus.

24. Which cranial nerve carries sensory information from the cochlea?

The cochlear division of the vestibulocochlear nerve (cranial nerve VIII).

25. Where do cochlear nerve fibers first synapse in the central auditory pathway?

In the dorsal and ventral cochlear nuclei at the pontomedullary junction.

26. Which artery primarily supplies the cochlea?

The cochlear branches of the labyrinthine artery, usually arising from the anterior inferior cerebellar artery.

27. Which region of the basilar membrane responds most strongly to high-frequency sounds?

The narrow, stiff basal region near the oval window.

28. Which region of the basilar membrane responds most strongly to low-frequency sounds?

The wider, more flexible apical region near the helicotrema.

29. What is cochlear tonotopy?

The orderly mapping of sound frequencies along the cochlea, from high frequencies at the base to low frequencies at the apex.

30. Why can damage to cochlear hair cells cause permanent sensorineural hearing loss?

Mature human cochlear hair cells have little capacity for spontaneous regeneration after injury.