Mastering bio_Vision

hyperopia

A condition in which visual images come to a focus behind the retina of the eye and vision is better for distant than for near objects -- called also farsightedness.

fovea centralis

A student is staring directly at a bird outside the classroom window. The image of the bird is focused at the very center of the macula, a small pit called the ________, which is lined with highly packed photoreceptors.

impaired color vision.

An insufficient number of particular types of cones causes

stiffening of the lens and loss of accommodation capability

As humans age, their ability to focus on nearby objects deteriorates. This is the result of

cones

Color blindness usually results from a decrease in the number of

hyperopia

Convex lenses can correct ________, also called farsightedness.

rhodopsin

Dim light causes the pigment ________ in rods to change shape, which causes sodium channels on the photoreceptor cell to close and activate ganglion cells.

glaucoma

During eye examinations, a test is done to monitor the pressure within the eye. This test is done to detect

Cones are evenly distributed throughout the retina, accounting for visual acuity.

Each of the following statements about cones is TRUE, EXCEPT which one?

changing the shape of the cornea

LASIK treatment functions to improve eyesight by

length of the eyeball

Nearsightedness and farsightedness are caused by the

the photopigment found in rods

Rhodopsin is __________.

True

T/F Both eyes have an optic disk. When an image is focused on the optic disk, it cannot be "seen."

False

T/F LASIK surgery involves removing the cornea and reshaping the lens to correct for vision problems such as nearsightedness, farsightedness, and astigmatism.

optic disk

The "blind spot" is associated with which one of the following?

3, 4, 2, 1, 5

The following is a list of structures in the eye through which light passes. Which one of the following answers best describes the order in which light passes through or hits each structure? 1. lens 2. pupil 3. cornea 4. aqueous humor 5. retina

where the optic nerve exits the eye - The optic disc is a "blind spot," where the nerves and blood vessels exit the eye.

The optic disc is the area of the eye __________.

rods and cones

The photoreceptors of the eye are __________.

cornea

The transparent covering of the front of the eye is the

Retina

The vitreous humor fills the main chamber of the eye. Which one of the following structures of the eye would vitreous humor come in direct contact with?

retinal detachment

This phenomenon, which is a medical emergency, involves the peeling of the retina away from the choroid.

rod

Vision in dim light is due to the activity of ________ cells because their rhodopsin pigment is much more sensitive to light than other photopigments.

Cones are more highly concentrated in the fovea centralis.

Which of the following correctly describes the distribution of rods and cones in the retina?

cornea—aqueous humor—pupil—lens—vitreous humor—retina

Which of the following correctly traces the path of light through the eye?

Many rods converge on a single ganglion.

Which of the following statements explains why vision is less sharp in dim light than in bright light?

the iris

Which of the following will regulate the amount of light entering the eye?

cataracts

Which one of the following conditions results when the transparency of the lens decreases?

The pupil decreases in size

Which one of the following occurs when bright light hits the eye?

sclera

Which one of the following parts of the eye is continuous with the cornea and forms the outer surface of the back of the eye?

Myopia is fixed by

concave lens

Hyperopia is fixed with

convex lens

myopia

nearsighted