Vision - Eye and Retina Flashcards Preview

Physiology 2130 > Vision - Eye and Retina > Flashcards

Flashcards in Vision - Eye and Retina Deck (36):
1

Which range of vision is the human eye sensitive to

The visible range 400-700nm

2

Examples of long vs short wavelength

Long: Radiowaves
Short: Gamma Rays

3

Where is the visual cortex

Occipital Lobe

4

What is the visual path

Eye>Optic Nerve> Optic Chiasm>Optic Tract>Lateral Geniculate body(Thalamus)>Primary visual cortex

5

What are the retinal targets

1. Lateral geniculate nucleus (thalamus)
2. Superior colliculous
3.Pretecum-Edinger Westphal nucleus
4. Hypothalamus

6

What is the definition of visual acuity

The capacity of the visual system to resolve fine spatial detail

7

What are the 3 factors of visual acuity

1. Stimulus
2. Eye
3. Central visual pathways

8

What is Snellen acuity

When you view the letter chart at 20ft

9

What is 20/20 vision

at 20ft a viewer can detect 1 degree critical features

10

What is lower visual actuity

at 20ft, you can see like normal people at 40ft. (20/40)

11

What is higher visual acuity

at 20ft you can see like normal people at 15ft (20/15)

12

What does it mean to be legally blind

When a persons best corrected vision is 20/200 or worse

13

What is the sclera

The white part of the eye (90%)

14

What is the orbit?

The boney captivity that protects the orbit

15

What is the cornea

A clear sheet in front of the pupil and iris

16

What is the conjunctiva

Little space inside of the eyelid

17

What is the lens

The inside of the pupil. the disk being pulled in and out of focus by the zone fibers and ciliary muscles

18

What is the Aqueous Humor of the eye

It is between the cornea and the lens

19

What is the Vitreous Humor of the eye

Between the lens and the retina

20

What is the retina

A wall of photoreceptors at the back of the eye

21

What is the fovea

A spot in the retina where there are no rod cells

22

What are the 5 cell types of the retina

1. Ganglion
2. Amacrine
3. Bipolar
4. Horizontal
5. Photoreceptors

23

What are the 2 retinal layers

1. Nuclear layer - Where the cell bodies are
2. Plexiform layer - where the synapse and axons are

24

What is the order of the retinal layers?

Ganglion cell layer
Inner plexiform layer
Inner nuclear layer
Outer plexiform layer
Outer nuclear layer
Photoreceptor outer segments

25

How many layers of cells lines the back of the retina

3

26

What lines the back of the retinal wall

The epithelium wall is after the photoreceptors and is black

27

What are the 2 main parts of a photoreceptor

Outer segment - photosensitive part
inner segment - contains the cell body

28

What are the 2 types of photoreceptors

Rod and cone

29

What are cone cells

Colour sensitive
Used during daylight conditions
5 million in each retina
Fovea only consists of cones

30

What are rod cells

Light sensitive
Used during dim lighting conditions
120 million per retina

31

Which retinal contains the blind spot

Nasal retina
-usually bigger

32

What is the distribution of rods to cones like in the retina

Rods are more likely to be on the periphery (except on the fovea and blind spot)
Cones are concentrated in our central vision (fovea)

33

What is the optic disk

The blind spot in which no photoreceptors are present, there all the ganglion cell axons gather to form the optic nerve

34

What is the fovea

A pit in the back of the retina where ganglion and bipolar cells are pushed to the side. This allows for the light to have an easier time striking the photoreceptors

35

What is the blind spot

Area without receptors
-1 million ganglion cell axons leave the eye from the optic nerve

36

What is phototransduction

converting light into electricity
-photoreceptor segment is where this occurs