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A&P Quarter 2 > Vision IV > Flashcards

Vision IV Flashcards

1
Q

What two parts make up the retina?

A

Pigmented epithelium cells

The sensory retina

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2
Q

What composes the sensory retina?

A

Photoreceptors
Bipolar cells
Ganglions

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3
Q

What are the names of the photoreceptors? Are they neurons?

A

Rods and Cones

No.

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4
Q

Only the ganglion cells produce __________ _______, the photoreceptors and _________ cells produce graded potentials.

A

Action Potentials

Ganglion

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5
Q

The are _________ million rods, and they’re in the _______ of the retina.

A

120 million

Periphery

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6
Q

What is the photopigment in rods?

A

Rhodopsin (rods= rhodopsin)

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7
Q

Rods are sensitive to _____ light

A

Low

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8
Q

Rods are _____chromatic

A

monochromatic

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9
Q

Rods mainly detect ________.

A

Movement

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10
Q

What are the three segments of a rod?

A

Outer
Inner
Cell body

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11
Q

What is in the outer segment of a rod?

A

discs arranged like stacked plates

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12
Q

What substance is rod photopigment made from?

A

Opsin

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13
Q

What is opsin?

A

a protein + retinal (pigment)

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14
Q

What is “bleaching”?

A

Opsin and retinal separate when hit with light

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15
Q

____-retinal changes to _____-retinal when light hits it, then changes back to _____-retinal

A

Cis-retinal
Trans-retinal
Cis-retinal

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16
Q

What is retinal derived from?

A

Vitamin A

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17
Q

What is retinal?

A

A pigment

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18
Q

Vitamin A is stored in the _______, and can be gained by eating ______ and ______.

A

Liver

Spinach and Carrots

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19
Q

In both rods and cones, the older discs are ________ by the ______ _______ cells

A

phagocytized

pigment epithelial

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20
Q

How many new rods are made an hour?

A

1-3

21
Q

How many cones does the eye have?

A

6 million

22
Q

Where can cones be found?

A

Centrally, in and around the fovea

23
Q

What is the pigment in cones?

A

Iodopsin

24
Q

Cones provide _____ vision and visual ______.

A

Color

acuity

25
Q

What are the three kinds of cones?

A

They all look the same: Red, Blue, Green

26
Q

Is the opsin in cones the same as opsin in rods?

A

No. The opsin in cones has a slightly different sequence of AAs than the rods’ opsin.

27
Q

Cones operate in ______ light.

A

Bright

28
Q

What causes color-blindness?

A

A lack of one kind of cone.

29
Q

What is refraction?

A

Refraction is the bending of light as it passes from one medium into another medium of a different density

30
Q

What part of the eye is responsible for refraction?

A

The cornea

31
Q

What is accommodation?

A

The process that increases the refractive power of the lens to focus up close. Or, the ability to keep focus on a nearby object as you move towards it.

32
Q

What three things must occur for accommodation to happen?

A

1- Convergence of the eyes
2- Constriction of the pupils
3- Accommodation of the lenses

33
Q

What muscle and nerve controls the convergence of the eyes?

A

Medial rectus, oculomotor nerve

34
Q

Why do the pupils constrict?

A

To focus light

35
Q

What is the far point of vision?

A

The distance beyond which no change in lens shape is needed to focusing; the lens will be flattened

36
Q

What is the near point of vision?

A

The closest point at which we can focus clearly- the maximum bulge of the lens

37
Q

Does the cornea change shape?

A

No.

38
Q

To focus, the _________ muscles relax or contract. The _______ _______ never shorten or lengthen.

A

Ciliary

Ciliary ligament

39
Q

How do we see distance?

A

The ciliary muscle relaxes (think of the eye as an egg), and as the muscle relaxes it slides back on the eyeball- this tensions the suspensory ligaments- pulling the lens into a more flattened, less convex shape. This allows for distance viewing.

40
Q

How do we see up close?

A

The muscles in the ciliary body contract, so the ciliary body slides forward on the eyeball, reducing the tension on the suspensory ligaments- allowing the lens to round up. Now, the lens is more convex, increasing focusing power.

41
Q

A normal eye is _________. Near sightedness is ________, and farsightedness is ________.

A

Emmetropic
Myopic
Hyperopic

42
Q

In a ________ eye, With this eye, light will focus correctly on the photoreceptors.

A

Emmetropic

43
Q

What kind of lens is needed to correct myopia? And does the light need to converge or diverge?

A

Concave

Converge

44
Q

In the myopic eyeball,light would focus _______ the retina. In a hyperopic eye, light would focus ______ the retina.

A

In front of

Behind

45
Q

What kind of lens is needed to correct hyperopia? And does the light need to converge or diverge?

A

Convex

Diverge

46
Q

What is astigmatism? How is it corrected?

A

Unequal curvatures of irregularities on the surface of the cornea or lens
This leads to blurry images in some areas of vision
You need special glasses or contacts to fix this

47
Q

What is strabismus?

A

Deviation of one eye which the patient cannot overcome

Aka, cross-eyed, lazy eyed

48
Q

What is neural convergence?

A

Rods participate in converging pathways (100 rods per ganglion)
So rod effects are considered collectively, resulting in fuzzy vision

49
Q

The optic nerves become the optic _______ after crossing at the optic ______.

A

Tract

Chiasm

A&P Quarter 2 (16 decks)

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