Verified Test Bank Transduction And Transmission In The Ch22

Chapter 22: Transduction and Transmission in the Retina

Test Bank

Type: multiple choice question

Title: Chapter 22 Question 01

1. What is one reason we cannot clearly read text that we are not focused on?

Feedback: Subhead: The Vertebrate Eye

Learning Objective: Explain why vision in vertebrates is not uniformly detailed across the eye.

Bloom’s Level: 2. Understanding

a. Cones, which contribute to color vision, are more concentrated in the fovea.

b. Light is not projected fully on the periphery of vision, making it difficult to see text.

c. Photoreceptor density falls off sharply in the periphery of vision, making it difficult to distinguish patterns like text.

d. Rods, which enable us to distinguish patterns of text, are highly concentrated in the fovea.

e. Our perception of peripheral images is not as detailed as foveal images because of higher-order processing.

Type: multiple choice question

Title: Chapter 22 Question 02

2. Density and connectivity of rods is highest in the periphery, just outside of the fovea. What is one consequence of this configuration?

Feedback: Subhead: The Vertebrate Eye

Learning Objective: Explain why vision in vertebrates is not uniformly detailed across the eye.

Bloom’s Level: 2. Understanding

a. Color vision is most clear in the periphery.

b. Vision in dim light is most clear in the periphery.

c. Vision in dim light is most clear in the fovea.

d. Color vision is most clear in the fovea.

e. Color vision is just as clear in the fovea as in the periphery.

Type: multiple choice question

Title: Chapter 22 Question 03

3. Which type of cell is chiefly responsible for responding to illumination, without consideration for color?

Feedback: Subhead: The Vertebrate Eye

Learning Objective: Describe the functions of the five main classes of retinal neurons.

Bloom’s Level: 1. Remembering

a. Rods

b. Amacrine cells

c. Bipolar cells

d. Cones

e. Horizontal cells

Type: multiple choice question

Title: Chapter 22 Question 04

4. Amacrine type II (AII) cells primarily synapse with

Feedback: Subhead: The Vertebrate Eye

Learning Objective: Describe the synaptic organization of the rod and cone pathways in the retina.

Bloom’s Level: 1. Remembering

a. D bipolar cells.

b. H bipolar cells.

c. ganglion cells.

d. D bipolar cells and H bipolar cells.

e. horizontal cells.

Type: multiple choice question

Title: Chapter 22 Question 05

5. Photoreceptors, horizontal, and bipolar cells generate _______ ganglion cells and amacrine cells generate _______.

Feedback: Subhead: The Vertebrate Eye

Learning Objective: Describe the synaptic organization of the rod and cone pathways in the retina.

Bloom’s Level: 1. Remembering

a. action potentials; action potentials

b. graded local potentials; graded local potentials

c. action potentials; graded local potentials

d. graded local potentials; calcium cascades

e. graded local potentials; action potentials

Type: multiple choice question

Title: Chapter 22 Question 06

6. _______ are found in the _______ layer of the retina.

Feedback: Subhead: The Vertebrate Eye

Learning Objective: Describe the functions of the five main classes of retinal neurons.

Bloom’s Level: 1. Remembering

a. Ganglion cells, deepest

b. Bipolar cells, deepest

c. Horizontal cells, middle

d. Amacrine cells, outermost

e. Photoreceptors, deepest

Type: multiple choice question

Title: Chapter 22 Question 07

7._______ cones generally outnumber _______ cones in humans.

Feedback: Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Define the three types of cones that contribute to color vision in humans.

Bloom’s Level: 1. Remembering

a. Long (L) and short (S); medium (M)

b. Long (L); medium (M) and short (S)

c. Medium and short (S); long (L)

d. Medium; long (L) and short (S)

e. Long (L) and medium (M); short (S)

Type: multiple choice question

Title: Chapter 22 Question 08

8. The names for the different types of cones (long, short, and medium) refer to

Feedback: Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Define the three types of cones that contribute to color vision in humans.

Bloom’s Level: 2. Understanding

a. the wavelengths of light they absorb.

b. the length of their bodies.

c. the time it takes for them to fire action potentials.

d. the length of their axons.

e. how long they live.

Type: multiple choice question

Title: Chapter 22 Question 09

9. Pigments that are responsive to light are found in the _______ of the photoreceptor.

Feedback: Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Describe the three principal features of photoreceptor structure.

Bloom’s Level: 1. Remembering

a. dendrites

b. outer segment

c. inner segment

d. synaptic terminal

e. axon

Type: multiple choice question

Title: Chapter 22 Question 10

10. Pigments in cones are found _______ the cell membrane and pigments in rods are found _______ the cell membrane.

Feedback: Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Describe the three principal features of photoreceptor structure.

Bloom’s Level: 1. Remembering

a. inside; continuous with

b. continuous with; outside

c. inside; inside

d. continuous with; inside

e. outside; continuous with

Type: multiple choice question

Title: Chapter 22 Question 11

11. While stargazing one night, you notice that a particular star appears to vanish whenever you move your eyes to a specific part of the sky. Why might this occur?

Feedback: Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Explain why there are two blind spots in the human eye.

Bloom’s Level: 3. Applying

a. The light of the star is too dim to be detected by certain rods.

b. The light of the star is being projected onto the fovea, where there are too few rods to detect it.

c. The light of the star is being projected onto the periphery, where there are too few cones to detect it.

d. The light of the star is producing varying quanta of photons, which rods cannot reliably detect.

e. The light of the star is too dim to be detected by certain cones.

Type: multiple choice question

Title: Chapter 22 Question 12

12. Under certain conditions, visual stimuli, even in bright light, can seem to disappear from our perception. What is one potential cause of this phenomenon in healthy human eyes?

Feedback: Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Explain why there are two blind spots in the human eye.

Bloom’s Level: 2. Understanding

a. Light can be completely blocked from reaching the retina if pupils constrict too far.

b. Corneas may reflect only part of an image to the retina.

c. There are no photoreceptors at the location where optic nerve fibers leave the eye, which causes a blind spot.

d. In certain parts of the retina, photoreceptors may “cancel” each other out so no signals are sent.

e. This phenomenon is a product of higher-order perception and does not involve the retina.

Type: multiple choice question

Title: Chapter 22 Question 13

13. You train a macaque to respond to the presentation of a red circle by ringing a bell, after which she is presented with a treat. One evening, the power goes out, but you decide to continue your training with the macaque using the waning sunlight. To your surprise, the macaque seems to be unable to respond properly to the red circle after about an hour. What is one explanation for the macaque’s regression?

Feedback: Subhead: Visual Pigments

Learning Objective: Explain why night-vision in humans is color-blind.

Bloom’s Level: 3. Applying

a. The repeated training has made the red stimulus too ambiguous to the macaque’s perception.

b. The waning light has made the red stimulus appear brighter due to increased cone activation.

c. The waning light has made the red stimulus less prominent due to increased rod activation.

d. The waning light has made the red stimulus less prominent due to decreased cone activation.

e. The repeated training has made the red stimulus appear green to the macaque.

Type: multiple choice question

Title: Chapter 22 Question 14

14. Retinal plays a key role in preventing rhodopsin from

Feedback: Subhead: Visual Pigments

Learning Objective: Describe the basic structure of rhodopsin.

Bloom’s Level: 2. Understanding

a. undergoing thermal isomerization.

b. responding too readily to photons.

c. undergoing isomerization in the presence of one photon of light.

d. changing structure due to being exposed to light.

e. opening calcium channels in the photoreceptor.

Type: multiple choice question

Title: Chapter 22 Question 15

15. During transduction, the α subunit of the associated G protein binds to which part of the photoreceptor?

Feedback: Subhead: Visual Pigments

Learning Objective: Describe the basic structure of rhodopsin.

Bloom’s Level: 1. Remembering

a. Chromosphere

b. Amino terminus

c. Opsin

d. Retinal subunit

e. Carboxy terminus

Type: multiple choice question

Title: Chapter 22 Question 16

16. Within picoseconds of a photon being absorbed by rhodopsin,

Feedback: Subhead: Visual Pigments

Learning Objective: Discuss the role that rhodopsin plays in transduction.

Bloom’s Level: 1. Remembering

a. retinal undergoes photoisomerization, shifting from 11-cis retinal to all-trans retinal.

b. opsin changes configuration to metarhodopsin II.

c. rhodopsin is regenerated and able to bind photons again.

d. the membrane potential of the photoreceptor is altered.

e. the outer segment of the photoreceptor separates from the inner segment.

Type: multiple choice question

Title: Chapter 22 Question 17

17. You are tracking the concentration of rhodopsin in a culture of rod cells. Following a flash of light, you return the culture to complete darkness. How long will it take for the concentration of rhodopsin to return to the state observed before the flash?

Feedback: Subhead: Visual Pigments

Learning Objective: Discuss the role that rhodopsin plays in transduction.

Bloom’s Level: 3. Applying

a. Seconds

b. Picoseconds

c. Minutes

d. Up to an hour

e. Microseconds

Type: multiple choice question

Title: Chapter 22 Question 18

18. In most invertebrates, light _______ photoreceptors; in most vertebrates, light _______ photoreceptors.

Feedback: Subhead: Transduction

Learning Objective: Describe, in general terms, how light produces electrical signals in the retina.

Bloom’s Level: 1. Remembering

a. hyperpolarizes; depolarizes

b. hyperpolarizes; hyperpolarizes

c. depolarizes; depolarizes

d. depolarizes; hyperpolarizes

e. depolarizes and hyperpolarizes; hyperpolarizes

Type: multiple choice question

Title: Chapter 22 Question 19

19. Rhodopsin responds to light by causing _______ channels to close, halting the constant influx of these ions into photoreceptors that occurs in darkness.

Feedback: Subhead: Transduction

Learning Objective: Describe, in general terms, how light produces electrical signals in the retina.

Bloom’s Level: 1. Remembering

a. calcium and sodium

b. potassium and calcium

c. sodium and chlorine

d. chlorine and calcium

e. potassium and sodium

Type: multiple choice question

Title: Chapter 22 Question 20

20. Cyclic guanosine monophosphate (cGMP) found in the cytoplasm of photoreceptors is usually found in

Feedback: Subhead: Transduction

Learning Objective: Discuss how cytoplasmic cGMP influences the membrane potential of photoreceptors.

Bloom’s Level: 1. Remembering

a. high quantities in the dark, where its presence keeps ion channels open.

b. low quantities in the dark, during which ion channels are closed.

c. high quantities after the absorption of photons, which causes ion channels to open.

d. low quantities after the absorption of photons, which causes ion channels to open.

e. high quantities after the absorption of photons, which causes ion channels to close.

Type: multiple choice question

Title: Chapter 22 Question 21

21. Ion channels on photoreceptors that open or close due to cyclic guanosine monophosphate (cGMP) are responsible for maintaining the photoreceptor’s resting membrane potential, which is usually about

Feedback: Subhead: Transduction

Learning Objective: Discuss how cytoplasmic cGMP influences the membrane potential of photoreceptors.

Bloom’s Level: 1. Remembering

a. -80 mV, until it is depolarized by light.

b. -40 mV, until it is depolarized by light.

c. -80 mV, until it is hyperpolarized by light.

d. -40 mV, until it is hyperpolarized by light.

e. -20 mV, until it is hyperpolarized by light.

Type: multiple choice question

Title: Chapter 22 Question 22

22. The hydrolyzation of cyclic guanosine monophosphate (cGMP) is caused by the interaction between transducin and which molecule?

Feedback: Subhead: Transduction

Learning Objective: Describe how the G protein transducin is involved in transduction.

Bloom’s Level: 1. Remembering

a. Metarhodopsin I

b. Metarhodopsin II

c. Thodopsin

d. 11-cis retinal

e. All-trans retinal

Type: multiple choice question

Title: Chapter 22 Question 23

23. Reduced concentrations of the molecule cGMP causes channels in the cell membrane of photoreceptors to _______, which _______ the cell.

Feedback: Subhead: Transduction

Learning Objective: Describe how the G protein transducin is involved in transduction.

Bloom’s Level: 2. Understanding

a. open; hyperpolarizes

b. open; depolarizes

c. form; hyperpolarizes

d. close; hyperpolarizes

e. close; depolarizes

Type: multiple choice question

Title: Chapter 22 Question 24

24. During sustained illumination, a decrease in intracellular _______ prevents all nucleotide gated channels in photoreceptors from closing.

Feedback: Subhead: Transduction

Learning Objective: Give three ways by which a fall in intracellular calcium affects adaptation of photoreceptors to light.

Bloom’s Level: 1. Remembering

a. potassium

b. calcium

c. sodium

d. chlorine

e. carbon

Type: multiple choice question

Title: Chapter 22 Question 25

25. Dark adaptation takes much longer than light adaptation. What is one reason this is the case?

Feedback: Subhead: Transduction

Learning Objective: Give three ways by which a fall in intracellular calcium affects adaptation of photoreceptors to light.

Bloom’s Level: 3. Applying

a. Light adaptation involves the release of potassium, which is rapidly pumped through ion channels.

b. Dark adaptation is limited by the number of rods, which is much lower than the number of cones.

c. Light adaptation is handled by many photoreceptors while dark adaptation is handled by only a few.

d. Dark adaptation takes longer because fewer photons of light reach the retina.

e. Dark adaptation is limited by the recovery of pigment molecules in photoreceptors, which takes a long time.

Type: multiple choice question

Title: Chapter 22 Question 26

26. What do cone and rod pigments have in common?

Feedback: Subhead: Transduction

Learning Objective: Explain what accounts for the ability of different visual pigments to trap specific wavelengths of light preferentially.

Bloom’s Level: 1. Remembering

a. They are all found in extracellular space.

b. They are all made up of the same amino acids.

c. They all contain 11-cis retinal.

d. They are all equally sensitive to light.

e. They are all found in the inner segment.

Type: multiple choice question

Title: Chapter 22 Question 27

27. Why do some photoreceptors respond to blue light, while others respond to red or green?

Feedback: Subhead: Transduction

Learning Objective: Explain what accounts for the ability of different visual pigments to trap specific wavelengths of light preferentially.

Bloom’s Level: 1. Remembering

a. There are differences in the amino acid sequences for their opsin proteins.

b. There are differences in the amino acid sequences for their 11-cis retinal.

c. Photoreceptors for different colors are found at different depths within the retina.

d. Photoreceptors for different colors utilize center-surround organization in different ways.

e. Photoreceptors for different colors regenerate at different rates, leading to the perception of color.

Type: multiple choice question

Title: Chapter 22 Question 28

28. Through inheritance, Jorge does not possess long (L) or medium (M) cones in his retina. Jorge’s vision is impacted in which way?

Feedback: Subhead: Transduction

Learning Objective: Explain what causes color blindness and give two examples of color blindness in humans.

Bloom’s Level: 3. Applying

a. He can only perceive shades of the color blue.

b. He can perceive shades of blue and green.

c. He cannot perceive any color.

d. He can perceive only shades of yellow and green.

e. He cannot see properly in the dark.

Type: multiple choice question

Title: Chapter 22 Question 29

29. Which statement about receptive fields is true?

Feedback: Subhead: Integration of Visual Inputs

Learning Objective: Define receptor field.

Bloom’s Level: 2. Understanding

a. Receptive fields are only found primates.

b. Receptive fields are only found in relation to rods.

c. Receptive fields come in only two varieties.

d. Receptive fields tell the brain about patterns of light and dark.

e. Receptive fields are only found in invertebrates.

Type: multiple choice question

Title: Chapter 22 Question 30

30. Cones in the fovea are clustered in hexagonal patterns (one center, six surround). Flashing a light on the central cone produces perception of

Feedback: Subhead: Integration of Visual Inputs

Learning Objective: Define receptor field.

Bloom’s Level: 2. Understanding

a. whichever color cone is in the center.

b. whichever color cone makes the majority of the surround.

c. a number of colors, depending on background color and cones in the surround.

d. a number of colors, depending on cones in the surround.

e. whichever color light is used on the center cone.

Type: multiple choice question

Title: Chapter 22 Question 31

31. Which of the following is true about the center-surround organization of receptive fields?

Feedback: Subhead: Integration of Visual Inputs

Learning Objective: Discuss two important features of the mammalian visual system that were revealed by Kuffler’s recordings of retinal ganglion cells.

Bloom’s Level: 1. Remembering

a. Illumination of both the center and the surround leads to an increase in cell activity in the same direction.

b. Illumination of both the center and the surround leads to a decrease in cell activity in the same direction.

c. Illumination of both the center and the surround leads to an antagonistic effect on cell activity, with one exciting the cell and the other inhibiting the cell.

d. Only illumination of the center of the receptive field has an effect on cell activity.

e. Only illumination of the surround of the receptive field has an effect on cell activity.

Type: multiple choice question

Title: Chapter 22 Question 32

32. Which of the following is true about horizontal cells?

Feedback: Subhead: Synaptic Organization of the Retina

Learning Objective: Describe how bipolar, horizontal, and amacrine cells are involved in signaling.

Bloom’s Level: 1. Remembering

a. Horizontal cells are connected to one another via gap junctions.

b. Horizontal cells do not synapse directly with photoreceptors.

c. Horizontal cells synapse directly with retinal ganglion cells.

d. Horizontal cells release glutamate.

e. Horizontal cells produce action potentials.

Type: multiple choice question

Title: Chapter 22 Question 33

33. Which type(s) of cell receive(s) input directly from cones?

Feedback: Subhead: Synaptic Organization of the Retina

Learning Objective: Describe how bipolar, horizontal, and amacrine cells are involved in signaling.

Bloom’s Level: 1. Remembering

a. Depolarizing bipolar cell

b. Hyperpolarizing bipolar cell

c. Both depolarizing and hyperpolarizing bipolar cells

d. Ganglion cell

e. Amacrine type II (AII) cell

Type: multiple choice question

Title: Chapter 22 Question 34

34. What is the primary neurotransmitter released by photoreceptors?

Feedback: Subhead: Synaptic Organization of the Retina

Learning Objective: Name the neurotransmitter released by photoreceptors and horizontal cells.

Bloom’s Level: 1. Remembering

a. Dopamine

b. Glycine

c. Glutamate

d. Acetylcholine

e. ℽ-aminobutyric acid (GABA)

Type: multiple choice question

Title: Chapter 22 Question 35

35. What is the primary neurotransmitter released by horizontal cells?

Feedback: Subhead: Synaptic Organization of the Retina

Learning Objective: Name the neurotransmitter released by photoreceptors and horizontal cells.

Bloom’s Level: 1. Remembering

a. Glutamate

b. Nitric oxide

c. ℽ-aminobutyric acid (GABA)

d. Glycine

e. Serotonin

Type: multiple choice question

Title: Chapter 22 Question 36

36. In response to light in the surround of their receptive fields, H bipolar cells are _______, while D bipolar cells are _______.

Feedback: Subhead: Synaptic Organization of the Retina

Learning Objective: Compare the receptive field organization and responses of hyperpolarizing (H) and depolarizing (D) bipolar cells.

Bloom’s Level: 1. Remembering

a. unaffected; hyperpolarized

b. depolarized; hyperpolarized

c. depolarized; depolarized

d. hyperpolarized; depolarized

e. hyperpolarized; unaffected

Type: multiple choice question

Title: Chapter 22 Question 37

37. Rods synapse with _______, which in turn synapse with _______.

Feedback: Subhead: Synaptic Organization of the Retina

Learning Objective: Compare the receptive field organization and responses of hyperpolarizing (H) and depolarizing (D) bipolar cells.

Bloom’s Level: 1. Remembering

a. hyperpolarizing (H) bipolar cells; amacrine type II (AII) amacrine cells

b. amacrine type II (AII) cells; depolarizing (D) bipolar cells

c. hyperpolarizing (H) bipolar cells; depolarizing (D) bipolar cells

d. depolarizing (D) bipolar cells; horizontal cells

e. depolarizing (D) bipolar cells; amacrine type II (AII) cells

Type: multiple choice question

Title: Chapter 22 Question 38

38. While watching the sun set in your garden, you notice that at first, the red-colored flowers are very vibrant compared to the blue flowers. However, as the sunlight begins to fade, you notice this reverses: the red flowers start to look dull and dark while the blue flowers look vibrant and bright. What is this phenomenon known as?

Feedback: Subhead: Synaptic Organization of the Retina

Learning Objective: Define the Purkinje effect.

Bloom’s Level: 3. Applying

a. Monochromacy

b. The Thatcher effect

c. Acute color blindness

d. The Purkinje effect

e. Protanopia

Type: multiple choice question

Title: Chapter 22 Question 39

39. Which ganglion cell type is most likely to respond to a moving black circle shown in the periphery of vision?

Feedback: Subhead: Receptive Fields and Projections of Ganglion Cells

Learning Objective: Summarize the characteristics of the three principal categories of retinal ganglion cells.

Bloom’s Level: 3. Applying

a. Koniocellular (K)

b. Parvocellular (P)

c. Amacrine (A)

d. Long (L)

e. Magnocellular (M)

Type: multiple choice question

Title: Chapter 22 Question 40

40. Specialized cells called ______ can respond to light directly, rather than only through a signaling cascade from rods and cones.

Feedback: Subhead: Receptive Fields and Projections of Ganglion Cells

Learning Objective: Define intrinsically photosensitive retinal ganglion cells (ipRGCs) and explain what role they play in the visual system.

Bloom’s Level: 1. Remembering

a. parvocellular rods

b. midget ganglion cells

c. melanopsin sensitive bipolar cells

d. retinal photosensitive horizontal cells

e. intrinsically photosensitive retinal ganglion cells

Type: multiple choice question

Title: Chapter 22 Question 41

41. A certain breed of mice is shown to be unable to regulate their sleep schedule in response to regular cycles of bright and dim light. What is one mechanism through which these mice could have obtained this deficiency?

Subhead; Receptive Fields and Projections of Ganglion Cells

Learning Objective: Define intrinsically photosensitive retinal ganglion cells (ipRGCs) and explain what role they play in the visual system.

Bloom’s Level: 3. Applying

a. The mice were bred without long (L) cones.

b. The mice were bred without rods.

c. The mice were bred without intrinsically photosensitive retinal ganglion cells.

d. The mice were bred without horizontal cells.

e. The mice were bred without the ability to produce retinal.

Type: essay/short answer question

Title: Chapter 22 Question 42

42. A friend is recounting a time when she was home and saw something move out of the “corner of her eye.” When she turned to look at, all she saw was her coat hanging on a hook. Your friend is convinced what she saw was not of this world. What could you tell your friend about our visual system to put your friend’s mind at ease?

Feedback: I might tell my friend that our visual acuity in the periphery of our vision is not very clear. This can cause objects that appear in the periphery to be fuzzy or ambiguous. What she saw was most likely just her coat, but the ambiguity of the object made her think it was moving or something else.

Subhead: The Vertebrate Eye

Learning Objective: Explain why vision in vertebrates is not uniformly detailed across the eye.

Bloom’s Level: 4. Analyzing

Type: essay/short answer question

Title: Chapter 22 Question 43

43. Photoreceptors synapse with other cell types before their signals reach the optic nerve. Describe how this process differs for the two main types of photoreceptor.

Feedback: Cone cells connect to bipolar cells, which connect with ganglion cells. Rods also connect with bipolar cells, but these bipolar cells do not connect directly to ganglion cells: their signals are instead integrated with cone bipolar cells via amacrine cells.

Subhead: Synaptic Organization of the Retina

Learning Objective: Describe the synaptic organization of the rod and cone pathways in the retina.

Bloom’s Level: 1. Remembering

Type: essay/short answer question

Title: Chapter 22 Question 44

44. Using 1-2 sentences, describe how the three different types of cones contribute to color vision in humans.

Feedback: Different cones respond to different wavelengths of light. Signals from cones then combine to produce a wide variety of colors that are all composed of the three base colors of green, red, and blue.

Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Define the three types of cones that contribute to color vision in humans.

Bloom’s Level: 2. Understanding

Type: essay/short answer question

Title: Chapter 22 Question 45

45. Describe two marked differences between rods and cones.

Feedback: Rods contain pigment inside the cell membrane while cones contain pigment continuous with the cell membrane. Rods also greatly outnumber cones in the retina.

Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Describe the three principal features of photoreceptor structure.

Bloom’s Level: 2. Understanding

Type: essay/short answer question

Title: Chapter 22 Question 46

46. Using your knowledge of the anatomy of the human retina, describe a possible experiment that would reveal where the blind spot created by optic nerves leaving the retina is located in an individual’s visual field (hint: you can only do this with one eye open).

Feedback: Have an individual focus on a stimulus with one eye closed. Because the blind spot is not in the fovea, it will be revealed somewhere in the periphery. Have another stimulus located to the side of the focal stimulus, and then have the individual move closer or further away from the central stimulus until the peripheral stimulus disappears. This is the retinal blind spot.

Subhead: Phototransduction in Retinal Rods and Cones

Learning Objective: Explain why there are two blind spots in the human eye.

Bloom’s Level: 6. Creating

Type: essay/short answer question

Title: Chapter 22 Question 47

47. Your grandfather is telling a story about how when he was camping in the northern part of Canada, he saw a black bear one night that was “as big as a grizzly.” Knowing that black bears are usually a fraction of the size of a grizzly, how might you respond to this story?

Feedback: I might tell my grandfather that at night, we are unable to see color because the photoreceptors responsible for color vision are not sensitive enough to be active. Therefore, a brown grizzly bear will likely look black in dim starlight.

Subhead: Visual Pigments

Learning Objective: Explain why night-vision in humans is color-blind.

Bloom’s Level: 3. Applying

Type: essay/short answer question

Title: Chapter 22 Question 48

48. Describe what happens to the pigment rhodopsin when a photon of light hits it.

Feedback: The shape of rhodopsin changes into metarhodopsin-I and then metarhodopsin-II. It then rebinds with all-trans retinal to return to its original shape.

Subhead: Visual Pigments

Learning Objective: Discuss the role that rhodopsin plays in transduction.

Bloom’s Level: 1. Remembering

Type: essay/short answer question

Title: Chapter 22 Question 49

49. Briefly describe the state of photoreceptors in darkness in terms of their electric potential.

Feedback: In darkness, sodium and calcium channels are open. This allows these ions to flow freely into the cell which keeps it depolarized at rest.

Subhead: Transduction

Learning Objective: Describe, in general terms, how light produces electrical signals in the retina.

Bloom’s Level: 2. Understanding

Type: essay/short answer question

Title: Chapter 22 Question 50

50. Describe a possible reason why it is advantageous for humans to be able to adapt quickly to changes in ambient illumination.

Feedback: If humans could not adapt to constant bright illumination, our rods and cones would quickly become saturated, with all ion channels closed in response to photons. This would greatly impair our visual acuity and possibly cause cell damage.

Subhead: Transduction

Learning Objective: Describe, in general terms, how light produces electrical signals in the retina.

Bloom’s Level: 3. Applying

Type: essay/short answer question

Title: Chapter 22 Question 51

51. Historical legend suggests that pirates used to wear eye patches over one good eye so that they could quickly switch to using the usually-covered eye when entering the darkened holds of enemy ships. Does this legend have merit from a physiological standpoint? Why or why not?

Feedback: This does have merit. It takes many minutes for rods to adapt to darkness, so having one eye that is already dark adapted (the covered eye) would make it easier for pirates to see in the dark quickly by uncovering that eye.

Subhead: Transduction

Learning Objective: Give three ways by which a fall in intracellular calcium affects adaptation of photoreceptors to light.

Bloom’s Level: 4. Analyzing

Type: essay/short answer question

Title: Chapter 22 Question 52

52. Name one thing pigments in rods and cones have in common, and describe the major way in which pigments in rods and cones differ that leads to their differing responses to light.

Feedback: All pigments contain 11-cis retinal. The major way in which pigments differ is in the structure of a few amino acids within the pigment.

Subhead: Transduction

Learning Objective: Explain what accounts for the ability of different visual pigments to trap specific wavelengths of light preferentially.

Bloom’s Level: 1. Remembering

Type: essay/short answer question

Title: Chapter 22 Question 53

53. Describe how lacking just one type of cone can cause color blindness in humans.

Feedback: Full color vision is the result of a combination of three primary colors which are represented by three types of cones. When one cone is missing, the variety of colors is greatly diminished, as you can only combine two colors instead of the usual three.

Subhead: Transduction

Learning Objective: Explain what causes color blindness and give two examples of color blindness in humans.

Bloom’s Level: 2. Understanding

Type: essay/short answer question

Title: Chapter 22 Question 54

54. Receptive fields are an important concept to understand when studying the retina. Define receptive fields and describe their organization.

Feedback: The receptive field is the location on the retina that, when illuminated, impacts the activity of its associated cell. Receptive fields are circular, with opposite impacts if the center of the receptive field is illuminated or the surrounding area.

Subhead: Integration of Visual Inputs

Learning Objective: Discuss two important features of the mammalian visual system that were revealed by Kuffler’s recordings of retinal ganglion cells.

Bloom’s Level: 1. Remembering

Type: essay/short answer question

Title: Chapter 22 Question 55

55. Early one evening, you are struck by how vivid the blue flowers in your garden appear. You quickly pull out your phone and take a flash picture of your garden. However, you are dismayed to see that the blue flowers in your photo are muted compared to the red flowers. Assuming a camera works the same way as a human eye, what might explain this effect?

Feedback: In the dim evening light, the Purkinje effect had the consequence of making blues appear more vivid. When the camera took a photo with the flash, the increased brightness of the light caused the reds to become vivid once more.

Subhead: Synaptic Organization of the Retina

Learning Objective: Define the Purkinje effect.

Bloom’s Level: 3. Applying

Type: essay/short answer question

Title: Chapter 22 Question 56

56. There are three main categories of regional ganglion cells. Name the three types and give an example of the information they carry.

Feedback: Magnocellular (M) cells carry information about contrast and movement. Parvocellular (P) cells carry information about red-green color vision. Koniocellular (K) cells carry information about spatial properties.

Subhead: Receptive Fields and Projections of Ganglion Cells

Learning Objective: Summarize the characteristics of the three principal categories of retinal ganglion cells.

Bloom’s Level: 1. Remembering