Chapter 10 Study Questions

Question 1

The visual _______ is the entire area that you can see without moving your head or eyes, but the sharpness of the visual image, known as visual _______, is far greater toward the center than at the periphery. It is for this reason that we constantly shift our _______ between different objects in the environment.

Answer 1

FIELD; ACUITY; gaze

Question 2

The basic dimensions of our perception of light include , which varies through blue, green, yellow, orange, red, and intermediates; , which varies from light to dark; and , which varies from fullness to paleness. People with color blindness are impaired in the perception of : about % of males and % of females exhibit some degree of color blindness. Complete color blindness is therefore

Answer 2

HUE; BRIGHTNESS; SATURATION; HUE; 8; “5”; EXTREMELY RARE

Question 3

The apparent brightness of visual objects is subject to modification by the visual system; for example, interactions between retinal cells can enhance contrast at the boundaries of patches. The process that acts to enhance boundaries is called .

Answer 3

neighboring ;LATERAL INHIBITION

Question 4

The visual system responds to radiation. In humans, the eyes detect quanta of light energy, called , within a very narrow range of , ranging from nanometers (nm).

Answer 4

ELECTROMAGNETIC; photons; wavelengths; 400 to 700

Question 5

The blind spot is located laterally from the point of fixation for each eye and corresponds to the location at which the optic exits the eye (called the optic disc). In normal vision, the fill(s) in this perceptual gap, so the blind spot is not noticeable.

Answer 5

nerve; BRAIN

Question 6

Light travels in straight lines until it encounters the , which causes the light to bend in a process known as . As this light enters the eye, it is further modified by the , which is able to change its shape due to the muscles. This process is called and results in the projection of a sharply focused image on the , where the photoreceptors are located. The amount of light entering the eye is governed by the size of the , which may be increased by drugs (such as , or “beautiful lady”) that block transmission in the nervous system.

Answer 6

cornea; REFRACTION; lens; ciliary; accommodation; RETINA; pupil; BELLADONNA; cholinergic; PARASYMPATHETIC

Question 7

Four types of intermediate cells found in the retina, their connections, and the potentials they produce.

1. Bipolars connect to cells and produce potentials.
2. Horizontal cells connect to cells and produce potentials.
3. Amacrine cells connect to cells and cells and produce potentials.
4. Ganglion cells connect to cells and produce potentials.

Answer 7

h