the eye

• what is the supporting wall of the eye?

  the sclera
• what is the transparent outer layer at the front of the eye?

  the cornea
• what does the cornea do?

  refracts light into the eye
• what does the iris do? how?

  controlls how much light enters the eye, using muscles that allow it to controll the pupil size
• what does the lense do?

  focuses the light on the retina
• what contains receptor cells sensitive to light intensity and colour?

  the retina
• what controlls the shape of the lense?

  the ciliary muscles and suspensory ligaments
• what does the optic nerve do?

  carries impulses from the receptors (on the retina) to the brain
• lable the parts of the eye:

  A) supensory ligaments

  B) pupil

  C) sclera

  D) cornea

  E) iris

  F) optic nerve

  G) ciliary muscles

  H) retina

  I) lense

  
• how does the eye respond to bright light?

  light receptors detect light, so a reflex is triggered to make the pupil smaller. the circular muscles in the iris contract and the radial muscles relax, reducing the amount of light that can enter the eye
• how does the eye respond to dim light?

  light receptors detect dim light, so a reflex is triggered to make the pupil wider. the radial muscles in the iris contract and the circular muscles relax, increasing the amount of light that can enter the eye.
• what is accommodation?

  the eye focusing light on the retina by changing the shape of the lense
• what happens when you look at near objects?

  the ciliary mucles contract, which slackens the suspensory ligaments, the lense becomes fat, which increases the amount that it refracts light
• what happens when you look at far objects?

  the ciliary mucles relax, which allows the suspensory ligaments to tighten, the lense becomes thin, which decreases the amount that it refracts light