Mod 18 Reading Guide

Match the following

• Wavelength

• the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude

• amplitude

• determines wavelength...a high one = a short wavelength. A low one = a long wavelength

• hue

• determines a wave's intensity, or height. A small one = dull colors. A great one = bright colors.

• Intensity

• The distance between two corresponding parts of a wave

• frequency

• the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth

Match the following

• Iris

• 
  the transparent structure behind the pupil that changes shape to help focus images on the retina

• cornea

• The clear tissue that covers the front of the eye

• Pupil

• a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

• lens

• the adjustable opening in the center of the eye through which light enters

• retina

• the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information

the process by which the eye's lens changes shape to focus near or far objects on the retina

...optics expert Johannes Kepler showed that the retina ​ (a)   receive ​ (b)   images of the world. So how could we understand such a world? "I leave it," said the befuddled Kepler, "to natural philosophers." Today's answer: The retina ​ (c)   "see" a whole image. Rather, its millions of ​ (d)   convert particles of light energy into neural impulses and forward those to the brain, which reassembles them into what we perceive as an ​ (e)   image.

• does
• upside-down
• doesn't
• receptor cells
• upright-seeming
• brain cells
• might

Match the following

• blind spot

• the nerve that carries neural impulses from the eye to the brain

• optic nerve

• retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond

• rods

• the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there

• cones

• the central focal point in the retina, around which the eye's cones cluster

• fovea

• retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.

Rods and cones are our eyes' light-sensitive

Which apply to Rods?

• 120 Million

• High sensitivity to dim light

• High sensitivity to detail

• low sensitivity to color

• located in the center of the retina

Which apply to Cones?

• 120 Million

• High sensitivity to dim light

• High sensitivity to detail

• high sensitivity to color

• located in the center of the retina

Match the following

• feature detectors

• the theory that the retina contains three different color receptors—one most sensitive to red, one to green, one to blue—which, when stimulated in combination, can produce the perception of any color.

• opponent-process theory

• nerve cells in the brain's visual cortex that respond to specific features of the stimulus, such as shape, angle, or movement

• Young-Helmholtz trichromatic theory

• the theory that opposing retinal processes enable color vision

• parallel processing

• the processing of many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision.

• blindsight

• a condition in which a person can respond to a visual stimulus without consciously experiencing it

According to page 181, dogs lack receptors for wavelengths of red, giving them only limited ____________ color vision