Question 1

_______ are found in the _______ layer of the retina.

Accepted Answer

A)  Ganglion cells, deepest 
B)  Bipolar cells, deepest 
C)  Horizontal cells, middle 
D)  Amacrine cells, outermost 
E)  Photoreceptors, deepest 
A)  Ganglion cells, deepest 
B)  Bipolar cells, deepest 
C)  Horizontal cells, middle 
D)  Amacrine cells, outermost 
E)  Photoreceptors, deepest

Question 2

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

Accepted Answer

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. 
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.

Question 3

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

Accepted Answer

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. 
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.

Question 4

_______ cones generally outnumber _______ cones in humans.

Accepted Answer

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) 
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)

Question 5

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

Accepted Answer

A)  calcium and sodium 
B)  potassium and calcium 
C)  sodium and chlorine 
D)  chlorine and calcium 
E)  potassium and sodium 
A)  calcium and sodium 
B)  potassium and calcium 
C)  sodium and chlorine 
D)  chlorine and calcium 
E)  potassium and sodium

Question 6

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?

Accepted Answer

In the dim evening light, the Purkinje e

Question 7

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

Accepted Answer

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. 
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.

Question 8

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

Accepted Answer

A)  potassium 
B)  calcium 
C)  sodium 
D)  chlorine 
E)  carbon 
A)  potassium 
B)  calcium 
C)  sodium 
D)  chlorine 
E)  carbon

Question 9

Amacrine type II (AII) cells primarily synapse with

Accepted Answer

A)  D bipolar cells. 
B)  H bipolar cells. 
C)  ganglion cells. 
D)  D bipolar cells and H bipolar cells. 
E)  horizontal cells. 
A)  D bipolar cells. 
B)  H bipolar cells. 
C)  ganglion cells. 
D)  D bipolar cells and H bipolar cells. 
E)  horizontal cells.

Question 10

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

Accepted Answer

In darkness, sodium and calciu

Question 11

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

Accepted Answer

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. 
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.

Question 12

Retinal plays a key role in preventing rhodopsin from

Accepted Answer

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. 
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.

Question 13

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.

Accepted Answer

All pigments contain 11-cis re

Question 14

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

Accepted Answer

A)  Rods 
B)  Amacrine cells 
C)  Bipolar cells 
D)  Cones 
E)  Horizontal cells 
A)  Rods 
B)  Amacrine cells 
C)  Bipolar cells 
D)  Cones 
E)  Horizontal cells

Question 15

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?

Accepted Answer

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. 
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.

Question 16

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

Accepted Answer

Full color vision is the result of a com

Question 17

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).

Accepted Answer

Have an individual focus on a stimulus w

Question 18

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?

Accepted Answer

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. 
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.

Question 19

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?

Accepted Answer

A)  Seconds 
B)  Picoseconds 
C)  Minutes 
D)  Up to an hour 
E)  Microseconds 
A)  Seconds 
B)  Picoseconds 
C)  Minutes 
D)  Up to an hour 
E)  Microseconds

Question 20

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?

Accepted Answer

I might tell my friend that our visual a

Exam 22: Transduction and Transmission in the Retina

_______ are found in the _______ layer of the retina.

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

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

_______ cones generally outnumber _______ cones in humans.

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

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

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

Amacrine type II (AII) cells primarily synapse with

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

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

Retinal plays a key role in preventing rhodopsin from

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.

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

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?

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

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).

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?

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?

Principles of Signaling and Organization

Signaling in the Visual System

Functional Architecture of the Visual Cortex

Ion Channels and Signaling

Structure of Ion Channels

Ionic Basis of the Resting Potential

Ionic Basis of the Action Potential

Electrical Signaling in Neurons

Ion Transport Across Cell Membranes

Properties and Functions of Neuroglial Cells

Mechanisms of Direct Synaptic Transmission

Indirect Mechanisms of Synaptic Transmission

Release of Neurotransmitters

Neurotransmitters in the Central Nervous System

Transmitter Synthesis, Storage, Transport, and Inactivation

Synaptic Plasticity

The Molecular and Cellular Biology of Synaptic Plasticity

Mechanisms of Extrasynaptic Communication

Autonomic Nervous System

Walking, Flying, and Swimming: Cellular Mechanisms of Sensorimotor Behavior in Invertebrates

Sensory Transduction

Touch, Pain, and Texture Sensation

Auditory and Vestibular Sensation

Constructing Perception

Initiation and Control of Coordinated Muscular Movements

Development of the Nervous System

Critical Periods in Sensory Systems

Regeneration and Repair of Synaptic Connections After Injury

Appendix

Filters

_ are found in the _ layer of the retina.

_ cones generally outnumber _ cones in humans.