The document describes the layers of the eyeball, which are the fibrous tunic, vascular tunic, and retina. It then discusses the interior of the eyeball, including the lens, ciliary muscle, anterior and vitreous chambers. Finally, it covers the two types of photoreceptors - rods and cones - and their different functions in vision.

1. Visual Sense (pg 10)

2. Layers of the eyeball

3. Layers of the eyeball
• Fibrous tunic: Outer coat. Consists of cornea
(clear) and sclera (white)

4. Layers of the eyeball
• Fibrous tunic: Outer coat. Consists of cornea
(clear) and sclera (white)
• Vascular tunic: Middle layer. Contains many
blood vessels. Consists of choroid (dark brown
layer that absorbs excess light) and iris
(colored part of the eye. Doughnut shaped.
Has muscles that constrict or dilate the iris to
change the size of the pupil)

5. Layers of the eyeball
• Fibrous tunic: Outer coat. Consists of cornea
(clear) and sclera (white)
• Vascular tunic: Middle layer. Contains many
blood vessels. Consists of choroid (dark brown
layer that absorbs excess light) and iris
(colored part of the eye. Doughnut shaped.
Has muscles that constrict or dilate the iris to
change the size of the pupil)
• Retina: Inner layer. Lines the posterior ¾ of
the eyeball. Contains photoreceptors

6. Interior of the Eyeball
• Lens: transparent, convex structure that
focuses light onto the retina

7. Interior of the Eyeball
• Lens: transparent, convex structure that
focuses light onto the retina
• Ciliary muscle: Alters the shape of the lens for
viewing objects up close or at a distance

8. Interior of the Eyeball
• Lens: transparent, convex structure that
focuses light onto the retina
• Ciliary muscle: Alters the shape of the lens for
viewing objects up close or at a distance
• Anterior cavity: space anterior to the lens.
Filled with aqueous humor (watery)

9. Interior of the Eyeball
• Lens: transparent, convex structure that
focuses light onto the retina
• Ciliary muscle: Alters the shape of the lens for
viewing objects up close or at a distance
• Anterior cavity: space anterior to the lens.
Filled with aqueous humor (watery)
• Vitreous chamber: large cavity behind the
lens. Filled with vitreous humor (jelly-like)

10. Photoreceptors
• Rods: 120 million. Sensitive to dim light. Only
see black and white. Most abundant at edges
of retina

11. Photoreceptors
• Rods: 120 million. Sensitive to dim light. Only
see black and white. Most abundant at edges
of retina.
• Cones: 6 million. 3 types: blue, green, and red.
Stimulated by brighter light. Allows color
vision. Most abundant at the fovea centralis, a
point at the center of the retina where images
are sharpest

12. Pop Quiz!
• Hold up “rod” or “cone” sign

13. Pop Quiz!
1. Responsible for peripheral vision

14. Pop Quiz!
1. Responsible for peripheral
vision
RODS

15. Pop Quiz!
2. Used in moonlight

16. Pop Quiz!
2. Used in moonlight
RODS

17. Pop Quiz!
3. Missing in color-blind people

18. Pop Quiz!
3. Missing in color-blind people
CONES

19. Pop Quiz!
4. If these are damaged you should
not drive at night

20. Pop Quiz!
4. If these are damaged you should
not drive at night
RODS

21. Pop Quiz!
5. Allows you to see fine detail

22. Pop Quiz!
5. Allows you to see fine detail
CONES