1. The Senses

2. Vision
Photoreceptors perceive different wavelengths of light as different colors.

3. Parts of the eye Pupil- small opening that allows light into the eye
Iris – colored portion of the eye that adjusts the size of the pupil
Lens- transparent disc behind the iris that focuses light on the retina

4. Parts of the Eye
Retina – inner surface of the eye that contains photoreceptors
Rods – photoreceptors that are good at differentiating light and dark
Cones- photoreceptors that respond to different colors- don’t work well in low light levels.

5. Parts of the Eye
Optic Nerve – carries signals from the photoreceptors to the brain.
Each eye has a blind spot that is caused by the lack of photoreceptors where the nerve leaves the eye.
Cornea – Clear protective layer at the front of the eye.

6. Hearing
Sensory receptors that respond to vibrations in the air around us.

7. Parts of the Ear Auditory canal – tube that leads to the eardrum.
Eardrum- membrane that causes bones to vibrate in the ear when hit by sound waves.

8. Parts of the Ear
Auditory Ossicles – Bones in the ear that conduct sound waves from the eardrum to the cochlea.
Cochlea – portion of the ear that transfers mechanical waves into electrical nerve impulses.

9. Parts of Ear
Semi-circular canals- section of the inner ear that senses the position of the head compared to gravity
Helps keep balance.
Eustachian Tube – tube that connects inner ear to throat. Keeps fluid from building up in the ear.

10. Taste and Smell
Sensory receptors capable of differentiating between chemicals
Smell – humans can differentiate between thousands of smells.
Taste – without smell, humans can only taste four sensations – sweet, sour, bitter and salty.