Vision and the Structure of the Eye (Psychology 8)

The process by which the lens adjusts its shape to focus images at various distances on the retina is called __________. A. accommodation B. feature detection C. adaptation D. shape detection

A. accommodation

An image that remains after a stimulus is removed is called a(n) __________. A. afterimage B. complementary image C. dichromatic image D. trichromatic image

A. afterimage

The point where optic nerves from each eye cross over to the opposite half of the brain is the optic __________. A. chiasm B. disk C. retina D. cornea

A. chiasm

Smoking can increase someone's risk for developing __________. A. macular degeneration B. cataracts C. color vision deficiency D. blindness

A. macular degeneration

Isaac Newton discovered that __________ is a mixture of lights of many different wavelengths. A. white light B. the color white C. dark light D. the color black

A. white light

___________ of electromagnetic radiation is visible to the human eye. A. All B. A narrow portion C. The white color D. The dark color

B. A narrow portion

Specialized visual receptors that assist mostly in nighttime vision are __________. A. cones B. rods C. fovea D. optic disks

B. rods

Images that fall on the optic __________ are not visible because this area lacks rods and cones. A. chiasm B. nerve C. disk D. hole

C. disk

Optic nerves travel through the __________ to ensure that visual signals go to each hemisphere of the brain. A. optic channel B. occipital lobe C. optic chiasm D. thalamus

C. optic chiasm

According to the trichromatic theory of color vision, the eye has cones sensitive to colors associated with ___________. A. red, green, and yellow B. green, purple, and red C. red, green, and blue D. black, brown, and white

C. red, green, and blue

__________ is a result of light from distant objects falling short of the retina, causing distant objects to appear blurry. A. Farsightedness B. Macular degeneration C. Glaucoma D. Nearsightedness

D. Nearsightedness

The tough, opaque tissue that acts as the eye's protective outer layer is called the __________. A. lens B. cornea C. fovea D. sclera

D. sclera

The perception of color depends on the __________ of light an object reflects. A. function B. amplitude C. variation D. wavelength

D. wavelength

Which of the following is not a receptor pair according to the opponent process theory? A. red versus green B. yellow versus blue C. black versus white D. yellow versus red

D. yellow versus red

Trichromatic Theory

Definition A theory of color vision that states the retina has three different color receptors that assist in perception of color variation. Usage The trichromatic theory explains that the eye has three color receptors, which allow humans to see different colors.

Opponent-Process Theory

Definition A theory that states color vision results from activity in retina receptors making opposing responses to three pairs of colors. Usage The opponent-process theory helps explain some aspects of color perception not covered by the trichromatic theory.

Lens

Definition Flexible, transparent eye structure behind the iris that changes shape to help focus light rays or an image on the retina. Usage Like a camera lens, the eye's lens focuses light to form sharp, clear images.

Rods

Definition Specialized visual receptors in the retina that detect black, white, and gray and play a key role in night vision and peripheral vision. Usage The rods are very sensitive to light, so they are used to function in the dark.

Cones

Definition Specialized visual receptors located near the center of the retina that detect fine detail and play a key role in daylight vision and color vision. Usage The cones in the retina are the color-sensing cells.

Pupil

Definition The adjustable opening in the center of the eye that helps control the amount of light entering the eye. Usage When Julie stepped out of the dark theater into the bright sun, her pupils constricted, reducing the amount of light entering her eye.

Iris

Definition The colored portion of the eye that controls the size and diameter of the pupil. Usage When we say a person has blue eyes, we really mean the person has blue irises.

Retina

Definition The light-sensitive neural tissue lining the inner back surface of the eye that processes images and sends visual information to the brain. Usage The retina takes the light the eye receives and converts it into neural signals that the brain can understand.

Optic Chiasm

Definition The point at which the axons from the inside half of each eye cross over and then project to the opposite half of the brain. Usage The optic chiasm is important because it relays half the signals from each eye to each hemisphere of the brain.

True or False: Glaucoma is a group of diseases that causes damage to the retina.

False

True or False: Glaucoma is a permanent disorder and cannot be treated with surgery.

False

True or False: Subtractive color mixing involves mixing lights, as seen in theaters.

False

True or False: The color of an object is in the object itself.

False

Describe the reason why humans have a blind spot in their vision.

Humans have a blind spot because there is a hole in the retina called an optic disk, which is where the optic nerve fibers exit the eye. Humans are unable to see an image that falls within that area of the eye because it does not contain any rods or cones.

Compare and contrast the retina's two photoreceptor cells, and explain the role rhodopsin plays in vision.

Rods are highly sensitive to minimal light, allows us to see at night (shapes and movement)rhodopsin split into opsin and retinene in photon of light....opsin and retinene turn ATP into ADP and combine back to make rhodopsin. Cones are receptors for color and visual acuity (sharp vision) highest concentration in the macula lutea, and fovea centralis.

True or False: Rods play a key role in dark adaptation and detects gray, black, and white.

True

True or False: The visible spectrum of light that humans see is merely a narrow portion of the larger spectrum of electromagnetic radiation.

True

Explain how visual stimuli is relayed to the brain and how it is processed there.

The optic nerve, leading from the eyeball, allows information that we see to travel to the optic chiasm. This is the point at which axons from the inside half of each eye cross over and project to the opposite half of the brain. The purpose of the optic chiasm is to ensure that visual signals go to both hemispheres of brain. The majority of neural signals are sent to the thalamus for processing and are then distributed into areas of the occipital lobe. The neural signals are then received by the visual cortex (the ultimate destination for visual input), which is located at the occipital lobe. There, feature detectors assist us in interpreting what it is we are actually seeing as they respond to specific features of the object before us. These specific cells will fire as we encounter various shapes or movements.

Describe the trichromatic theory of color vision.

Trichromatic theory of color vision was created by Young and Helmnotz and is a theory of color vision that assumes that there are only three types of cones, each only activated by wavelength ranges of light corresponding roughly to blue, green, and red. It further assumes that all of the various colors that we can see are mixtures of various levels of activation of the three cones. If all three are equally activated, we see white. Short cones are sensitive to blue, medium cones are sensitive to green, and long cones are sensitive to red. This is due to the size wavelength the colors have. The opponent process theory was created because there are some colors we never see combined such as red and green, blue and yellow, and black and white.