Ch. 10.1 The Retina Transduces Light into Neuronal Activity

Question 1

What is visible light?

Answer 1

It is a narrow band of electromagnetic radiation.

Question 2

What is a wavelength?

Answer 2

The distance between two peaks in a repeated stimulus such as a wave, light, or sound.

Question 3

What is a cornea

Answer 3

The outer layer of the eye

Question 3

What is the lens?

Answer 3

A structure in the eye that help focus an image on the retina.

Question 4

What is refraction?

Answer 4

The bending of light rays due to a change in density of a medium (air to the cornea or lens)

Question 5

What is the name of the muscles which adjust the shape of the eye lens in order to focus?

Answer 5

Ciliary muscles

Question 6

The process of focusing by the ciliary muscles and the lens to form a sharp image on the retina.

Answer 6

Accommodation

Question 7

What controls the amount of light let into the eye?

Answer 7

The pupil (black part)

Question 8

What muscles control the rotational movements of the eye?

Answer 8

Extraocular muscles

Question 9

Where does the first stages of visual information processing occur?

Answer 9

The retina

Question 10

What are the receptor cells that detect light called?

Answer 10

photoreceptors

Question 11

What are the two kinds of photoreceptor cells?

Answer 11

1. rods (long and narrow and most active at low levels of light)
2. cones (responsible for color vision)

Question 12

What is a bipolar cell?

Answer 12

A class of interneurons of the retina that receive information from rods and cones and pass the information to retinal ganglion cells.

Question 13

What are ganglion cells?

Answer 13

A class of cells in the retina whose axons form the optic nerve.

Question 14

What is the optic nerve?

Answer 14

Cranial nerve ll; the collection of ganglion cell axons that extended from the retina to the optic chiasm.

Question 15

Do rod and cone photoreceptors release neurotransmitter molecules?

Answer 15

Yes

Question 16

What are horizontal cells?

Answer 16

Specialized neurons that contact both the receptor cells and the bipolar cells.

Question 17

What are amacrine cells

Answer 17

Specialized neurons that contact both the bipolar cells and the ganglion cells.

Question 18

Rods, cones, bipolar cells, horizontal cells and ganglion cells : of these which produce action potentials or graded local potentials

Answer 18

Rods, cones, bipolar cells, horizontal cells produce graded local potentials (using neurotransmitters)
Ganglion cells produce action potentials

Question 19

How do photoreceptors transduce light into chemical reactions?

Answer 19

1. The photons that strike the discs are captured by special photopigment receptor molecules (called rhodopsin) in the rods.
2. RETINAL dissociates from the opsin molecule revealing an enzymatic site.
3. a bunch of chemical stuff happens resulting in hyperpolarization

Question 20

Where are photons detected?

Answer 20

the rods and cones

Question 21

What is a photon?

Answer 21

A quantum of electromagnetic energy in the range of wavelengths we call light

Question 22

The rod and cone photopigments in the eye consist of two parts

Answer 22

A. RETINAL
B. opsin

Question 23

What is the scotopic system

Answer 23

A system in the retina that operates at low levels of light and involves the rods. It does not respond to colors

Question 24

What is the photopic system?

Answer 24

A system in the retina that operates at high levels of light, show sensitivity to color, and involves the cones.