the eye

Question 1

receptors definition

Answer 1

specialized cells that detect stimuli and convert them into nerve impulses

Question 2

photoreceptors

Answer 2

receptors which detect light stimuli

Question 3

position of the eye

Answer 3

two eyes positioned in bony eye sockets at the front of the skull

Question 4

eye structure

Answer 4

• spherical ish and has six eye muscles which help w movement
• front of eye is covered by conjunctiva
• tear gland is above the eye

Question 5

conjunctiva

Answer 5

thin mucous membrane which triggers a blink reflex when foreign objects enter the eye

Question 6

things that protect the eye

Answer 6

eyelids, eyelashes

Question 7

tear gland

Answer 7

secreted antiseptic tears that protect the conjunctiva from bacteria and dehydration

Question 8

three layers of the eye

Answer 8

outer fibrous
middle vascular
inner light-sensitive retina

Question 9

outer fibrous consists of

Answer 9

sclera

cornea

Question 10

cornea

Answer 10

transparent part of the sclera, allows light rays through to the inner layers of the eye and refracts them

Question 11

sclera

Answer 11

a strong white connective tissue that forms the outer layer of the eyeball
- protects internal parts, serves for muscle attachment

Question 12

middle vasc layer consists of

Answer 12

choroid
ciliary body
iris
also: pupil; lens; susp ligaments

Question 13

choroid

Answer 13

a thin, dark vascular layer

pigment absorbs excess light rays to prevent blurred images

Question 14

ciliary body

Answer 14

a thickening of the front of the choroid, consisting of ciliary muscles and is attached to the lens by suspensory ligaments

Question 15

ciliary body functions

Answer 15

contract and relax to change lens curvature during accomodation

Question 16

iris

Answer 16

• round structure in the middle of the eye

- at the front of the lens and contains pigments to give it color

Question 17

pupil

Answer 17

opening in the middle of the iris through which light rays enter the eye

Question 18

iris function

Answer 18

regulates the amount of light that enters the eye by controlling pupil size

Question 19

lens

Answer 19

rubbery elastic structure that changes shape

Question 20

lens function

Answer 20

changes shape to refract light rays and form an image on the retina

Question 21

inner-light sensitive retina consists of

Answer 21

pigment layer
nervous tissue layer
yellow spot
optic nerve

Question 22

pigment layer

Answer 22

outer layer that is in contact w choroid

pigment absorbs light rays, prevents internal reflection

Question 23

nervous tissue layer

Answer 23

consists of rods and cones which detect light stimuli (photoreceptors)

Question 24

rods

Answer 24

are stimulated in low light and give rise to b&w vision

Question 25

cones

Answer 25

stimulated in high light intensity and give rise to intense color vision

Question 26

yellow spot function

Answer 26

where the clearest most accurate image is formed

Question 27

function of optic nerve

Answer 27

conducts nerve impulses to the brain where they are interpreted to give sensation of sight

Question 28

divisions of the lens

Answer 28

anterior cavity | posterior cavity filled w vitreous humor (behind)

Question 29

anterior cavity

Answer 29

in front, aqueous humor anterior chamber - betw cornea and iris posterior - betw iris and lens

Question 30

vitreous humor functions

Answer 30

- maintains eyeball shape - refracts light rays - hold retina in position

Question 31

what is the pupillary mechanism

Answer 31

reflex action which responds to the stimulus of the amount of light that enters the eye

Question 32

pupillary mechanism process

Answer 32

``` BRIGHT LIGHT radial musc relax (RR) circular musc contract (CC) pupil constricts less light vice versa for low light ```

Question 33

accommodation

Answer 33

the process during which the eye adapts for the observation of nearby objects (6m) by changing the lens shape

Question 34

accommodation for distant objects

Answer 34

``` circular musc relax (CR) ciliary body further away from lens sus lig are taut (slacken) lens less convex less light refracted sharp focused image on retina ```

Question 35

binocular vision

Answer 35

each eye forms its own image of the object, brain combines the two images to form a 3D image

Question 36

what binocular vision does

Answer 36

provides a wider field of vision and depth perception

Question 37

stereoscopic vision

Answer 37

the ability to see in 3D

Question 38

myopia

Answer 38

- short sightedness | - elongated eyeball, cornea curve

Question 39

fixing myopia

Answer 39

- concave lenses to diverge rays before they enter the eye | - laser surgery

Question 40

hypermetropia

Answer 40

shorter eyeball, flat cornea

Question 41

correcting hypermetropia

Answer 41

convex lenses, converges light rays to focus on the retina | laser surgery

Question 42

astigmatism

Answer 42

causes light rays to focus on more than one focal point - causes a blurry image - glasses, contacts, lasers

Question 43

cataracts

Answer 43

the clouding of the eyes lens, prevents light from reaching the retina, blurred vision - initially glasses, or laser surgery