Across
- 2. a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.
- 4. the transparent structure behind the pupil that changes shape to help focus images on the retina
- 5. the adjustable opening in the center of the eye through which light enters.
- 6. Retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. Cones detect fine detail and give rise to color sensations.
- 8. the nerve that carries neural impulses from the eye to the brain
- 12. the process by which the eye’s lens changes shape to focus images of near or far objects on the retina
- 13. The dimension of color that is determined by the wavelength of light, what we know as the color names blue, green, and so forth.
Down
- 1. the point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there.
- 3. the distance from the peak of one light wave or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short gamma waves to the long pulses of radio transmission.
- 6. the eye’s clear, protective outer layer, covering the pupil and iris.
- 7. the central focal point in the retina, around which the eye’s cones cluster
- 9. The amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness. Intensity is determined by the wave’s amplitude (height).
- 10. the light-sensitive part back inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information
- 11. retinal receptors that detect black, white, and gray, and are sensitive to movement. Rods are necessary for peripheral and twilight visions, when cones don’t respond.