Vision

Question 1

eyes

Answer 1

use photoreceptors to help form visual images of the environment

Question 2

extrinsic muscles (accessory structures)

Answer 2

move eyeball

Question 3

eyelids (accessory structures)

Answer 3

structures made of skin to protect the eye

Question 4

medial canthus (accessory structure)

Answer 4

where upper lid and lower lid meet on medial side

Question 5

lateral canthus (accessory structure)

Answer 5

where lids meet on lateral side

Question 6

lacrimal caruncle (accessory structure)

Answer 6

pink, fleshy area in medial corner of eye

Question 7

conjuctiva

Answer 7

lining of the eyelids and over the anterior surface of the eye (excluding cornea)

Question 8

lacrimal apparatus

Answer 8

produces, collects and drains lacrimal fluid (tears) from the eye

Question 9

tears…

Answer 9

lubricate the anterior surface of the eye

Question 10

lacrimal gland

Answer 10

cloud, upper lateral portion, produces tears (blinking spreads tears around the eye)

Question 11

lacrimal canaliculi

Answer 11

little canals that drain tears

Question 12

lacrimal sac

Answer 12

where tears collect

Question 13

nasolacrimal duct

Answer 13

where tears drain into nasal cavity

Question 14

tears pathway

Answer 14

lacrimal gland -> lacrimal canaliculi -> lacrimal sac -> nasolacrimal duct

Question 15

anterior cavity

Answer 15

in front of lens (between cornea and lens) contains circulation aqueous humor (watery fluid)

Question 16

posterior cavity

Answer 16

behind the lens, contains permanent vitreous humor (thicker)

Question 17

eye wall 3 layers

Answer 17

fibrous tunic: outermost (thickest)
vascular tunic: intermediate
retina: inner

Question 18

glaucoma

Answer 18

increased intra-eye pressure
- effects retina and optic nerve

Question 19

fibrous tunic

Answer 19

cornea: transparent anterior portion of the eyeball
sclera: most abundant, white of eye

Question 20

vascular tunic (blood flow)

Answer 20

• choroid: contains vast network of capillaries supplying nutrients and oxygen to the retina (outer layer below sclera) posterior
• ciliary body: changes lens shaped, coroid
• iris: pigmented part of the anterior eye; defines pupil - controls amount of light entering eye (muscular)

Question 21

circular sphincter pupilae

Answer 21

close things, adjacent to pupil, decreases opening/size of pupil

Question 22

radial dilatory pupillae

Answer 22

dilate the pupil

Question 23

retina

Answer 23

internal layer of the eye (deepest)

Question 24

neural layer

Answer 24

houses photoreceptors and associated neurons
- receives light; converts energy into nerve impulses

Question 25

3 layers form neural layer

Answer 25

- photoreceptors: outermost layer composed of rods and cones (rods important in dim light, cones important for precise vision and color) - bipolar cells: synapse with photoreceptors and ganglion cells - ganglion cells: innermost layer of the retina; axons of these cells leave the retina and form the optic nerve (CN II)

Question 26

rods

Answer 26

- 120 million/retina - more numerous in the periphery - night vision - low acuity (ability to distinguish detail) - vision in shades of grey

Question 27

cones

Answer 27

- 6 million/retina - concentrated in the fovea - day vision - high acuity - color vision

Question 28

the optic disc...

Answer 28

is a "blind spot" on the retina lacking photoreceptors

Question 29

fovea centralis

Answer 29

depression in the retina containing the highest proportion of cones and almost no rods - area of sharpest vision - located within the macula lutea (lateral to optic disc)

Question 30

lens

Answer 30

- transparent - suspensory ligaments attach to outer capsule of lens

Question 31

accomodation

Answer 31

ability of a lens to change shape - focus image on the back of the eye

Question 32

visual pathway

Answer 32

cornea -> anterior cavity -> lens -> posterior cavity -> retina (photoreceptors/rods and cones) -> CN II (optic nerve) -> optic chiasm -> optic tract -> optic radiation -> occipital lobe (perception)

Question 33

20/20

Answer 33

vision is normal

Question 34

20/< 20

Answer 34

vision is better than normal

Question 35

20/>20

Answer 35

vision is worse than normal

Question 36

nearsightedness (myopia)

Answer 36

difficulty seeing things far away - longer eye than normal

Question 37

farsightedness (hyperopia)

Answer 37

difficulty seeing things close up - eyeball is too short - corrective lens thicker in the middle and thinner on outside

Question 38

presbyopia

Answer 38

age related farsightedness

Question 39

astigmatism

Answer 39

irregularity of cornea or lens (usually a little bump) - light scatters when it hits the eye - treatment: corrective lens are very specific

Question 40

conjuctivitis (pink eye)

Answer 40

inflammation of the conjuctiva

Question 41

cataracts

Answer 41

lens becomes cloudy

Question 42

glaucoma

Answer 42

increased pressure within the eye

Question 43

diabetic retinopathy

Answer 43

cause blind spots, small unstable vessels developed along retina prone to bursting

Question 44

strabismus

Answer 44

misalignment of the eyes