The Eye Flashcards

1
Q

What is the aqueous humour?

A

A fluid found behind the cornea
Maintained by lymphatic system
Provides nutrients to the cornea
Helps focus light into eye

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2
Q

What is the vitreous humour

A

Jelly like fluid
Fills up the eye
Involves in focussing

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3
Q

What is a conjunctiva

A

A curve under the eyelid which prevents dirt from getting to the back of your eye

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4
Q

Where is the blind spot?

A

A part of your eye in the back where no neurons or light are present

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5
Q

What is the cornea

A

Clear
Glass-like tissue
A specialized part of the sclera
Helps focus your vision by refracting light
Made of living cells
No blood vessels but gets oxygen from air surrounding it and releases CO2

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6
Q

What is the sclera

A
White of the eye
Tough and rubbery
Protection
Maintains shape of eye
Sites for muscle attachment
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7
Q

What is the retina?

A

Very thin
Responsible for detecting light
Contains photoreceptors

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8
Q

What is the choroid?

A

Absorbs all light that is not absorbed by retinal layer - why pupil is black

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9
Q

What is the iris?

A

Controls the amount of light that comes into the eye

Contains a sphincter

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10
Q

What are the purpose for the ciliary body and ciliary ligaments?

A

To focus light into the eye

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11
Q

What is a lens

A

Living cells
Very low metabolism
Rubbery - can change shape

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12
Q

What happens when light passes through a substance?

A

It refracts

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13
Q

How does a substance effect refraction?

A

The thicker the substance the more it refracts?

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14
Q

When objects are close to the eye, we have to bend the light _______.

A

More

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15
Q

In order to reflect the light more we have to make the lens ________.

A

Thicker

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16
Q

If the ciliary muscle is contracted, it will ________ the tension on the ligaments and the lens gets _________.

For close objects

A

Decrease

Thicker

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17
Q

If the ciliary muscle is dial aged, the ligaments ______ and the lens gets ________.

For far objects

A

Tighten

Thinner

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18
Q

What is accanodation

A

Focus plus light adjustment

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19
Q

What neurons (cells) do the photoreceptors send their signal to?

A

Photoreceptors -> bipolar cells -> ganglion cells

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20
Q

What are the 2 types of photoreceptors?

A

Ross and cones

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21
Q

What pigment is in rods and cones?

A

Rhodopsin

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22
Q

What is rhodopsin is broken down into?

A

Retinal (retinine - vitamin A)

Opsin (protein)

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23
Q

Types of opsin?

A

Regular
Short
Medium
Long

24
Q

What differs in the types of opsin?

A

React with different wavelengths of light

25
Q

What is special about the regular opsin?

A

Reacts with all wavelengths of light

26
Q

How is rhodopsin formed?

A

An enzyme puts the Belen down parts (retinal and opsin) back together

Takes about 2 hours

27
Q

What does retinal do?

A

When present Na channels open creating an action potential.

28
Q

What opsin do Ross contain?

A

Regular
React with all wavelengths
Black and white vision

29
Q

Are rods extremely light sensitive?

A

Yes

30
Q

What are rods responsible for?

A

Night vision

All is us to see in low light conditions

31
Q

Where are rods mostly found?

A

Peripheral vision around the outside of the eye

32
Q

Where do rods send their signals to?

A

The occipital lobe

33
Q

What type of motion do rods see?

A

Organic motion

Moving, loving things

34
Q

What are rods good at detecting in bright lights

A

Edges and shadows

35
Q

What do rods share that causes low resolution?

A

Bipolar cells

36
Q

What is another word for resolution?

A

Aquity

37
Q

There are three types of cones containing different types of opsin. These are?

A

Short - blue
Medium - green
Long - short

Each one reacts with a different section of the light spectrum

38
Q

How many wavelengths does one cone react with?

A

One wavelength.

39
Q

Are cones light sensitive?

A

Not as much as rods

40
Q

What are the primary colours of light?

A

Green
Red
Blue

41
Q

Rods don’t share these, causing them to have a high resolution

A

Bipolar cells

42
Q

Where are cones located?

A

Packed in the centre

43
Q

What is the fovea centralis?

A

Centre focus area
Packed with cones
Best vision

44
Q

What is the blind spot?

A

No vision

No rods or cones

45
Q

What is binocular vision?

A

Two eyes - each seeing a different image and the brain combines them into one

46
Q

What is the optic chiasma?

A

Cross of the optic nerves

47
Q

How many sides does the retinal later on each eye have?

A

Two sides

48
Q

How do we have depth perception?

A

We rely on visual cues.

49
Q

Name the four visual cues

A
Motion parallax
Converging lines
Overlay
Relative size
Shadows/Textiles/Gradients
50
Q

What is motion parallax?

A

Objects further away appear to move slower through your field of view

51
Q

What are converting lines

A

Corners that tell us what is close and far

52
Q

What is overlay

A

One thing is obscuring another thing

Ex. Buildings in front of each other

53
Q

What is relative size?

A

Objects that are small are generally farther away

54
Q

What do Shadows/Textiles/Gradients tell us about depth?

A

Lose texture when something is further away

55
Q

What causes a negative afterimage?

A

Fatiguing a specific cone

Can no longer see that wavelength of light

56
Q

What causes a positive after image?

A

Over stimulation of rods and cones

Ex. A camera flash

57
Q

What are the three layers of the eye?

A

Sclera
Choroid
Retina