Question

Vestibule is constituted by
A. Semicircular canals and utriculus
B. Sacculus and utriculus
C. Sacculus and ampullae
D. Ampullae and lagena

Answer 1

Hint: Vestibule is a part of body labyrinth. It is present medical to the eardrum. With semicircular canals, the vestibule forms a vestibular apparatus. The vestibular apparatus contains semicircular canal saccule and utricle. The main function of the vestibule is posture control and balance.

Complete answer:
The vestibule is the central part of the bony labyrinth in the inner ear. Vestibular apparatus is made up of vestibule and semicircular canals. The main function of the vestibular apparatus is to maintain posture and balance. Circular motion is handled by the 3 semicircular canals and linear motion is regulated by utricle and saccule. In a vestibular apparatus, semicircular canals contain semicircular canals and the vestibule contains utricle and saccule.

> Option A is semicircular canals and utriculus, As we already mentioned, the semicircular canal is not a part of the vestibule. It is present in a rounded bony cavity, this bony cavity is also known as a semicircular canal.

> Option B is Sacculus and utriculus, As we already mentioned, sacculus and utriculus are part of the vestibule.

> Option C is Sacculus and ampullae. Each of the three semicircular canals has at its base a bulbous expansion called the ampulla.

> Option D is Ampullae and lagena. The upper part of the ductus cochlearis is called lagana, which is not the part of the vestibule.

Hence, The correct answer is option (B).

Note: You may confuse whether an ampullae is a part of a vestibule or not. Ampullae is the expanded end of the semicircular canal that opens into the vestibule. We can say it is a part of the vestibular apparatus, but it is not a part of the vestibule. Only saccule and utricle are the part of the vestibule.