Across
- 3. circular sheet of muscles, contains pigment that gives eyeball colour, controls amt of light entering
- 5. tough white coat, covers the eyeball, continuous with cornea, protects the eye from chemical damage
- 7. spot region where optic nerve leaves the eye, doesn't photoreceptors
- 10. protests cornea from mechanical damage
- 11. secretes mucus to keep front of eyeball moist
- 13. the process of the lens changing thickness to focus at objects at different distances
- 15. transparent circular and biconvex structure
- 17. black pigmented middle layer, prevents internal inflection of light, contains blood vessels
- 19. innermost layer of eye wall, contains photoreceptors , connected to nerve fibres
Down
- 1. (body) contains muscles, controls thickness and curvature of lens
- 2. hole in the center of iris, allows light to enter eye
- 4. prevents excessive light from entering
- 6. red, green, blue, each time contains a different pigment, enables vairety of colours in bright light
- 7. spreads tears over the eyes for dust to be wiped off
- 8. (chamber)space behind the lens, keeps eyeball firm
- 9. stimulated even by dim light,
- 12. small yellow depression where images are focused, has cones but not rods
- 13. (chamber)space between lens and the cornea, keeps front of eyeball firm
- 14. gland secretes tears to wash away dust particles, keep cornea moist, lubricates conjunctiva
- 16. dome-shaped, transparent, refracts like rays into the eye
- 18. shields eyes from dust particles