Student ID _______________________________
Animal Physiology 2006
Exam II
Name ____________________________________
Part I
Part II
Part III
Part IV
Part V
Part VI
Part VII
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___________ (10)
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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.
copyright www.raytroll.com
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.
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Student ID _______________________________
I) Explain what physiological principle and/or what example each animal was used to
demonstrate Do 4 of 6. 3 pts each
a) Poison arrow/dart frogs
b) Aplysia
c) Jelly fish
d) Squid
e) Malapterus electricus
f) Limulus
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Student ID _______________________________
II) Short answer
1) Name the two investigators that did pioneering work on the horseshoe crab. (2 pts)
2) Name the two investigators who did pioneering work on the visual system using the cat as a
model (2 pts)
3) Which retinal cell does light first encounter when it first hits the retina (1 pt)
4) Name three of the four major tastes discussed in lecture and the evolutionary significance of
each taste (6 pts)
5) The mammalian range of hearing is approximately 40 Hz to 14 Khz. Which of the following
frequencies would be properly encoded closest to the round window of the mammalian cochlea?
(2 pts)
Which of the following frequencies would be properly encoded closest to the oval window (2
pts)
10 Hz, 1000 Hz, 10,000 Hz, 100,000 Hz, 1000 KHz,
2 Khz,
100Hz,
6 Khz
6) If the ear can detect a sound that has a frequency of 60,000 cycles per minute, what would be
the frequency of the sound in Hz? (1 pt)
7) The name of the canals that help control equilibrium and balance (2 pts)
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Student ID _______________________________
III) Longer answer Do 3 of 4. 5 pts each
1) Define ILD and ITD and explain what each is used for by the owl during target acquisition
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) Explain why the action potential propagates in only one direction
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Student ID _______________________________
IV) Figures
Figure 1
What is specific structure in the middle of the top half of figure 1? (2 pts)
What is the functional significance of the structure (2 pts)
What specific type of animal that was discussed in lecture would possess the structure in the top of
the photo. ( 1 pt)
Figure 2
What is figure 2 demonstrating (2 pts). What is the functional significance of this? (3 pts)
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Student ID _______________________________
V. True or False (Do 3 of 4) 5 pts each. 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) In the toad vision experiment, as the square stimulus increased uniformly in size there was a
bimodal behavioral response to the stimulus
4) The following sequence is the correct order for visual transduction
LGN> ganglion cell > photoreceptor > complex cell > simple cell > bipolar cell
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Student ID _______________________________
VI: 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 On- bipolar cell. The On bipolar cell
synapses directly to the On-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; 10pts total if all correct)
I
II
III
Photoreceptor
(in inner circle)
On bi polar cell
On ganglion cell
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VII) Each scenario = 4 pts 20 pts total
Sensory cell A synapses to Neuron C which synapses to Neuron E
Sensory cell B synapses to Neuron D which synapses to Neuron C and Neuron F.
Neuron F synapses to interneuron G which synapses to Neuron H which synapses to muscle I
For every 10 quanta of energy absorbed, the sensory cells will change the membrane voltage of their
postsynaptic target by 5 mV. Anytime the membrane is depolarized by +20 mv, an Action Potential will be
generated by the neuron. Assume each action potential (AP) lasts 2 ms. Neuron C has an absolute
refractory period of 5 ms and Neuron D has an absolute refractory period of 5 ms. During the action
potential and refractory state, any quanta absorbed by the sensory cell is lost (you cannot add quanta during
this period). Assume for this exercise there is no relative refractory period. Neurons C, E, F and H are
silent and will only fire an AP when stimulated. Neuron E needs three APs from Neuron C to fire one AP.
Neuron D has a spontaneous discharge rate of 20 Hz. For every 5 APs from D, neuron F will fire one AP.
Interneuron G is also silent. For every two action potentials it receives from neuron F, it will generate one
AP. Neuron H will fire an AP every time it receives one from interneuron G. One AP=muscle twitch for
muscle I
Scenario I) Sensory cell A receives 20 quanta simultaneously every 10 ms for 500 ms. How many action
potentials will be generated in neuron E.
Scenario II) Sensory cell A receives 2 quanta/ms for 100 ms. How many action potentials will be
generated in neuron E.
Scenario III) Sensory cell B receives with 15 quanta every 10 ms for 500 ms. Yet neuron F fails to fire an
AP. Please explain what is happening compared to scenario I.
Scenario IV) Based on what you deduced from scenario III answer the following. Toxins from the genus
Clostridium prevent the release of neurotransmitter. If this toxin is added to the synapse between B and D,
calculate how many APs will be generated in Neuron F when sensory cell B is hit with 10 quanta every 10
ms for 1000 ms.
Scenario V) Batrachotoxin is added to the prep. How many times will muscle I twitch if sensory cell B
receives 5 quanta/ms for 500 ms.
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Student ID _______________________________
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