The Eye

Question 1

What is refraction

Answer 1

bending of light due to difference in speed through different media

Question 2

How does light travel

Answer 2

straight lines

Question 3

How can light be manipulated

Answer 3

reflected, absorbed and refracted

Question 4

What is the cornea important for

Answer 4

refraction

Question 5

What is the function of the sclera

Answer 5

protection and maintenance of shape

Question 6

What is the function of extra ocular muscles

Answer 6

move the eyeball

Question 7

What controls the extra-ocular muscles

Answer 7

occulomotor nerve

Question 8

Describe the optic disk

Answer 8

where blood vessels and nerves come into the eye

Question 9

What is the function of the optic nerve

Answer 9

carries axons from the retina to the brain

Question 10

Describe the macula

Answer 10

region of retina, devoid of large blood vessels

Question 11

What is the function of the macula

Answer 11

central vision , quality of vision

Question 12

Describe the fovea

Answer 12

thin, area of highest visual acuity

Question 13

Where is the fovea located

Answer 13

macula

Question 14

What does the fovea contain

Answer 14

photoreceptors

Question 15

What is the aqueous humour

Answer 15

watery fluid

Question 16

What is the function of the aqueous humour

Answer 16

provide nutrients to cornea and lens

Question 17

When is the vitreous humour formed

Answer 17

embryonic development

Question 18

Function of the canal of schlemm

Answer 18

drain the aqueous humour

Question 19

What is the vitreous humour

Answer 19

viscous fluid - jelly like

Question 20

What is the function of the vitreous humour

Answer 20

keeps the eyeball spherical, pushes retina down, provides clearer images

Question 21

Name two diseases of the eye

Answer 21

cataracts, glaucoma

Question 22

What is attached to the lens

Answer 22

zonal fibres

Question 23

What is the function of zonal fibres

Answer 23

enable stretching of the lens

Question 24

Describe cataracts

Answer 24

clouding of the lens

Question 25

Why does cataracts occur

Answer 25

changes in composition of the aqueous humour

Question 26

What causes glaucoma?

Answer 26

slowed uptake of aqueous humour

Question 27

What are the symptoms of glaucoma

Answer 27

elevated intraocular pressure, compression of the optic nerve, reduced BS to retina

Question 28

Why does light move slower through the retina

Answer 28

increased density

Question 29

What determines degree of refraction

Answer 29

difference between two media

Question 30

How much refraction is needed for straight light rays

Answer 30

less

Question 31

Describe the lens when looking at distant objects

Answer 31

flattened, weak

Question 32

Describe the lens when looking at closer objects

Answer 32

rounded, strong

Question 33

Descirbe the ciliary muscle when looking on distant objects

Answer 33

relaxed

Question 34

What is the effect of rounding the lens

Answer 34

increases refractive power to focus closer objects

Question 35

Name some problems with focusing

Answer 35

hyperopia, myopia, presbyopia

Question 36

Describe hyperopia

Answer 36

far sightedness, not enough refraction

Question 37

How is hyperopia corrected

Answer 37

convex lens - increases refraction

Question 38

Describe myopia

Answer 38

short sightedness, long eyeball, more refraction

Question 39

What is presbyopia

Answer 39

loss of accommodation with ages - affects lens

Question 40

What regulates light levels

Answer 40

iris

Question 41

What constricts pupils

Answer 41

smooth circular msucle

Question 42

What dilates pupils

Answer 42

smooth radial muscle

Question 43

What innervates the muscles of the pupil

Answer 43

autonomic nervous system

Question 44

Which muscles in the eye does the parasympathetic nervous system innervate

Answer 44

inner circular muscles

Question 45

What is the effect of parasympathetic NS on the pupil

Answer 45

constriction

Question 46

What muscles of the eye does the sympathetic NS innervate

Answer 46

outer radial muscles

Question 47

What is the function of the pupillary light reflex

Answer 47

enables us to adjust to changes in light intensity