Biology Eye and Ear ppt

Unit 12 - Human Systems

EYE & EAR

The Ear
• Functions in hearing and balance
• Outer ear- consists of pinna and
auditory canal
– They connect sounds waves to
eardrum
• Eustachian tube- connects middle ear
to pharynx
• Inner ear- contains semicircular canals
and cochlea- contain of fluid- help
determine balance

Ear Overview

The middle and inner ear

The Eye
• Pupil- light enters
• Iris- changes pupil’s diameter to
control light entry
• Lens- focuses light into the retina
• Retina – consists of photoreceptor cells
• Sclera- whites of eyes
• Cornea- let’s light in and focuses light
• Optic nerve- transmits visual input
from retina to brain

The Eye

Photoreceptors
• Found at etches of retina
• Cones- are stimulated by bright light
and can distinguish color
• Rods- extremely light sensitive..
Help with night vision