5.1 neuro - vision

Question 1

what are the three layers (tunics) of the eyeball

Answer 1

outer fibrous, intermediate vascular layer, inner neural layer

Question 2

what are they layers of the eyeball also referred to as

Answer 2

tunics

Question 3

fibrous tunic (what, made of what)

Answer 3

the outer layer of the eyeball, strong dense collagenous connective tissue layer

Question 4

what are the two division of the fibrous tunic

Answer 4

sclera, cornea

Question 5

is the cornea vascular or avascular

Answer 5

avascular

Question 6

cornea (what, function)

Answer 6

transparent anterior surface of the fibrous tunic, main refractive index of the eye

Question 7

sclera (what, function)

Answer 7

tough opaque outer covering, forms the white part of the eye, provides protection, maintains the shape of the eyeball, serves as the site of muscle attachment for the extrinsic muscles

Question 8

what are the three parts of the vascular tunic

Answer 8

choroid, ciliary body, iris

Question 9

what is the vascular tunic

Answer 9

middle layer of the eyeball

Question 10

what is the choroid of the vascular tunic (vascular/avascular, function)

Answer 10

highly vascularized, provides nutrients to the posterior (deep) surface of the retina, lines most of the sclera

Question 11

what is the ciliary body

Answer 11

anterior portion of the vacular tunic

Question 12

what does the ciliary body consist of

Answer 12

ciliary process and ciliary muscle

Question 13

what does the ciliary process do

Answer 13

contains capillaries and secretes aqueous humor

Question 14

what extends from the ciliary process and where do they attach

Answer 14

zonular fibers (suspensory ligaments) that attach to the lens

Question 15

what do ciliary muscles do

Answer 15

contraction or relaxation of the ciliary muscles changes the tension on the zonular fibers, which alters the shape of the lense, adapting it for near and far vision

Question 16

how are ciliary muscles arranged

Answer 16

longitudinal, oblique, and circularly

Question 17

what is the iris

Answer 17

colored part of the eye

Question 18

what muscles control the diameter of the pupil

Answer 18

sphincter and dilator muscles in the iris

Question 19

what proteins are in the lens and what do they do

Answer 19

crystallin, make up refractive media of the lens, arranged like layers of an onion

Question 20

is the lens of the eye vascular or avascular

Answer 20

avascular

Question 21

are constrictor pupillae (circular) innervated by sympathetic or parasympathetic fibers

Answer 21

parasympathetic

Question 22

are dilator pupillae (radial) innervated by sympathetic or parasympathetic fibers

Answer 22

sympathetic

Question 23

what is the function of the iris

Answer 23

muscles control the diameter of the pupil

Question 24

what two layers does the retina consist of

Answer 24

pigmented layer, neural layer

Question 25

what is the pigmented layer of the retina and what does it do

Answer 25

sheet of melanin-containing epithelial cells, helps to absorb stray light rays

Question 26

what are the 3 layers of retinal neurons

Answer 26

photoreceptive layer, bipolar cell layer, ganglion cell layer

Question 27

what two types of cells are present in the bipolar retinal neuron layer and what do they do

Answer 27

horizontal cells and amacrine cells - modify the signal

Question 28

what are the two types of photoreceptors

Answer 28

rods and cones

Question 29

what do rods do

Answer 29

allow us to see in dim light

Question 30

what do cones do

Answer 30

bright light stimulates the cones which produce color vision

Question 31

what does the photoreceptor layer of the retina do

Answer 31

detect light

Question 32

what does the bipolar layer of the retina do

Answer 32

relay to ganglion neurons

Question 33

what does the ganglion layer of the retina do

Answer 33

output to the thalamus

Question 34

what is the retinal pigmented epilthelium

Answer 34

nonvisual portion, absorbs stray light and helps keep vision clear

Question 35

what is the optic disc

Answer 35

where CN II exits the eyeball

Question 36

what is CN II formed of

Answer 36

collected axons of the ganglion layer neurons

Question 37

what does the central retinal artery supply

Answer 37

branches to supply nourishment to retina

Question 38

what veins and arteries travel within the optic nerve

Answer 38

central retinal artery, branch of the ophthalmic artery, and the central retinal vein

Question 39

what and where is the macula latea

Answer 39

yellow spot, fewer blood vessels, in in the exact center of the posterior portion of the retina, at the visual axis of the eye

Question 40

what portion of the eyeball does the retina cover

Answer 40

posterior 3/4

Question 41

what and where is the fovea centralis

Answer 41

small depression at the center of the macula lutea, contains only cones and is the area of highest visual acuity or resolution

Question 42

are there rods or cones in the optic disc

Answer 42

neither, blind spot

Question 43

what does the interior cavity of the eye consist of

Answer 43

two fluid filled cavities anterior cavity: between the cornea and lens, contains aqeous humor posterior cavity: vitreous cavity / chamber, more gel-like, helps hold the retina in place

Question 44

what is the purpose of vitreous humor in the posterior cavity

Answer 44

supports the retina and lens

Question 45

list the light pathway through the eye in order

Answer 45

cornea, aqueous humor, pupil, lense, vitreous humor, ganglion cell layer (retina), rods and cones (retina)

Question 46

list the visual information pathway for vision in order

Answer 46

rods and cones, ganglion cell layer, optic nerve, optic chiasm, optic tract, lateral geniculate body, visual cortex area 17

Question 47

do gangion cell axons cross the midline at the optic chiasm

Answer 47

half do half don't