Ch 2 review

Question 1

Pupil

Answer 1

opening at the front of the eye where light passes through

Question 2

Iris

Answer 2

-colored part of the eye
-iris will constrict or dilate in order to let in more or less light

Question 3

cornea

Answer 3

-transparent covering of the front of the eye
-accounts for ~80% of focus power

Question 4

Lens

Answer 4

-light entering the eye is reversed, inverted, then focused onto the back of the eye
-focusing of near and distal vision
-~20% of focusing power

Question 5

difference between cornea and lens

Answer 5

lens can change shape (accommodate) to adjust lights focus, while cornea can not change shape

Question 6

ciliary muscles

Answer 6

change curvature of the lens

Question 7

increase in curvature…

Answer 7

increase ability to bend light, which increases focusing power

Question 8

near point

Answer 8

lens can no longer adjust in close objects

Question 9

Myopia

Answer 9

-nearsightedness
-image is focused in front of the retina making it harder to see distant objects clearly

Question 10

Vitreous humor

Answer 10

gel-like fluid that fills the center of the eye

Question 11

retina

Answer 11

-located in the back of the eye
-organized in layers and networks of neurons that convert the energy from light waves into neural signals

Question 12

photoreceptors

Answer 12

-visual receptor cells that are sensitive to light
-composed of opsin and retinal

Question 13

Rods

Answer 13

-sensitivity to light contrasts
-specialized for low light environments
-become more sensitive in the dark

Question 14

Cones

Answer 14

-much less
-sensitivity to color contrasts
-specialized for dealing with bright, colorful stimuli

Question 15

Fovea

Answer 15

-small area near the center of the retina that is packed with cones and has no rods
-sharpest vision in this area

Question 16

Blind spot

Answer 16

-region where optic nerve leave the eye
-no photoreceptors located here

Question 17

Visual process in the brain

Answer 17

half the fibers from each retina travel and remain on that side of the brain and the other half cross at the optic chiasma and all fibers end up in the primary visual cortex

Question 18

light energy from the eye travels to the

Answer 18

lateral geniculate nucleus in the thalamus where more neural processes take place

Question 19

Dark adaptation

Answer 19

process of increasing sensitivity in the dark and adjusting to dim levels of illumination

Question 20

Spectral sensitivity

Answer 20

-rods and cones are sensitive to different waves of light
-threshold for light is lowest in the middle of the spectrum

Question 21

Trichromatic theory

Answer 21

-The human eye contains three types of color receptors (red, green, blue)
-when one or more not present, colorblindness occurs

Question 22

The neuro

Answer 22

receive nerve impulses and release communications to stimulate neurons at the opposite end

Question 23

dendrites

Answer 23

receive nerve impulses and pass the information to the soma where the signal integrates

Question 24

soma

Answer 24

transmits integrated info along the axon that allows nerve impulses to pass

Question 25

axon

Answer 25

passes nerve impulses toward the terminal buttons that allow stimulation of nearby glands, muscles, and other neurons

Question 26

sensory neurons

Answer 26

carry nerve impulses away from sense receptors toward the nervous system

Question 27

moto neurons

Answer 27

carry nerve impulses away from the nervous system toward muscles and glands

Question 28

interneurons

Answer 28

relay nerve impulses between neurons

Question 29

glial cells

Answer 29

-surround neurons to hold in place -facilitate transmission of nerve impulses -remove corrupted neurons -protect brain from foreign substances -produce myelin sheath

Question 29

myelin sheath

Answer 29

insulating covor for axons

Question 30

Action potentials

Answer 30

-nerve impulses transmit information by means of electrochemical signals -excitatory or inhibitory

Question 31

excitatory input

Answer 31

increase the likelihood of an action potential release

Question 32

inhibitory input

Answer 32

decrease the likelihood of an action potential release

Question 33

phenomenon of action potentials

Answer 33

all or nothing principle

Question 34

absolute refractory period

Answer 34

no other action potential may pass through

Question 35

relative refractory period

Answer 35

an action potential may pass but needs additional activation to get to the baseline

Question 36

convergence

Answer 36

occurs when multiple signals synapse onto a single cell

Question 37

do more rods or cones converge on a single ganglion cell

Answer 37

more rods

Question 38

rods result in better

Answer 38

sensitivity but poor acuity

Question 39

cones result in better

Answer 39

detail but low sensitivity