EYES

• What are sense organs composed of?

  Groups of receptor cells
• What is the primary function of the eye?

  To detect light
• What is the function of the eyelid?

  It protects the eye from dust and dirt and washes fluid over the eye when blinking.
• What is the conjunctiva?


  A thin, transparent membrane that protects the eye and keeps it moist.
• What is the role of the sclera in the eye?

  It is a tough coat that surrounds the rest of the eye in the orbit.
• What is the function of the iris?

  It contains pigments to absorb extra light and muscles to adjust the size of the pupil.
• What is the pupil?

  The gap where light enters the eye.
• How does the lens function in the eye?

  It bends and adjusts light entering the eye to focus on the retina.

  
• What is the choroid's role in the eye?

  It absorbs light after it has been through the retina and contains blood vessels to nourish the eye.
• What is the fovea?


  Part of the retina where receptors are packed most closely together.
• What does the optic nerve do?

  It carries information to the brain.
• What is the blind spot in the eye?

  Part of the retina where the optic nerve exits; there are no receptors here.
• What does the retina contain?

  Receptor cells known as rods and cones.