Chapter 2: Senses and Perception

Question 1

what is transduction?

Answer 1

the process of turning stimuli into electrical signals
- executed by sensory organs

Question 2

what is the process of sense and perception?

Answer 2

stimuli –> transduction –> transmission –> analysis and integration

Question 3

what is the function of the iris?

Answer 3

regulates light entering the eye by changing the size of the pupil

Question 4

what is the function of the cornea and lens?

Answer 4

focus the light onto the retina

Question 5

what is the function of the retina?

Answer 5

maps visual input as 2D reversed image

Question 6

what are photoreceptors?

Answer 6

• rods and cones
• sites of transduction

Question 7

what are rods?

Answer 7

• long cylindrical outer segment with many discs
• more sensitive to light, allow for vision in darkness (scotopic)
• absent in fovea
• 92 million in each retina

Question 8

what are cones?

Answer 8

• short tapering outer segment with fewer discs
• less sensitive to light, active in light conditions (photopic_
• concentrated in fovea
• 5 million

Question 9

what are interneurons?

Answer 9

• amacrine, bipolar, horizontal cells
• process information from photoreceptors and relay to the ganglion cells

Question 10

what are ganglion cells?

Answer 10

process and relay information from photoreceptors through the optic nerve
- have receptive fields, form a 2D representation of visual scene

Question 11

what is the fovea?

Answer 11

densely packed cones (red+green) resolve fine details

Question 12

what is the macula?

Answer 12

each ganglion cell receives input from only one (or few) cones, resolve details, critical for reading +driving

Question 13

what does the receptive field of a ganglion cell consist of?

Answer 13

a center area with a surrounding donut shaped area, which are antagonistic (when one is active it inhibits the other)