vision and the eye

Question 1

what is the stimulus for vision?

Answer 1

electromagnetic energy or light waves

Question 2

what is the lens?

Answer 2

elastic structure that changes to help focus

Question 3

when the lens becomes thinner, it is focusing on objects that are?

Answer 3

far away/more distant

Question 4

what is the retina?

Answer 4

a multi-layered structure at the back of the eye that contains light-sensitive photoreceptors

Question 5

what is the function of the retina?

Answer 5

light-sensitive photoreceptors transduce light into electrical impulses

Question 6

what is the cornea?

Answer 6

transparent protective structure at the front of the eye

Question 7

what is the pupil?

Answer 7

and adjustable opening behind the cornea

Question 8

what is the function of the pupil?

Answer 8

controls the amount of light that enters the eye through iris muscles

Question 9

when pupils dilate, they? when pupils constrict, they?

Answer 9

get bigger; get smaller

Question 10

what does your ability to see clearly depend on?

Answer 10

being able to accurately focus an image directly into your retina

Question 11

what is myopia? people with myopia have difficulty seeing?

Answer 11

nearsightedness; difficulty seeing far away objects

Question 12

what is hyperopia? people with hyperopia have difficulty seeing?

Answer 12

farsightedness; difficulty seeing up close objects

Question 13

what are the two types of light sensitive cells found in the retina?

Answer 13

rods and cones

Question 14

what are rods?

Answer 14

photoreceptors that contribute to black and white vision and are more sensitive to light then cones

Question 15

what is the fovea?

Answer 15

the center of the retina that increases in concentration through the periphery of the retina

Question 16

what are cones?

Answer 16

contribute to perception of color and detail and functions best in high illumination

Question 17

what does the fovea only contain?

Answer 17

cones!

Question 18

what are bipolar cells?

Answer 18

receive signals from rods and cones to form a synapse with them

Question 19

which light sensitive cells is typically connected to bipolar cells?

Answer 19

rods! greater sensitivity to light

Question 20

what do the ganglion cells do?

Answer 20

form a synapse with the bipolar cell

Question 21

the axons of the ganglion cell form the?

Answer 21

optic nerve

Question 22

what is the pathway of transduction?

Answer 22

rods/cones –> bipolar cells –> ganglion cells –> optic nerve

Question 23

what cells modulate the signals of transduction?

Answer 23

horizontal and amacrine

Question 24

what are photopigments?

Answer 24

protein molecules in the retina

Question 25

what is the reaction of photopigments critical for?

Answer 25

visual transduction

Question 26

photopigments undergo what type of reaction to transduce a light signal into neural code?

Answer 26

isomerization

Question 27

photopigment cells need time to?

Answer 27

regenerate

Question 28

what is the blind spot

Answer 28

axons that form the optic nerve create a blind spot with no photoreceptors

Question 29

what are dark adaptations?

Answer 29

the progressive improvement of brightness sensitivity in low lighting conditions

Question 30

the process of dark adaptation revolves around?

Answer 30

changes in the proportion of photopigments that are ready to transduce light to used photopigments in the process of regenerating

Question 31

do rods or cones take longer to regenerate?

Answer 31

rods

Question 32

what is pigment bleaching?

Answer 32

being temporarily 'blinded' by a bright light because the photopigment supply is depleted and must regenerate before transduction can occur again

Question 33

how many types of photopigment do rods have?

Answer 33

one

Question 34

what color of photopigment are rods most sensitive to?

Answer 34

blue (shortest wavelength)