Anatomy of the Eye

Question 1

what is the sclera?

Answer 1

white, tough wall of the eye (poorly innervated)

Question 2

what is the conjunctiva?

Answer 2

thin lining over the sclera and the inside of the eyelids (inflammation = conjunctivitis)

Question 3

what is the cornea?

Answer 3

clear continuation of the sclera over the iris and pupil

Question 4

describe the corneal reflex

Answer 4

CN V feels -> CN VII closes eye

Question 5

what is the iris?

Answer 5

composed of muscles which constrict or dilate the pupil
(coloured part)

Question 6

what is the macula?

Answer 6

• part of the retina which is most sensitive and has the least number of vessels
• responsible for central vision

Question 7

what is the fovea?

Answer 7

2mm pit in the macula where all retinal layers are shifted away so that the image is received by the photoreceptors with the least amount of distortion

Question 8

what is the pupil?

Answer 8

a hole in the iris, whose size is controlled by the iris muscles

Question 9

what is the optic disc?

Answer 9

the blind spot
- contains no photoreceptors
- passageway for optic nerve and vessels

Question 10

where are photoreceptors located?

Answer 10

deepest layer of retina

Question 11

where are bipolar cells located?

Answer 11

intermediate layer of retina

Question 12

the superficial layer of the retina is made up of ____

Answer 12

ganglion cells

Question 13

axons of ganglion cells in the retina make up the ____

Answer 13

CN II: optic nerve

Question 14

In the retina, light has to travel through ____ to reach the ____

Answer 14

all layers
photoreceptors

Question 15

function of horizontal and amacrine cells

Answer 15

allow communication between photoreceptors & bipolar cells (convergence), and bipolar cells & photoreceptors (lateral inhibition)

Question 16

what are the 2 types of photoreceptors?

Answer 16

rods
cones

Question 17

functions of rods

Answer 17

night vision

Question 18

function of cones

Answer 18

day vision/colour vision

Question 19

sensitivity to light in rods

Answer 19

high sensitivity (1000x), single photon detection (less detailed)

Question 20

photopigmentation of rods

Answer 20

• high photopigment, capture more light
• 1 type of photopigment

Question 21

rods saturate in ____

Answer 21

day light

Question 22

visual acuity of rods

Answer 22

low

Question 23

rods in the fovea

Answer 23

not present

Question 24

sensitivity to light in cones

Answer 24

low

Question 25

photopigmentation of cones

Answer 25

• low photopigment
• 3 types: blue, red, green

Question 26

visual acuity of cones

Answer 26

high

Question 27

cones in the fovea

Answer 27

concentrated in fovea

Question 28

describe the photoreceptors in the peripheral retina

Answer 28

• high ratio of photoreceptors to ganglion cells
• rods > cones
• high sensitivity to light

Question 29

describe the photoreceptors in the central retina

Answer 29

• lowest ratio of cones to ganglion cells (almost 1:1)
• no rods

Question 30

what part of the retina sees the least colour?

Answer 30

peripheral

Question 31

macular degeneration involves degeneration of the ____

Answer 31

central retina (macula)

Question 32

retinitis pigmentosa involves degeneration of the ____

Answer 32

peripheral retina