Eye Anatomy

Question 1

Eye

description? how many layers? what are they?

Answer 1

2.5 diameter
wall of eyeball consists of 3 layers:
-fibrous tunic: outer layer 
-vascular tunic: middle layer 
-retina: inner layer

Question 2

Fibrous Tunic

composed of ? (2)

Answer 2

cornea

sclera

Question 3

Cornea

description? what does it do?

Answer 3

transparent covering of iris
admits & refracts light into eye- helps focus light onto retina
(bulges out)

Question 4

Sclera

description? what does it do?

Answer 4

(cornea turns into this)
“white” of the eye- dense connective tissue
provides shape to eyeball (outer layer)
attachment for eye muscles

Question 5

Vascular Tunic (Uvea) 
composed of ? (3)

Answer 5

(called Uvea bc of UV light)
choroid
ciliary body
iris

Question 6

Choroid

function? location? description? contains? which do what?

Answer 6

lines sclera
posterior portion of tunic
vascular
contains melanocytes- appears black/brown
-prevents reflection & scattering of light

Question 7

Ciliary body

Answer 7

anterior portion of tunic
contains melanocytes (dark brown appearance)
parts:
 -ciliary processes
 -ciliary muscle

Question 8

ciliary processes definition?

Answer 8

vascular folds of internal surface of ciliary body

- secretes aqueous humor (watery)

Question 9

ciliary muscle definition ?

Answer 9

(connected to iris)
circular band of smooth muscle
-muscle contraction changes lens shape
-adapts for near or far vision

Question 10

iris

description? how is color determined? location? made of? function?

Answer 10

colored portion of eyeball 
 -determined by amount of melanin 
attached to ciliary processes
made of melanocytes & smooth muscle fibers
regulates amount of light into eyeball

Question 11

pupil

Answer 11

opening in center of iris\

Question 12

coloboma

Answer 12

irregular shaped iris
-pupil is NOT circular
(does not affect sight, happens in fetus)

Question 13

heterochromia iridum

Answer 13

2 different colored iris

EX: blue and green eye

Question 14

Lens, is it part of vascular tunic?

Answer 14

No, its not a part of the vascular tunic, it only sits in that area

Question 15

Lens
description?
contains?
function?

Answer 15

(hard & semi-transparent)
behind pupil & iris
contains proteins - crystallins
    -arranged in layers
lacks blood vessels
helps focus images on retina (help focus light on it)

Question 16

Interior eyeball cavities

whats divided into 2 cavities? what are they?

Answer 16

lens divides eye into 2 cavities :
anterior cavity
vitreous chamber (posterior cavity)

Question 17

Anterior cavity

filled with? functions?

Answer 17

(watery)
filled w/ aqueous humor
-maintains shape of eyeball
-supplies oxygen & nutrients to lens & cornea

Question 18

Posterior cavity aka Vitreous Chamber

Answer 18

(jelly)
Large cavity behind lens
-filled w/ vitreous body
    -jelly-like substance
    -maintain shape of eyeball
    -keeps retina attached to choroid

Question 19

how are the cavities held together?

Answer 19

held together by pressure

Question 20

retina

description? consists of?

Answer 20

inner layer of eyeball, posterior 3/4 of eyeball
Consists of:
-pigmented layer- melanin
-neural (sensory) layer- processes visual data

Question 21

Pigmented layer

Answer 21

(contains melanin)

helps absorb light rays

Question 22

Neural (sensory) layer

Answer 22

(processes visual data)
3 layers:
-Photoreceptors (rods & cones)
-Bipolar cell layer 
-Ganglion cell layer

Question 23

Other Areas on Retina (3)

Answer 23

Macula lutea
Fovea centralis
Optic disc

Question 24

Macula lutea

description? location?

Answer 24

small flat spot
exact center posterior region of retina
visual axis of eye

Question 25

``` Macular Degeneration (in macula lutea) where does it occur? what is it? what happens? ```

Answer 25

Degenerative disorder of retina - occur in region of macula lutea - lose acute vision, but have peripheral vision

Question 26

Fovea centralis | location? contains? known for?

Answer 26

small depression in center of macula lutea contains ONLY CONES area of highest visual resolution

Question 27

Optic disc | location? also known as?

Answer 27

where ganglion axons collect & exit eyeball as optic nerve 1 (joins which is why its #1) AKA 'blind spot' - no rods & cones

Question 28

Photoreceptors of Retina | function? what are the photoreceptors of retina? (2)

Answer 28

convert high rays to nerve impulse - rods - cones

Question 29

rods | how many? allows/ does not allow?

Answer 29

120 million enables to see dim light does NOT provide color vision (dark & light adjustments)

Question 30

cones | how many? types?

Answer 30

6 million stimulated by bright light 3 types: blue (blue light), Green (green light), Red (right light) -color vision results from combinations of the 3 types of cones being stimulated

Question 31

Image Formation (3)

Answer 31

1) Refraction (bending) of light rays 2) Accommodation 3) Constriction (narrowing) of Pupil

Question 32

Refraction (bending) of light rays

Answer 32

75% refraction through cornea 25% refraction through lens image is inverted on retina

Question 33

Accommodation | what is it? depends on? what controls it?

Answer 33

``` change in shape of lens depends on distance of object -distance objects: lens is flatter (ciliary muscles pull) -close objects: lens is more spherical ciliary muscle controls lens shape ```

Question 34

Constriction (narrowing) of Pupil

Answer 34

circular muscles of iris control pupil diameter

Question 35

Photopigments & vision | function? description? contain?

Answer 35

``` absorb light colored protein molecules initiates events for nerve potentials rods contain rhodosin -purplish color cones contains 3 different types of pigments photopigments contain: -opsin -retinal ```

Question 36

opsin

Answer 36

protein molecule (photopigment contains this)

Question 37

retinal

Answer 37

(photopigment contains this) vitamin A derivative -light absorbing part of photopigment

Question 38

Brain pathway & visual fields | types of visual fields? binocular vision?

Answer 38

binocular vision- both eyes focus on 1 set of objects Each eye visual field: Nasal (Central) half Temporal (Peripheral) half

Question 39

Nasal (Central) half

Answer 39

light rays from nasal half will fall on the temporal half of the retina

Question 40

Temporal (Peripheral) half

Answer 40

light rays from temporal half will fall on the nasal half of the retina

Question 41

how is visual info conveyed ?

Answer 41

visual info from the RIGHT half of each visual field is conveyed to the LEFT side of the brain and vice versa

Question 42

nearsighted/ farsightedness | another name for each?

Answer 42

nearsightedness - myopia | farsightedness - hyperopia

Question 43

nearsightedness (myopia) | corrected with? what is it? where?

Answer 43

see close objects focal point in front of retina corrected w/ concave lens

Question 44

farsightedness (hyperopia) | what is it? where? corrected with?

Answer 44

see far objects focal point behind retina corrected w/ convex lens

Question 45

Astigmatism | definition?

Answer 45

either cornea or lens has irregular curvature | get multiple focal points- parts of image is unfocused or distorted

Question 46

choroid , choroid coat

Answer 46

posterior 5/6 of middle (vascular) layer loosely joined to sclera

Question 47

sclera

Answer 47

white part of outer (fibrous) layer

Question 48

cornea

Answer 48

transparent anterior portion of outer layer

Question 49

conjunctiva

Answer 49

inner lining of eyelid

Question 50

lacrimal gland

Answer 50

secretes tears

Question 51

vitreous humor

Answer 51

fills posterior cavity

Question 52

optic disc

Answer 52

area where optic nerve exits eye

Question 53

iris

Answer 53

smooth muscle that controls light entering the eye

Question 54

aqueous humor

Answer 54

fills anterior and posterior chambers of anterior cavity of the eye

Question 55

retina

Answer 55

contains visual receptors called rods & cones

Question 56

suspensory ligaments, zonula fibers

Answer 56

connects lens to ciliary body

Question 57

ciliary muscle

Answer 57

cause lens to change shape

Question 58

structures & fluids through which light passes as it travels from the cornea to retina

Answer 58

``` cornea aqueous humor pupil of iris lens vitreous humor retina ```

Question 59

what tissue is responsible for the toughness in the eye?

Answer 59

dense connective tissue

Question 60

where's aqueous humor in the eye?

Answer 60

anterior cavity (btwn cornea and lens)

Question 61

function of dark pigment in choroid coat?

Answer 61

absorbs excess light

Question 62

Extrinsic eye muscle: superior rectus

Answer 62

up and in

Question 63

Extrinsic eye muscle: medial rectus

Answer 63

inward

Question 64

Extrinsic eye muscle: inferior oblique

Answer 64

up and out

Question 65

Extrinsic eye muscle: inferior rectus

Answer 65

down and in

Question 66

Extrinsic eye muscle: lateral rectus

Answer 66

outward

Question 67

Extrinsic eye muscle: superior oblique

Answer 67

Down and out