Eyeballs

Question 1

What is the sclera?

Answer 1

White of the eye

Question 2

How does the eye move in orbit?

Answer 2

3 extra ocular muscles

Question 3

What are the two parts of the lens?

Answer 3

Aqueous humor and vitreous humor

Question 4

What is the aqueous humor?

Answer 4

Nourishes cornea and is watery

Question 5

What does the vitreous humor do?

Answer 5

Keep eye spherical, is 80% of the eyeball, and has phagocytic cells that remove debris

Question 6

What is the choroid?

Answer 6

The capillary bed that provides blood to the photoreceptors

Question 7

What is visual acuity?

Answer 7

Ability to distinguish two points that are close to each other (depends on space of photoreceptors)

Question 8

Where do photoreceptors sit?

Answer 8

Pigment epithelium

Question 9

What does the pigment epithelium do?

Answer 9

Reduces backscatter and renews photopigments and phagocytoses photoreceptor disks

Question 10

What is the reflective layer beneath the photoreceptor layer?

Answer 10

Tapetum lucidum (causes eye shine)

Question 11

Are there more rods or cones?

Answer 11

Rods (18x more)

Question 12

What is contained in the membranous disks of photoreceptors?

Answer 12

Opsins

Question 13

What photopigment is contained in rods?

Answer 13

Rhodopsin

Question 14

Are cones or rods more sensitive to light?

Answer 14

Rods are 1000x more sensitive

Question 15

What type of photopigment do cones have?

Answer 15

3, one for each color (blue, green, red)

Question 16

What does scotopic mean?

Answer 16

Darkness lightning, relies on rods

Question 17

What does photopic mean?

Answer 17

Daytime lighting, mostly cones

Question 18

What photoreceptor is 100% present in the fovea

Answer 18

Cones

Question 19

What is the ratio of photoreceptors to ganglion cells in the fovea?

Answer 19

1:1

Question 20

What type of vision is the fovea best at seeing?

Answer 20

High rest vision

Question 21

Are there more rods or cones in the peripheral retina?

Answer 21

Rods

Question 22

What type of lighting is the peripheral retina best at seeing?

Answer 22

Dim light

Question 23

How is a visual pigment molecule formed? (The components)

Answer 23

A chromophore (11-cis retinal) and an opsin

Question 24

Why is 11-cis retinal important

Answer 24

It changes shape when hit with light

Question 25

What is an opsin?

Answer 25

A GPCR

Question 26

Are rods depolarized or or hyper polarized in the dark?

Answer 26

Depolarized, steady Na+ flow inside

Question 27

What are the Na+ channels in the rods gated by?

Answer 27

CGMP, produced by guanylyl cyclase

Question 28

What happens when light hits the photoreceptors

Answer 28

Rhodopsin is stimulated, activates transducin, transducin actives PDE, PDE turn cGMP into GMP, Na+ leaves the cell and causes the cell to be hyperpolarized

Question 29

What receptors are on ON bipolar cells?

Answer 29

mGluR6, causes depolarization when glutamate isn’t present

Question 30

What receptors are on OFF bipolar cells?

Answer 30

AMPA receptors, causes hyperpolarization when glutamate is present

Question 31

What do horizontal cells do?

Answer 31

Inhibit the center photoreceptor with GABA-like NTs (only when glutamate hits the horiz cells)

Question 32

What is the emphasis of contrasting light and dark edges called?

Answer 32

Luminance contrast

Question 33

What are the 3 types of ganglion cells?

Answer 33

M-type, P-type, nonM-nonP type ganglion cells

Question 34

What are some characteristics of M cells?

Answer 34

Larger receptive fields, APs are faster, low rest vision contribution, fires via transient bursts

Question 35

What are some characteristics P cells?

Answer 35

Smaller receptive fields, high res vision contribution, fire sustained APs

Question 36

What are the % populations of each of the retinal ganglion cells?

Answer 36

90% P-type, 5% M-type, 5% nonM-nonP type

Question 37

What are the color opponents combinations?

Answer 37

Blue/Yellow and Green/Red

Question 38

What are the Retinal ganglion cells that respond to sunlight and aid circadian rhythms?

Answer 38

IpRGCs

Question 39

What is the opsin in ipRGCs?

Answer 39

Melanopsin

Question 40

What is the optic chiasm?

Answer 40

A partial decussation of the optic nerves

Question 41

What crosses the optic chiasm? Temporal or Nasal?

Answer 41

Nasal

Question 42

Where to ganglion cell axons terminate?

Answer 42

LGN (located in thalamus)

Question 43

What does the Suprechaismatic nucleus (SCN) of the hypothalamus do?

Answer 43

Controls circadian rhythms

Question 44

Where is the pretectum? What does it control?

Answer 44

Between thalamus and midbrain, controls pupil size

Question 45

What does the superior colliculus do?

Answer 45

Orients eye towards new stimuli, basically moving ur eye towards something the brain finds interesting

Question 46

What’s the difference between visual field and hemifield?

Answer 46

Visual field is the entire region ur eyes see straight ahead, the hemifield is the imaginary halves of ur vision

Question 47

What side of the brain does the left hemifield project to?

Answer 47

Right

Question 48

What side of the brain does the right hemifield project to?

Answer 48

Left

Question 49

What would a lesion to the left optic nerve do?

Answer 49

No vision in left periphery

Question 50

What would a lesion in the left optic track do?

Answer 50

No vision in the right hemifield

Question 51

What would happen if you lesion the optic chiasm?

Answer 51

All periphery would be lost

Question 52

How many layers are there in the LGN?

Answer 52

6

Question 53

What layers are ipsilateral in the LGN?

Answer 53

2, 3, and 5

Question 54

What layers are contralateral in the LGN?

Answer 54

Layers 1,4, and 6

Question 55

What layers in the LGN are M-type?

Answer 55

1 and 2

Question 56

What layers in the LGN are P-type?

Answer 56

3-6

Question 57

Are M-type or P-type ganglion cells sensitive to differences in wavelength?

Answer 57

P-type

Question 58

What is the Primary Visual Cortex?

Answer 58

V1

Question 59

What area in the retina is overrepresented in V1?

Answer 59

Central retina (aka fovea)

Question 60

What is the breakdown on the 6 (really 9) layers of V1?

Answer 60

Layer 1 Layer 2 Layer 3 Layer 4A Layer 4B Layer 4Ca Layer 4Cb Layer 5 Layer 6

Question 61

Which layer is the primary recipient of LGN afferents?

Answer 61

4C

Question 62

What is contained in layer 4C?

Answer 62

Spiny Stellate cells which make connections within the cortex

Question 63

What layers are pyramidal cells found in?

Answer 63

Layer 3, Layer 4B, Layer 5, Layer 6

Question 64

What do the pyramidal cells do in V1?

Answer 64

Send axons OUT of V1

Question 65

Which sub layer in Layer 4C are M-cell LGN neurons?

Answer 65

Alpha

Question 66

Which sub layer in Layer 4 are P-type LGN neurons in?

Answer 66

Beta

Question 67

What are the intra-cortical connections?

Answer 67

Layer 4Ca -> Layer 4B & Layer 4Cb -> Layer 3

Question 68

Which neurons are binocular?

Answer 68

Most neurons outside of layer 4C

Question 69

What is the word for being able to recognize depth perception?

Answer 69

Stereopsis

Question 70

Where do Layer 2, 3, and 4B project to?

Answer 70

Other cortical areas

Question 71

Where does Layer 5 project to?

Answer 71

Superior colliculus and pons

Question 72

Where does Layer 6 project to?

Answer 72

Back to the LGN

Question 73

What is a neuron being more sensitive to one orientation called?

Answer 73

Orientation selectivity

Question 74

What are subsets of cells that are sensitive called? ____ selective

Answer 74

Direction

Question 75

What type of neuron is synonymous for being direction selectivity?

Answer 75

M-type (think: motion)

Question 76

What is the dorsal stream meant for?

Answer 76

Navigation, directing eye movements, motion perception (basically movement, M-type cells)

Question 77

What is the ventral stream for?

Answer 77

Facial recognition, shape and colors, and potentially visual perception and visual memory (P-type cells)