Eye And Retina

Front 1

two functions of eyes

Back 1

focus light and transduction

Front 2

fibrous cover of eye (white of the eye)

Back 2

sclera

Front 3

window into eye; main refractive element

Back 3

cornea

Front 4

forms pupil

Back 4

iris

Front 5

acellular fluid that pressurizes the eye

Back 5

Aqueous humor

Front 6

ligaments that suspend the lens

Back 6

zonule fibers

Front 7

consists of ciliary processes and ciliary muscle

Back 7

ciliay body

Front 8

produce and secrete aqueous humor

Back 8

ciliary process

Front 9

controls shape of the lens

Back 9

ciliary muscle

Front 10

blood supply plexus serving outer retina, ciliary body and iris

Back 10

choroid

Front 11

are near central retina with high concentration of photoreceptors

Back 11

fovea

Front 12

axons of retinal ganglion cells exiting the retina

Back 12

optic nerve

Front 13

The blood supply of the eye is provided by 2 branches of the opthalmic artery.
What are they?

Back 13

Central retinal artery and long and short ciliary arteries

Front 14

these form the chorid plexus betwen the sclera and the retinal pigment epithelium

Back 14

long and short ciliary arteries

Front 15

enters with the optic nerve and ramifies to supply blood to the inner retina

Back 15

Central retinal artery

Front 16

layer of pigmented cells next to photoreceptors. These cells absorb stray light and increase fidelity of image

Back 16

Retinal pigment epithelium (RPE)

Front 17

these two components of the eye lack vascularization

Back 17

lens and cornea

Front 18

normal vision in which light focused at the level of the retina

Back 18

emmetropia

Front 19

when light is focused behind the retina due to abnormal eye shape (too short) or not enough refractive power provided by cornea and lens

Back 19

hypermetropia or hyperopia

Front 20

how to correct hyperopia

Back 20

convex lens

Front 21

hen light is focused in front of the retina due to abnormal eye shape (too long) or too much refractive power provided by cornea and lens

Back 21

myopia

Front 22

how to correct myopia

Back 22

concave lens

Front 23

two roles of the cornea

Back 23

refraction and protection

Front 24

the corena is highly innervated

true or false

Back 24

true

Front 25

what provides the innervation for the cornea

Back 25

ciliary nerves from the opthalamic branch of CN V

Front 26

main functions of the lens

Back 26

refraction and accomidation

Front 27

the shape of the lens changes depending on the refractive power needed in a given circumstance via what reflex?

Back 27

accomodative

Front 28

does a round or flat lens bend light more

Back 28

round

Front 29

a spherical lens is used for far or near objects?

Back 29

near

Front 30

when the ciliary muslce is contracted the lens is in what shape?

Back 30

round

Front 31

when the ciliary muslce is relaxed the lens is in what shape?

Back 31

flat

Front 32

describe the innervation of the accomodation reflex

Back 32

EW nucleus – preganglionic parasympathetic

Ciliary ganglion - short ciliary nerves

Ciliary muscle and pupillary constrictor

Front 33

blood-derived acellular fluid
pressurizes the eye – maintains eye shape
produced by ciliary body
flows from posterior to anterior chamber
drains through trabecular network and Canal of Schlemm
clinical – increased IOP/cupping of optic nerve head/glaucoma

Back 33

aqueous humor

Front 34

place behind the iris and in front of the ciliary fibers

Back 34

posterior chamber

Front 35

place where the aqueous humor drains

Back 35

trabecular network through the Canal of Schlemm

Front 36

layers of the retina

Back 36

retinal pigment epithelium - metabolic support of outer retina
2. photoreceptor outer segment- light sensitive elements
3. photoreceptor inner segment - synthetic machinery
4. outer nuclear - photoreceptor cell bodies
5. outer plexiform - photoreceptor / relay neuron synapses
6. inner nuclear - relay neuron cell bodies
7. inner plexiform - relay neuron/ganglion cell synapses
8. ganglion cell - ganglion cell bodies
9. nerve fiber - ganglion cell axons

Front 37

area of the retina that only has cones

Back 37

fovea

Front 38

ganglion cells and other fibers deviated to the side to provide unobstructed light path to foveal cones. – atypical- the light does not have to pass all the other layers to reach the rods and cones

Back 38

foveal pit

Front 39

in darkness the photo cells are depolarized or hyperpolarized

Back 39

depolarized

Front 40

when illuminated the photo cells are depolarized or hyperpolarized

Back 40

hyperpolarized

Front 41

the membrane potential of the photocells can range from -40 to -70 depending on

Back 41

light intensity

Front 42

name the activity of photocells

Back 42

1) light activates outer segment photopigments (rhodopsin, 3 cone opsins)

2) activated photopigments undergo conformational change triggering
a cascade that results in a decrease in cytosolic cGMP concentration

3) cGMP gated Na+ channels close, Na+ influx reduced, cell is hyperpolarized (i.e., more negative inside)

Front 43

graded potential related to overall light level

Back 43

photoreceptors

Front 44

center surround antagonism

Back 44

bipolar circuit

Front 45

receive input from bipolar cells also have center-surround organization and contrast sensitivity. However, unlike the graded membrane potentials of photoreceptors and bipolar cells, these cells respond with action potentials and signal changes in visual contrast with changes in the rate of action potentials.

Back 45

ganglion cells

Front 46

bipolar cell is excited by light in the center and inhibited by light falling on the surround

Back 46

On center

Front 47

inhibited by light on the center and excited by the lack of light in the periphery

Back 47

Off Center

Front 48

large receptive fields
fast, transient responses
good for detecting motion
color insensitive

Back 48

M-ganglion cells

Front 49

small receptive fields
slow, sustained response
texture fine form analysis
motion insensitive
color sensitive

Back 49

P-ganglion cells

Front 50

where in the thalamus do retinal ganglion cells synapse?

Back 50

LGN

Front 51

visual space is represented contralaterally or ipsilaterally in the brain

Back 51

contralaterally

Front 52

sensitivity to the orientation of contrast borders is first seen in the

Back 52

primary visual cortex

Front 53

cell “tuned” for border orientation

Back 53

simple cell

Front 54

the cube is divided into two ________ one for ipsilateral layers and one for contralateral layers

Back 54

ocular dominance columns

Front 55

the color selective region of the parvocellular pathway

Back 55

blobs

Front 56

oriented perpendicular to the 6 layers of cortex and each column represents a restricted region of visual space. Within each, fine form, orientation, motion, and color are all represented, as are inputs deriving from both the contralateral and ipsilateral eyes.

Back 56

hypercolumn or cube

Front 57

contralateral column receives input deriving from the contralateral eye via layers 1 (magnocellular), 4 & 6 (parvocellular) of the LGN. The ipsilateral column receives input deriving from the ipsilateral eye via layers 2 (magnocellular), 3 & 5 (parvocellular) of the LGN.

Back 57

ocular dominance column

Front 58

Cells within a column prefer a certain stimulus orientation. Within a single ocular dominance column there are enough orientation columns to represent all orientations from 0 to 360 degrees.

Back 58

orientation columns

Front 59

the M cells with motion and space information travel to the _____ part of the cortex via the _______ layer of the LGN

Back 59

Layer 4Caplha
magnocellular (ventral)

Front 60

the P cells with form information travel to the _____ part of the cortex via the _______ layer of the LGN

Back 60

Layer 4Cbeta
Parvocellular layer (dorsal)

Front 61

the P cells with color information travel to the _____ part of the cortex via the _______ layer of the LGN

Back 61

Layer 2,3 Blobs
Parvocellular and intralaminar regions

Front 62

the most territory on the cortex is devoted to the _______ visual field

Back 62

central

Front 63

)- the part of the optic radiations that bulges laterally into temporal cortex. These fibers course around the inferior horn of the lateral ventricle and carry information deriving from the inferior temporal retina of the ipsilateral eye (uncrossed retinal projection) and from the inferior nasal retina of the contralateral eye (crossed retinal projection) and thus represent the superior quadrant of contralateral space.

Back 63

Meyer's Loop

Front 64

Due the amount of neural tissue devoted to central visual space (e.g., cortical magnification factor), vision is spared in the parafoveal region because lesions are rarely extensive enough to obliterate the entire magnified cortical representation of central vision.

Back 64

Macular Sparing