Vision

Question 1

Cornea

Answer 1

clear, dome structure that allows light to enter

Question 2

Pupil

Answer 2

light passes through this gap in the Iris

Question 3

Iris

Answer 3

contractile muscles regulate pupil size

Question 4

Lens

Answer 4

behind the Iris, focusing light – creating focal point at the Fovea

Question 5

Optic Nerve

Answer 5

retina detects image, sent down optic nerve to the brain via a neural impulse

Question 6

Retinal Cells – RODS and CONES

Answer 6

• • light absorbing cells, responsible or transduction of light energy (photons) into an electrical signal
• • contain mitochondria and a nucleus
• • synapse is oriented toward the front of the eye to transduce signal
• • membrane shelves lined with Rhodopsin in the back of the eye

RODS: shadows

• • single rhodopsin pigment (no color detection)
• • low sensitivity to detail
• • permit night vision

CONES: colors

• • 3 rhodopsin pigments
• • sensitive to color and detail
• • best in bright light
• • concentrated at the fovea

Question 7

Retinal Cells – other signal transduction cells

Answer 7

BIPOLAR CELLS:

• • direct input from rods/cones
• • highlights gradients
• • synapse with ganglion cells

GANGLION CELLS:
– receives information from many cells and groups them together to form the optic nerve

AMACRINE CELLS:
– edge detection and contrasts, fine tuning visual image

Question 8

Visual Pathway

Answer 8

LEFT visual field perceived by RIGHT half of retina
RIGHT visual field perceived by LEFT half of retina

NASAL FIBERS reach the optic chiasm and cross over
TEMPORAL FIBERS remain on their respective sides

LEFT visual information will be transmitted to the LEFT side of the brain – the RIGHT visual field

RIGHT visual information will be transmitted to the RIGHT side of the brain – the LEFT visual field

visual information sent to the LATERAL GENICULATE NUCLEUS (Thalamus) and then to the VISUAL CORTEX (Occipital Lobe) and the SUPERIOR COLLICULUS (Midbrain)

Question 9

Parallel Processing

Answer 9

ability to identify characteristics and apply

• • apply characteristics to a memory
• • recall a word to describe the object

Question 10

Feature Detection

Answer 10

recognition of features

• • identify an object in a visual field
• • automatically filter by certain features

Question 11

Signal Detection Theory

Answer 11

the perception of stimuli can be affected by non-sensory factors such as memory, experiences, motives, and expectations.
– Our perception of the same stimuli changes depending on internal and external contexts