Introduction of hearing

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Slide 1

Topic

Sense of hearing

Slide 2

Sajida Batool

M.sc(III)

Department of Biological science KIU

Slide 3

Importance of hearing

Hearing may initially have been important to vertebrate as a mechanism to alert them to dangerous activities.

It also important in search for food and mates and in communication.

Slide 4

Cont…

Range;

Humans are not able to hear low pitched sounds, below 20 cycles per second .

Young children can hear high pitched sounds up to 20,000 cycles per second, but this ability decrease with age.

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Structure of human Ear

The human ear has three divisions…

The outer Ear

The middle Ear (eardrum)

The inner Ear

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Structure of human Ear

The outer Ear;

The outer ear consist of the

Auricle and external auditory canal.

Sound waves enter the outer ear and create pressure waves that reached the tympanic membrane.

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Structure of human Ear

The middle Ear;

The middle ear begin at the tympanic membrane and ends inside the skull.

Where two small membranous opening, the oval and round windows , are located.

Three small ossicles are between the tympanic membrane & the oval window.

Slide 8

Structure of human Ear

The middle Ear;

They include the

Malleus; (hammer)

Incus; (anvil)

Stapes;(stirrup)

So name for their shapes.

The Malleus adheres to the tympanic membrane & connect to the incus.

The incus connects to the stapes, which adheres to the oval window.

Slide 9

Structure of human Ear

The inner Ear;

The inner ear has three components.

The vestibule

semicircular canal

Cochlea

The first two, The vestibule & semicircular canals, are concerned with equilibrium.

Continuous movement of the fluid in the semicircular canal may cause motion sickness or seasickness in human

Slide 10

Structure of human Ear

The inner Ear;

Cochlea;

In mammals the long coiled sensory structure of the inner ear that contain receptor for sound is the cochlea.