1. Special Senses: Vision  Overview of Special Senses  Anatomy of the Eye External Anatomy Internal Anatomy  Photoreception  Lens Anatomy  Refraction of Incoming Light  Transmission of Visual Information  Visual Reflexes

2. The Senses  General senses of touch Temperature Pressure Pain  Special senses Smell Taste Sight Hearing Equilibrium

3. Accessory Structures of the Eye

5.  Lacrimal apparatus Lacrimal gland – produces lacrimal fluid Lacrimal canals – drains lacrimal fluid from eyes Figure 8.1a

6. Extrinsic Eye Muscles Figure 8.2

7. Three Tunics: Sclera/Cornea, Choroid, Sensory Figure 8.3a

8. Neurons of the Retina (Sensory Tunic) Figure 8.4

9. Retinal Anatomy

10. Cone Sensitivity  There are three types of cones  Different cones are sensitive to different wavelengths  Color blindness is the result of lack of one cone type Figure 8.6 Cones “see” in color Rods “see” in shades of gray

11. Lens and Humors Figure 8.3a

12. Lens Accommodation Figure 8.9  Light must be focused to a point on the retina for optimal vision  The eye is set for distance vision (over 20 ft away)  The lens must change shape to focus for closer objects  Lens flattened (ciliary muscle relaxation) for distance vision  Lens bulges (ciliary muscle contraction) for close-up vision

13. Problems in Lens Accommodation: Nearsighted and Farsightedness

14. Cow Eye aqueous humor Optic nerve Blind spot/optic disc

15. Images Formed on the Retina are Upside Down Figure 8.10

16. Visual Pathway Figure 8.11

17. Eye Reflexes  Internal muscles are controlled by the autonomic nervous system Bright light causes pupils to constrict through action of radial and ciliary muscles Viewing close objects causes accommodation  External muscles control eye movement to follow objects  Viewing close objects causes convergence (eyes moving medially)

18. Special Senses: Vision  Overview of Special Senses  Anatomy of the Eye External Anatomy Internal Anatomy  Photoreception  Lens Anatomy  Refraction of Incoming Light  Transmission of Visual Information  Visual Reflexes