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Physiology of hearing and hearing loss

Question
13 out of 39
 

Angular movements are sensed by: (LQ)



A Cochlea

B Saccule

C Utricle

D Semicircular canals

Ans. D Semicircular canals

Semicircular canals/ducts

Cristae

Located in the ampullated end of the semicircular ducts

Angular/Rotational acceleration and deceleration

17.jpg

It is a crest-like mound of connective tissue on which the sensory epithelial cells lie.

Cells are of 2 types, Type, I (flask-shaped)

Type II (cyclindrical)

From the uppe surface of each cell projects a single hair

k/a krnociliurn.

When movement of the endolymph occurs toward

kinocilium discharge increases, and when it occurs away

from kinocilium discharge decreases

This stimulates sensory nerve endings which sends

impulses upward to the brain giving information about the movement of head

Peripheral receptors

Respond to

Structure

Utricle and sacule (otolith organ)

Macula

Linear acceleration/gravity!change in position of head

18.jpg

It has 2 parts

• A sensory neuroepithelium made ofType I and Type II cells

(similar to crista)

• An otolithic membrane which is made of gelatinous mass and

on the top has crystals of calcium carbonate called as otolith."

The cilia of the hair cells project into the gelatinous layer

The linear, gravitation and head tilt movement causes displacement

of the otolithic membrane and thus stimulate the hair cells which

lie in different planes.

Extra edge

Between the ultricle and saccule:

Utricle

Saccule

Utricle + saccule

Senses horizontal linear acceleration

Senses vertical linear acceleration

Both sense gravity and position of head in space

Coriolis effect - It is a specific type of angular acceleration (. sensed by semicircular ducts) that causes motion sickness in space craft due to rotation of earth.

Type I cells correspond to the inner hair cells of organ of Corti and Type II cells correspond to the outer hair cells.

Physiology of hearing and hearing loss Flashcard List

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