Function of the eye

Question 1

How does the lens focus?

Answer 1

The lens changes shape; the distance between the lens and the object remains unchanged

Question 2

Emmetropia

Answer 2

The normal resting condition of the eye when the lens is flattened so that parallel rays from a distant object are focused

Question 3

What is the far point of vision?

Answer 3

It is where the lens doesn’t have to thicken to focus

It’s about 20ft from the eye

Question 4

Focal point

Answer 4

Where light rays cross and converge and cause focusing

Question 5

What are the 3 events required to bring an image closer than 7 feet to focus called?

Answer 5

1) Accommodation
2) Pupil constriction
3) Convergence

Question 6

Accommodation

Answer 6

The lens shape changes and becomes more spherical so it’s easier to see close up

Question 7

Near point of vision

Answer 7

Where the lens can no longer become more convex and close up objects become blurry

Question 8

Presbyopia

Answer 8

Increase in near point of vision as one ages. It’s why old people need reading glasses

Question 9

Pupil construction

Answer 9

Responsible for depth of focus

Question 10

Depth of focus

Answer 10

The greatest distance an object can move and still be focused

Question 11

Covnergence

Answer 11

Medial rotation of the eye (cross-eyed)

Question 12

2 Layer of the retina

Answer 12

Pigmented (anterior) and Nueronal (posterior)

Question 13

Rods

Answer 13

Photoreceptor cells for noncolor vision

Question 14

Rhodopsin

Answer 14

Purple pigment located in the discs of rods

Question 15

Opsin

Answer 15

A protein in Rhodopsin

Question 16

Renital (Vitamin A)

Answer 16

Yellow photosensitive pifment that bonds with opsin

Question 17

Where are rod cells unstiumlated?

Answer 17

In the dark

Question 18

Where are rod cells stimulated/ hyperpolarized

Answer 18

In the light

Question 19

How does rod cell hyperpolarization work

Answer 19

Na+ channels close, less Na+ enters the cells, thus glutamate released decreases and the cell is hyper polarized

Question 20

Light and dark adaptation

Answer 20

Adjustment of the eye changes in the amount of light.

It is achieved by changes in amount of available rhodopsin

Question 21

Cones

Answer 21

Responsible for color vision and visual acuity

Require bright light to work well

Question 22

Iodopsin

Answer 22

A visual pigment in cone cells

Question 23

Why can we see all the colors?

Answer 23

Even thought there are only Red, green, and blue photo pigments, their wavelengths overlap which allows us to perceive multiple colors

Question 24

Where are cones most numerous?

Answer 24

In areas of the retina associated with visual acuity, like the macula and fovea

Question 25

Where are rods?

Answer 25

The are in the remainder of the retina

Question 26

Myopia

Answer 26

Nearsightedness

Correct with a concave lens

Question 27

Hyperopia

Answer 27

Farsightedness

Correct with a convex lens

Question 28

Astigmatism

Answer 28

Cornea / lens is not uniformly curved

Question 29

Dichromatism

Answer 29

Red/green colorblindness

Question 30

2 cell types in the inner layer of the retina

Answer 30

Bipolar cells and ganglion cells

Question 31

Optic disk

Answer 31

Where teh cells of the retina converge

Question 32

Optic nerve

Answer 32

The cranial nerve leaving the eye and taking information to the visual cortex of the brain.

Question 33

Optic chiasm

Answer 33

The place in the brain, behind the pituitary cavity, where the optic nerves meet and divide into two optic tracts

Question 34

The optic tracts do what?

Answer 34

Take the information to the back of the brain to the optic radiations

Question 35

Optic radiations

Answer 35

Take visual information to the visual cortex, where the brain interperates it.

Question 36

Tunnel vision

Answer 36

Inability to detect objects in temporal half of visual field

Often a sign of a pituitary tumor

Question 37

Binocular vision

Answer 37

Where the field of vision between both eyes overlap and gives us depth perception