S 1.3

Question 1

• It is a spiral canal shaped like a snail shell, is embedded in temporal bone.
• It forms 2 3/4 turns from base to apex, is 30- 35 mm long, and has a lumen with three compartments: scala media (cochlear duct), scala vestibuli, and scala tympani

Answer 1

EAR: Cochlea

Question 2

EAR: Cochlea:
- It forms 2 3/4 turns from base to apex, is 30- 35 mm long, and has a lumen with three compartments: scala _____ (cochlear duct), scala _______, and scala ________

Answer 2

media; vestibuli; tympani

Question 3

EAR: Cochlea:
This is filled with endolymph; perilymph fills the other two scalae

Answer 3

cochlear duct

Question 4

EAR: Cochlea: Cochlear duct: What compartments?
The scalae ________ and __________ communicate through the helicotrema, a small opening at the cochlear apex

Answer 4

vestibuli; tympani

Question 5

EAR: Cochlea: Cochlear duct:
The scalae vestibuli and tympani communicate through the _________, a small opening at the cochlear apex

Answer 5

helicotrema

Question 6

EAR: Cochlea:
- It is a triangular space in transverse section.
- Its lateral border makes up the stria vascularis—a richly vascularized pseudostratified epithelium that secretes endolymph

Answer 6

Cochlear duct

Question 7

EAR: Cochlea: Cochlear duct:
Its lateral border makes up the stria vascularis—a richly vascularized pseudostratified epithelium that secretes __________

Answer 7

endolymph

Question 8

EAR: Cochlea:
This marks the roof of the cochlear duct, consists of two layers of simple squamous epithelium and delineates cochlear duct from scala vestibuli.

Answer 8

Reissner’s (vestibular) membrane

Question 9

EAR: Cochlea:
- A thicker ___________ membrane forms the floor of the cochlear duct and separates it from scala tympani.
- Superimposed on this membrane is highly specialized epithelium—the organ of Corti—that consists of hair cells and supporting cells.

Answer 9

basilar

Question 10

EAR: Cochlea:
These are specialized auditory receptor cells. They have apical stereocilia whose tips are embedded in the gelatinous tectorial membrane.

Answer 10

Cochlear hair cells

Question 11

EAR: Cochlea:
Arising from the base of the ______ _____ _______ are afferent nerve fibers that synapse with bases of hair cells.

Answer 11

organ of Corti