1. What are your five major senses?

2. Special Senses: Vision

3. External Structures of Eye Eye lids Eye lids Eyelashes Eyelashes Conjunctiva-thin membrane under eyelid Conjunctiva-thin membrane under eyelid

4. Tear Glands Lacrimal glands produce tears Lacrimal glands produce tears Tears are dilute salt solution Tears are dilute salt solution Contain lysozyme to kill bacteria Contain lysozyme to kill bacteria Drain into nasal cavity Drain into nasal cavity

5. Structures of Eye Sclera- “white of eyes”;thick layer that protects eye Sclera- “white of eyes”;thick layer that protects eye Cornea- clear medial window in sclera;allows light into eye Cornea- clear medial window in sclera;allows light into eye Choroid – dark internal layer of eye; keeps light from scattering in eye, keeps inside of eye dark. Choroid – dark internal layer of eye; keeps light from scattering in eye, keeps inside of eye dark.

6. Ciliary body - holds lens Ciliary body - holds lens Lens – bends to focus light on correct part of retina Lens – bends to focus light on correct part of retina Iris- pigmented; contains hole called pupil which allows light through Iris- pigmented; contains hole called pupil which allows light through

7. So how do you actually see? Retina – receives and translates light message into nerve impulses Retina – receives and translates light message into nerve impulses Contains photoreceptors called rods and cones Contains photoreceptors called rods and cones Messages leave photoreceptors and pass to optic nerve, then to occipital lobe of brain for translation. Messages leave photoreceptors and pass to optic nerve, then to occipital lobe of brain for translation. Fovea Centralis- Region of the retina that produces the sharpest vision. Fovea Centralis- Region of the retina that produces the sharpest vision.

8. Blind Spot Optic nerve is covered by photoreceptors Optic nerve is covered by photoreceptors Except for optic disc (where optic nerve leaves eyeball) Except for optic disc (where optic nerve leaves eyeball) Blind spot Blind spot