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1.5 SENSE OF HEARING

-The ear is the sensory organ for hearing

and body balance.- the ear has 3 main parts: outer ear, middle

ear and inner ear.

PART OF

EAR

FUNCTION

Outer ear Receives and directs sound waves to

the eardrum

Middle ear Vibrates and transmit sound vibrationsto the inner ear

Inner ear Convert sound vibration into nerve

impulses which are carried by auditorynerve to the brain.

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Outer ear Middle ear Inner ear

ear pinna

ear canal

eardrum

Ossicles

Semicircularcanal

Cochlea

Eustachian

tube

Auditorynerve

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Part of the ear Function

(c) Inner ear

Function:

Convert sound

vibration into

nerve impulses

which are

carried by

auditory nerve

to the brain.

(l) Cochlea Changes sound vibrations to nerve

impulse(k) Auditory

nerves

Sends nerve impulse to the brain for

interpretation

Doesnt involvein hearing

mechanisms

(l) Eustachiantube

Equalizes the air pressure in bothsides of the ear

(m)Semicircular

canal

Controls the balance of body

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The flow chart of hearing mechanism.

Ear pinna Ear canal eardrum

ossiclesoval windowcochlea

Auditory nerve Brain

Nerve impulse

Nerve

impulse

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1.6 sense of sight

Aqueous humour

Cornea

Pupil

Iris

Lens

Ciliary muscles

Vitreous humour

Sclera

Choroid

Retina

Yellow spot

Blind spot

Nerve

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Part of the

eye

Function

Aqeoushumuor

Maintains shape of eyeball. Helps to focuslight onto retina.

Sclera Protect eyeball.

Choroid Absorbs light to prevent reflection.Lens Focus light onto retina

Vitreous

humour

Maintains shape of eyeball. Helps to focus

light onto retina.

Retina Detects image forms

Iris Control size of pupil

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Part of the eye Function

Cornea Helps to focus light onto retina

Ciliary

muscles

Contracts and relaxes to changes the

thickness of the lens.

Pupil Allows light to enter the eyesConjuctiva Protects the cornea

Yellow spot Detects light or image and form nerve

impulseBlind spot The part of the eye that are not sensitive to

light.

Optic nerve Carries nerve impulses from the retina to the

brain for intepretation.

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The flow chart of mechanism of sight.

LIGHT Cornea Aqueous

humour

PupilLensVitreous humour

Retina Optic nerveNerve

impulse

Brain

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1. http://www.youtube.com/watch?v=tkPj4IGbmQQ2. http://www.youtube.com/watch?v=0HzWmldLDHI&feature=watch_response

http://www.youtube.com/watch?v=tkPj4IGbmQQhttp://www.youtube.com/watch?v=0HzWmldLDHI&feature=watch_responsehttp://www.youtube.com/watch?v=0HzWmldLDHI&feature=watch_responsehttp://www.youtube.com/watch?v=tkPj4IGbmQQ

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Iris control the size of pupil in order to allow certain

amount of light to enter our eyes.

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1.7 LIGHT AND SIGHT

Reflection: light bounces off the surface of an

object.

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Law of Reflection isobeyed if the parallel

light rays fall ontouniform surface.

If the light rays fallonto non uniform

surface, the reflectedray will be dispersed.

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Application of reflection of light.

Periscope

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1.7 LIGHT AND SIGHT

Refraction : happen when light

travels through two

different medium

with different

densities at an

angle. This cause

the light to bent.

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