1. Eyes and Vision
Deprtment of Biology, WCU

2. Introduction 70% of all sensory receptors Large optic tracts
1/6 exposed
5/6 covered

3. Structure of the eyeball
Poles
Tunics (covering)
Humor (fluid)
Segments

4. Fibrous tunic Dense, avascular CT
Sclera (opaque), cornea (transparent)
Functions
protects, shapes, muscle anchor
light entry

5. Vascular tunic (uvea) 1. Choroid 2. Ciliary body
5/6th of tunic, nutrients
2. Ciliary body
smooth muscle
suspensory ligaments

6. Vascular tunic
3. Iris
colored portion
pupil regulates light level

7. Sensory tunic (retina)
Pigmented cells absorb light
Ora serrata

8. Retina 1. Photoreceptors 2. Bipolar cells 3. Ganglion cells
Rods and cones
2. Bipolar cells
3. Ganglion cells

9. Light pathway
Blind spot

10. Eye structure Posterior segment vitreous humor Functions
transmits light
holds retina
counteract muscle force

11. Eye structure Anterior segment Anterior and posterior chambers
aqueous humor
ciliary process, canal of Schlemm
Functions
support
nutrients and oxygen
metabolic waste
cleans eye

12. Accessory structures 1. Eyebrows 2. Eyelids (palpebrae)
shade from sunlight
prevent trickling perspiration
2. Eyelids (palpebrae)
palpedral fissure
canthi
caruncle (sweat glands)

13. Eyelid movement Orbicularis oculi Levator palpebrae superioris
Functions
protect eye
prevent dessication
spread oil, mucus, saline
Eyelashes

14. Glands 1. Tarsal gland 2. Conjunctiva
oily secretion, prevents adhesion
2. Conjunctiva
mucus, lubricates, prevent desiccation

15. Glands 3. Lacrimal location saline (nasal cavity)
mucus, antibodies lysozyme

16. Physiology of vision Light travels in waves
Color (i.e. red object reflects red light)
Light entering eye is refracted
Image is inverted and backward

17. Physiology of vision
Focusing (lens shape change)

18. Physiology of vision
Myopia
Hyperopia