lecture 20: eye

Question 1

for pupillary light reflex, what CN is it afferent for?

Answer 1

CN II - carries sensory input from the retina when light enters the eye

Question 2

for pupillary light reflex, what CN is it efferent for?

Answer 2

CN III - mediates the motor responses causing pupillary constriction via the parasympathetic fibers

Question 3

what is the edinger-westphal nucleus?

Answer 3

the parasympathetic nucleus of oculomotor nerve

Question 4

why do both pupils constrict?

Answer 4

bilateral connections between the pretectal area and the Edinger-Wesphal nucleus result in the constriction in the other eye

Question 5

opening where the light enters the eye

Answer 5

pupil

Question 6

colored

Answer 6

iris

Question 7

white

Answer 7

sclera

Question 8

glassy transparent external surface of the eye

Answer 8

cornea

Question 9

membrane that folds back from the inside of the eyelid and attaches to the sclera

Answer 9

conjunctiva

Question 10

three pairs that move the eye in orbit

Answer 10

extraocular muscles

Question 11

bundle of axons from the retina

Answer 11

optic nerve

Question 12

what are the three layers of tissues from most superficial to innermost layer?

Answer 12

sclera and cornea

choroid

retina

Question 13

vascular layer of tissue between the retina and sclera and ciliary body

Answer 13

choroid

Question 14

ring shaped tissues that encircles the lens

Answer 14

ciliary body

Question 15

what does the retina do?

Answer 15

receives and processes visual information which is then sent to the brain for interpretation

Question 16

what contains photoreceptor cells and what do they do?

Answer 16

the retina

photoreceptor cells detect light and convert into electrical signals (phototransduction)

Question 17

what are lens?

Answer 17

involved in forming sharp images of near objects (closer than 9m)

Question 18

what has the highest visual acuity and smallest visual field?

Answer 18

fovea

Question 19

what is the blind spot?

Answer 19

optic disc

Question 20

what is vitreous humor and what structure is it a part of?

Answer 20

jelly like fluid

part of the lens

Question 21

what are the extraocular muscles?

Answer 21

superior
inferior
medial
lateral

Question 22

where do the oblique muscles attach?

Answer 22

to the posterior half of the eyeball

Question 23

what does the superior oblique do when the eye is looking STRAIGHT FORWARD or ABDUCTED?

Answer 23

rotates the eye upward

Question 24

what does the superior oblique do when the eye is ADDUCTED?

Answer 24

superior oblique moves the eye downward

Question 25

when ADDUCTED, what does the inferior oblique do?

Answer 25

inferior oblique moves the eye upward

Question 26

what are the five types of neurons in the retina?

Answer 26

photoreceptors bipolar cells ganglion cells amacrine cells horizontal cells

Question 27

what are the only light-sensitive cells in the retina?

Answer 27

photoreceptors (rods and cones)

Question 28

what are the graded membrane potentials for the photoreceptors?

Answer 28

cones receptors (color) rod receptors (black and white)

Question 29

what is the only source of output from the retina?

Answer 29

optic nerve

Question 30

what are the only retinal cells that fire action potentials (first order neurons)?

Answer 30

ganglion cells