Student ID _______________________________
Animal Physiology 2007
Exam II
Name ____________________________________
Part I
Part II
Part III
Part IV
Part V
Part VI
Part VII
Part VIII
Part IX
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Total
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Please read each question carefully. Make sure you completely answer each question. In some sections, you will
be able to choose which questions you would like to answer. Please clearly indicate which of these questions you
have chosen. You are more than welcome to use properly labeled graphs, diagrams, illustrations to support your
conclusions
No electronic devices may be accessed during this exam.
This exam has eight pages including this title page.
Animal Physiology regrade policy: If you feel a mistake has been made in the grading of your exam, please
submit a typed explanation to Dr. Mensinger within one week of your exam being returned. You should detail
why you feel your answer deserves more credit.
I) Which of the following senses (taste, olfaction, vision, mechanoreception, auditory, weakly electric,
strongly electric, infrared, bioluminescence, anti gravity) were the following used to illustrate or mostly
closely aligned with. Do 10 of 13. 1 pt each.
a) Bombyx
b) The fly
c) schooling fish
d) barn owl
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e) Malapterus electricus
f) Limulus
g) worm/antiworm
h) the cat
i) cheetah
j) bird of prey (raptor)
k) mormyrid
l) torpedo
m) pit viper
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II) Short answer
1) Name the two investigators that did pioneering work on the horseshoe crab. (2 pts)
2) Which retinal cell does light first encounter when it first hits the retina (2 pt)
3) Name two of the five major tastes discussed in lecture and the evolutionary significance of each taste
(5 pts)
4) What was the sea slug, Aplysia, used as a model organism for? (2 pts)
5) What compound does the puffer fish contain and how did it help scientist understand the ionic basis
of the action potential. What channel did it block (2 pts)
6) What type of photoreceptor would dominate your vision if you looked out the corner of your eye. ( 2
pt)
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Student ID _______________________________
III: Sketch the membrane potential for each cell in the table boxes to show its reaction to a brief light
stimulus. The location(s) of the stimulus is indicated by X. The photoreceptor is contained within the
smaller, inside circle and synapses directly to the off- bipolar cell. The off bipolar cell synapses directly
to the off center ganglion cell. For these questions you do not have to worry about labeling the axes or
drawing a scale bar. You just need to show how the membrane potential will change during a brief light
stimulus (1 pts each square; 10 pts total if all correct)
I
II
III
Photoreceptor
(in inner circle)
Off bi polar cell
Off ganglion cell
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IV) Longer answer Do 3 of 4. 5 pts each
1) Explain the figure. Make sure you Describe the purpose of the plug, the purpose of two different
types of plugs and how the plugs affected the owl’s ability to locate the target. What was learned about
sound localization from the experiment.
2) Explain how a small dart tipped with curare can bring down a monkey.
3) Explain why electrical communication is better than acoustical communication in shallow water
habit.
4) If one takes a long axon and applies current to the middle of this axon, current will spread in both
directions. Yet, if a spike is initiated in the axon hill lock, the action potential will only travel in one
direction. Explain. A figure is suggested.
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V) Do one of the following 2 questions (nerve gas or shark, shark is on next page). 10 pts
1) While trawling in Lake Superior, you bring aboard a shell labeled DANGER: NERVE GAS. Explain the
physiological consequences that your nervous system will undergo if this shell ruptures. Please be specific about
what is happening at the synaptic junction and what will be the ultimate cause of death. (7 pts)
Pyridostigmine bromide is a nerve gas antidote. Taking into account what you know about nerve gas, postulate a
mechanism that would allow Pyridostigmine bromide to work (3 pts)
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Student ID _______________________________
2) Label 5 structures on the dogfish brain
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VI) Plot the membrane potential (mV) vs time for the following cell. Start at T=0 ms for each scenario. All times are in
relation to T=0. The cell has a resting potential of -50mv, a threshold of -30, an ENA of approximately +50. The absolute
refractory period of the cell is 3 ms and the relative refractory period lasts an additional 2 ms after the absolute refractory
period. Each stimulus is 2 ms in duration. The time constant for the action potential is the same as mentioned in lecture and
shown in your textbook. (2.5 pts each)
Membrane potential (mV)
A) A hyper polarizing stimulus of 25 mv at + 1 ms
100
80
60
40
20
0
-20
-40
-60
-80
-100
0
2
4
6
8
10
TIME (ms)
Membrane potential (mV)
B) A depolarizing stimulus of 10 mv at + 1 ms
100
80
60
40
20
0
-20
-40
-60
-80
-100
0
2
4
6
8
10
TIME (ms)
Membrane potential (mV)
C) a depolarizing stimulus of 40 mv at +1 ms and a depolarizing stimulus of 40 mv at +4 ms
100
80
60
40
20
0
-20
-40
-60
-80
-100
0
2
4
6
8
10
TIME (ms)
Membrane potential (mV)
D) A depolarizing Stimulus of 35 mv at +1ms and a depolarizing stimulus of 50 mv at +8 ms
100
80
60
40
20
0
-20
-40
-60
-80
-100
0
2
4
6
8
10
TIME (ms)
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VII) Do one of the following 10 pts
A) Draw an action potential. Using dotted or dashed lines, Plot gNa+ and gK+ in relation to the action
potential. Compound X blocks K+ channels. Redraw the action potential to show the effect of
Compound X
B) Compound Y destroys the inactivating particle in voltage gated Na+ channels. Everything else
remains intact in the channel. Speculate on what effect this would have following a depolarization past
threshold in the neuron following treatment with compound Y. Do not forget to include ENA+ in your
discussion.
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Student ID _______________________________
VIII. True or False (Do 3 of 5) 3 pts each (=+1pt for all correct trues/false). Indicate whether the following
statements are true or false. If the statement is true, provide a figure/graph that supports the claim. If the
statement is false, correct the entire statement.
1) Stimulus modality is encoded by both the amplitude and the duration of the action potential
2) Frequency varies linearly with the size of the receptor potential but cannot exceed the limit set by the
refractory period.
3) For an on-center ganglion cell, the firing rate of the cell will increase in response to a small spot of light
centered on the cell and decrease in response to a “ring” of light that only covers its surround
4) Simple cells are characteristics of the lateral geniculate nucleus. They are influenced primarily by the on and
off center of retinal bipolar cells. They will respond to the proper stimuli anywhere within a large visual field
5) Vertebrate photoreceptors do not release neurotransmitter in the dark because of the dark current. When
stimulated by photons, their membrane will depolarize. The stimulus from the photoreceptor is in the form of an
action potential. This stimulus travels from photoreceptors to horizontal cells to ganglion cells. At the ganglion
cell level, the action potential is converted to a graded potential that is sent directly to the visual cortex.
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IX) 10 pts
Neuron A synapses onto Neuron B.
Electrode I is placed at a node of Ranvier along the axon of Neuron A.
Electrode II is placed at a myelinated section along the axon of Neuron A
Electrode III is placed in the dendrites of Neuron B.
For each of the following cases, sketch the voltage recorded by the electrode (for example, if an action potential
will be taking place at that location, draw an action potential). Relative scale is more important than absolute
scale so you do not have to label the x and y axis. Assume a single action potential in neuron A is sufficient to
generate a post synaptic event in neuron B.
TEA blocks most types of K+ channels
Bungarotoxin inhibits neurotransmitter release from the presynaptic terminals
The following cases all follow the generation of an action potential at the axon hill lock in neuron following
application of the following:
Case #1
Case #2
Case #3
no drugs
TEA
Bungarotoxin
I
II
III
#1
#2
#3
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